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Mechanisms of Drought, Temperature and Salinity Tolerance in Plants
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Mechanisms of Drought, Temperature and Salinity Tolerance in Plants

A special issue of International Journal of Molecular Sciences (ISSN 1422-0067). This special issue belongs to the section "Molecular Plant Sciences".

Deadline for manuscript submissions: closed (28 February 2022) | Viewed by 131923

Special Issue Editors

Prof. Dr. Om Parkash Dhankher

E-Mail Website
Guest Editor
Stockbridge School of Agriculture, University of Massachusetts Amherst, Amherst, MA, USA
Interests: climate-resilient crops; glutathione homoestasis; metabolic engineering; salinity stress; drought stress; heavy metals stress; tolerance
Special Issues, Collections and Topics in MDPI journals
Prof. Dr. P.V. Vara Prasad

E-Mail Website
Guest Editor
Sustainable Intensification Innovation Lab, Kansas State University, Manhattan, KS 66506, USA
Interests: sustainable intensification innovation; food security; crop stress physiology; climate change
Special Issues, Collections and Topics in MDPI journals
Prof. Dr. Sergey Shabala

grade E-Mail Website
Guest Editor
Tasmanian Institute of Agriculture, College of Science and Engineering, University of Tasmania, Hobart 7001, Australia
Interests: stress physiology; membrane transport; extreme temperature; salinity stress; drought stress; oxidative stress
Special Issues, Collections and Topics in MDPI journals

Special Issue Information

Dear Colleagues,

Environmental stresses, particularly drought, temperature (high/heat and cold temperatures) and salinity, are among the main causes of declining crop productivity and is threatening the global food and nutritional security. World population is projected to grow to 9.7 billion by 2050 and over 10 billion people by the end of 2100. The intensity of extreme abiotic stress events including frequent drought, extreme temperatures (cold and heat), salinity, flooding, and heavy metals contamination as a result of climate change is expected to be more frequent. These events will threaten the crop productivity and will create a loss of billions of dollars of farmer income. In the current and future climate change scenarios, there is a critical need for developing crops that can grow and produce better yields and have nutritious quality under these environmental stress conditions. Further, understanding the biochemical, physiological, and genetic mechanisms is critical to improve plant tolerance to these stresses. In recent years, due to the advancement in the ‘omics’ and breeding technologies, a significant progress has been made in this direction but the knowledge gaps still exist. Additionally, the efforts in translating the knowledge gained through basic research should be expedited to achieve the desired outcomes of enhancing crop productivity and ensuing the global food and nutritional security. The papers published in this Special Issue will focus on the mechanisms of drought, temperature, and salinity tolerance in plants for enabling the crops to perform under the above-mentioned stress conditions with minimum impacts of crop yields and quality. All plant and crop species with economic importance and value will be considered.

The manuscripts submitted to this Special Issue must report high novelty and hypothesis driven results. The papers published in this Special Issue will focus on the mechanisms of drought, temperature and salinity tolerance in plants, seeking to enable crops to grow and perform under these stress conditions with minimum impacts of crop yields and quality. Papers dealing with the translational and transdisciplinary approaches to address yield (economic) formation and nutritional quality of all plant species are also welcome.

Prof. Dr. Om Parkash Dhankher
Prof. Dr. P.V. Vara Prasad
Prof. Dr. Sergey Shabala
Guest Editors

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All submissions that pass pre-check are peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. International Journal of Molecular Sciences is an international peer-reviewed open access semimonthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. There is an Article Processing Charge (APC) for publication in this open access journal. For details about the APC please see here. Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

  • Drought stress
  • Temperature stress
  • Salinity stress
  • Molecular
  • Biochemical
  • Physiological
  • Adaptive mechanisms
  • Climate resilient crops
  • Food security
  • Translational research

Published Papers (35 papers)

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30 pages, 16903 KiB  
Article
Genetic Conservation of CBS Domain Containing Protein Family in Oryza Species and Their Association with Abiotic Stress Responses
by Surabhi Tomar, Ashish Subba, Meenu Bala, Anil Kumar Singh, Ashwani Pareek and Sneh Lata Singla-Pareek
Int. J. Mol. Sci. 2022, 23(3), 1687; https://0-doi-org.brum.beds.ac.uk/10.3390/ijms23031687 - 01 Feb 2022
Cited by 12 | Viewed by 2805
Abstract
Crop Wild Relatives (CWRs) form a comprehensive gene pool that can answer the queries related to plant domestication, speciation, and ecological adaptation. The genus ‘Oryza’ comprises about 27 species, of which two are cultivated, while the remaining are wild. Here, we have [...] Read more.
Crop Wild Relatives (CWRs) form a comprehensive gene pool that can answer the queries related to plant domestication, speciation, and ecological adaptation. The genus ‘Oryza’ comprises about 27 species, of which two are cultivated, while the remaining are wild. Here, we have attempted to understand the conservation and diversification of the genes encoding Cystathionine β-synthase (CBS) domain-containing proteins (CDCPs) in domesticated and CWRs of rice. Few members of CDCPs were previously identified to be stress-responsive and associated with multiple stress tolerance in rice. Through genome-wide analysis of eleven rice genomes, we identified a total of 36 genes encoding CDCPs in O. longistaminata, 38 in O. glaberrima, 39 each in O. rufipogon, O. glumaepatula, O. brachyantha, O. punctata, and O. sativa subsp. japonica, 40 each in O. barthii and O. meridionalis, 41 in O. nivara, and 42 in O. sativa subsp. indica. Gene duplication analysis as well as non-synonymous and synonymous substitutions in the duplicated gene pairs indicated that this family is shaped majorly by the negative or purifying selection pressure through the long-term evolution process. We identified the presence of two additional hetero-domains, namely TerCH and CoatomerE (specifically in O. sativa subsp. indica), which were not reported previously in plant CDCPs. The in silico expression analysis revealed some of the members to be responsive to various abiotic stresses. Furthermore, the qRT-PCR based analysis identified some members to be highly inducive specifically in salt-tolerant genotype in response to salinity. The cis-regulatory element analysis predicted the presence of numerous stress as well as a few phytohormone-responsive elements in their promoter region. The data presented in this study would be helpful in the characterization of these CDCPs from rice, particularly in relation to abiotic stress tolerance. Full article
(This article belongs to the Special Issue Mechanisms of Drought, Temperature and Salinity Tolerance in Plants)
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17 pages, 1922 KiB  
Article
ASRmiRNA: Abiotic Stress-Responsive miRNA Prediction in Plants by Using Machine Learning Algorithms with Pseudo K-Tuple Nucleotide Compositional Features
by Prabina Kumar Meher, Shbana Begam, Tanmaya Kumar Sahu, Ajit Gupta, Anuj Kumar, Upendra Kumar, Atmakuri Ramakrishna Rao, Krishna Pal Singh and Om Parkash Dhankher
Int. J. Mol. Sci. 2022, 23(3), 1612; https://0-doi-org.brum.beds.ac.uk/10.3390/ijms23031612 - 30 Jan 2022
Cited by 9 | Viewed by 3354
Abstract
MicroRNAs (miRNAs) play a significant role in plant response to different abiotic stresses. Thus, identification of abiotic stress-responsive miRNAs holds immense importance in crop breeding programmes to develop cultivars resistant to abiotic stresses. In this study, we developed a machine learning-based computational method [...] Read more.
MicroRNAs (miRNAs) play a significant role in plant response to different abiotic stresses. Thus, identification of abiotic stress-responsive miRNAs holds immense importance in crop breeding programmes to develop cultivars resistant to abiotic stresses. In this study, we developed a machine learning-based computational method for prediction of miRNAs associated with abiotic stresses. Three types of datasets were used for prediction, i.e., miRNA, Pre-miRNA, and Pre-miRNA + miRNA. The pseudo K-tuple nucleotide compositional features were generated for each sequence to transform the sequence data into numeric feature vectors. Support vector machine (SVM) was employed for prediction. The area under receiver operating characteristics curve (auROC) of 70.21, 69.71, 77.94 and area under precision-recall curve (auPRC) of 69.96, 65.64, 77.32 percentages were obtained for miRNA, Pre-miRNA, and Pre-miRNA + miRNA datasets, respectively. Overall prediction accuracies for the independent test set were 62.33, 64.85, 69.21 percentages, respectively, for the three datasets. The SVM also achieved higher accuracy than other learning methods such as random forest, extreme gradient boosting, and adaptive boosting. To implement our method with ease, an online prediction server “ASRmiRNA” has been developed. The proposed approach is believed to supplement the existing effort for identification of abiotic stress-responsive miRNAs and Pre-miRNAs. Full article
(This article belongs to the Special Issue Mechanisms of Drought, Temperature and Salinity Tolerance in Plants)
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15 pages, 6787 KiB  
Article
SiMYB19 from Foxtail Millet (Setaria italica) Confers Transgenic Rice Tolerance to High Salt Stress in the Field
by Chengjie Xu, Mingzhao Luo, Xianjun Sun, Jiji Yan, Huawei Shi, Huishu Yan, Rongyue Yan, Shuguang Wang, Wensi Tang, Yongbin Zhou, Chunxiao Wang, Zhaoshi Xu, Jun Chen, Youzhi Ma, Qiyan Jiang, Ming Chen and Daizhen Sun
Int. J. Mol. Sci. 2022, 23(2), 756; https://0-doi-org.brum.beds.ac.uk/10.3390/ijms23020756 - 11 Jan 2022
Cited by 15 | Viewed by 2728
Abstract
Salt stress is a major threat to crop quality and yield. Most experiments on salt stress-related genes have been conducted at the laboratory or greenhouse scale. Consequently, there is a lack of research demonstrating the merit of exploring these genes in field crops. [...] Read more.
Salt stress is a major threat to crop quality and yield. Most experiments on salt stress-related genes have been conducted at the laboratory or greenhouse scale. Consequently, there is a lack of research demonstrating the merit of exploring these genes in field crops. Here, we found that the R2R3-MYB transcription factor SiMYB19 from foxtail millet is expressed mainly in the roots and is induced by various abiotic stressors such as salt, drought, low nitrogen, and abscisic acid. SiMYB19 is tentatively localized to the nucleus and activates transcription. It enhances salt tolerance in transgenic rice at the germination and seedling stages. SiMYB19 overexpression increased shoot height, grain yield, and salt tolerance in field- and salt pond-grown transgenic rice. SiMYB19 overexpression promotes abscisic acid (ABA) accumulation in transgenic rice and upregulates the ABA synthesis gene OsNCED3 and the ABA signal transduction pathway-related genes OsPK1 and OsABF2. Thus, SiMYB19 improves salt tolerance in transgenic rice by regulating ABA synthesis and signal transduction. Using rice heterologous expression analysis, the present study introduced a novel candidate gene for improving salt tolerance and increasing yield in crops grown in saline-alkali soil. Full article
(This article belongs to the Special Issue Mechanisms of Drought, Temperature and Salinity Tolerance in Plants)
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31 pages, 4819 KiB  
Article
Ascorbate–Glutathione Oxidant Scavengers, Metabolome Analysis and Adaptation Mechanisms of Ion Exclusion in Sorghum under Salt Stress
by Himani Punia, Jayanti Tokas, Anurag Malik, Andrzej Bajguz, Mohamed A. El-Sheikh and Parvaiz Ahmad
Int. J. Mol. Sci. 2021, 22(24), 13249; https://0-doi-org.brum.beds.ac.uk/10.3390/ijms222413249 - 09 Dec 2021
Cited by 19 | Viewed by 2152
Abstract
Salt stress is one of the major significant restrictions that hamper plant development and agriculture ecosystems worldwide. Novel climate-adapted cultivars and stress tolerance-enhancing molecules are increasingly appreciated to mitigate the detrimental impacts of adverse stressful conditions. Sorghum is a valuable source of food [...] Read more.
Salt stress is one of the major significant restrictions that hamper plant development and agriculture ecosystems worldwide. Novel climate-adapted cultivars and stress tolerance-enhancing molecules are increasingly appreciated to mitigate the detrimental impacts of adverse stressful conditions. Sorghum is a valuable source of food and a potential model for exploring and understanding salt stress dynamics in cereals and for gaining a better understanding of their physiological pathways. Herein, we evaluate the antioxidant scavengers, photosynthetic regulation, and molecular mechanism of ion exclusion transporters in sorghum genotypes under saline conditions. A pot experiment was conducted in two sorghum genotypes viz. SSG 59-3 and PC-5 in a climate-controlled greenhouse under different salt concentrations (60, 80, 100, and 120 mM NaCl). Salinity drastically affected the photosynthetic machinery by reducing the accumulation of chlorophyll pigments and carotenoids. SSG 59-3 alleviated the adverse effects of salinity by suppressing oxidative stress (H2O2) and stimulating enzymatic and non-enzymatic antioxidant activities (SOD, APX, CAT, POD, GR, GST, DHAR, MDHAR, GSH, ASC, proline, GB), as well as protecting cell membrane integrity (MDA, electrolyte leakage). Salinity also influenced Na+ ion efflux and maintained a lower cytosolic Na+/K+ ratio via the concomitant upregulation of SbSOS1, SbSOS2, and SbNHX-2 and SbV-Ppase-II ion transporter genes in sorghum genotypes. Overall, these results suggest that Na+ ions were retained and detoxified, and less stress impact was observed in mature and younger leaves. Based on the above, we deciphered that SSG 59-3 performed better by retaining higher plant water status, photosynthetic assimilates and antioxidant potential, and the upregulation of ion transporter genes and may be utilized in the development of resistant sorghum lines in saline regions. Full article
(This article belongs to the Special Issue Mechanisms of Drought, Temperature and Salinity Tolerance in Plants)
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20 pages, 8741 KiB  
Article
HbSnRK2.6 Functions in ABA-Regulated Cold Stress Response by Promoting HbICE2 Transcriptional Activity in Hevea brasiliensis
by Xue Wang, Wen-Cheng Liu, Xue-Wei Zeng, Sa Yan, Yi-Min Qiu, Jin-Bo Wang, Xi Huang and Hong-Mei Yuan
Int. J. Mol. Sci. 2021, 22(23), 12707; https://0-doi-org.brum.beds.ac.uk/10.3390/ijms222312707 - 24 Nov 2021
Cited by 4 | Viewed by 1763
Abstract
Low temperature remarkably limits rubber tree (Hevea brasiliensis Muell. Arg.) growth, latex production, and geographical distribution, but the underlying mechanisms of Hevea brasiliensis cold stress response remain elusive. Here, we identified HbSnRK2.6 as a key component in ABA signaling functions in phytohormone [...] Read more.
Low temperature remarkably limits rubber tree (Hevea brasiliensis Muell. Arg.) growth, latex production, and geographical distribution, but the underlying mechanisms of Hevea brasiliensis cold stress response remain elusive. Here, we identified HbSnRK2.6 as a key component in ABA signaling functions in phytohormone abscisic acid (ABA)-regulated cold stress response in Hevea brasiliensis. Exogenous application of ABA enhances Hevea brasiliensis cold tolerance. Cold-regulated (COR) genes in the CBF pathway are upregulated by ABA. Transcript levels of all five HbSnRK2.6 members are significantly induced by cold, while HbSnRK2.6A, HbSnRK2.6B, and HbSnRK2.6C can be further activated by ABA under cold conditions. Additionally, HbSnRK2.6s are localized in the cytoplasm and nucleus, and can physically interact with HbICE2, a crucial positive regulator in the cold signaling pathway. Overexpression of HbSnRK2.6A or HbSnRK2.6B in Arabidopsis extensively enhances plant responses to ABA and expression of COR genes, leading to increased cold stress tolerance. Furthermore, HbSnRK2.6A and HbSnRK2.6B can promote transcriptional activity of HbICE2, thus, increasing the expression of HbCBF1. Taken together, we demonstrate that HbSnRK2.6s are involved in ABA-regulated cold stress response in Hevea brasiliensis by regulating transcriptional activity of HbICE2. Full article
(This article belongs to the Special Issue Mechanisms of Drought, Temperature and Salinity Tolerance in Plants)
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23 pages, 4948 KiB  
Article
Wood Formation under Severe Drought Invokes Adjustment of the Hormonal and Transcriptional Landscape in Poplar
by Dade Yu, Dennis Janz, Krzysztof Zienkiewicz, Cornelia Herrfurth, Ivo Feussner, Shaoliang Chen and Andrea Polle
Int. J. Mol. Sci. 2021, 22(18), 9899; https://0-doi-org.brum.beds.ac.uk/10.3390/ijms22189899 - 13 Sep 2021
Cited by 17 | Viewed by 2856
Abstract
Drought is a severe environmental stress that exerts negative effects on plant growth. In trees, drought leads to reduced secondary growth and altered wood anatomy. The mechanisms underlying wood stress adaptation are not well understood. Here, we investigated the physiological, anatomical, hormonal, and [...] Read more.
Drought is a severe environmental stress that exerts negative effects on plant growth. In trees, drought leads to reduced secondary growth and altered wood anatomy. The mechanisms underlying wood stress adaptation are not well understood. Here, we investigated the physiological, anatomical, hormonal, and transcriptional responses of poplar to strong drought. Drought-stressed xylem was characterized by higher vessel frequencies, smaller vessel lumina, and thicker secondary fiber cell walls. These changes were accompanied by strong increases in abscisic acid (ABA) and antagonistic changes in salicylic acid in wood. Transcriptional evidence supported ABA biosynthesis and signaling in wood. Since ABA signaling activates the fiber-thickening factor NST1, we expected upregulation of the secondary cell wall (SCW) cascade under stress. By contrast, transcription factors and biosynthesis genes for SCW formation were down-regulated, whereas a small set of cellulose synthase-like genes and a huge array of genes involved in cell wall modification were up-regulated in drought-stressed wood. Therefore, we suggest that ABA signaling monitors normal SCW biosynthesis and that drought causes a switch from normal to “stress wood” formation recruiting a dedicated set of genes for cell wall biosynthesis and remodeling. This proposition implies that drought-induced changes in cell wall properties underlie regulatory mechanisms distinct from those of normal wood. Full article
(This article belongs to the Special Issue Mechanisms of Drought, Temperature and Salinity Tolerance in Plants)
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19 pages, 3117 KiB  
Article
Populus euphratica Apyrases Increase Drought Tolerance by Modulating Stomatal Aperture in Arabidopsis
by Yanli Zhang, Yuanling Sun, Xiaojing Liu, Jiayin Deng, Jun Yao, Yinan Zhang, Shurong Deng, Huilong Zhang, Nan Zhao, Jinke Li, Xiaoyang Zhou, Rui Zhao and Shaoliang Chen
Int. J. Mol. Sci. 2021, 22(18), 9892; https://0-doi-org.brum.beds.ac.uk/10.3390/ijms22189892 - 13 Sep 2021
Cited by 6 | Viewed by 1936
Abstract
Stomatal regulation is crucial to reduce water consumption under drought conditions. Extracellular ATP (eATP) serves as a signaling agent in stomatal regulation; however, it is less known whether the eATP mediation of stomatal aperture is linked to apyrases (APYs), the principal enzymes that [...] Read more.
Stomatal regulation is crucial to reduce water consumption under drought conditions. Extracellular ATP (eATP) serves as a signaling agent in stomatal regulation; however, it is less known whether the eATP mediation of stomatal aperture is linked to apyrases (APYs), the principal enzymes that control the concentration of eATP. To clarify the role of APYs in stomatal control, PeAPY1 and PeAPY2 were isolated from Populus euphratica and transferred into Arabidopsis. Compared with the wild-type Arabidopsis and loss-of-function mutants (Atapy1 and Atapy2), PeAPY1- and PeAPY2-transgenic plants decreased stomatal aperture under mannitol treatment (200 mM, 2 h) and reduced water loss during air exposure (90 min). The role of apyrase in stomatal regulation resulted from its control in eATP-regulated stomatal movements and increased stomatal sensitivity to ABA. The bi-phasic dose-responses to applied nucleotides, i.e., the low ATP (0.3–1.0 mM)-promoted opening and high ATP (>2.0 mM)-promoted closure, were both restricted by P. euphratica apyrases. It is noteworthy that eATP at a low concentration (0.3 mM) counteracted ABA action in the regulation of stomatal aperture, while overexpression of PeAPY1 or PeAPY2 effectively diminished eATP promotion in opening, and consequently enhanced ABA action in closure. We postulate a speculative model of apyrase signaling in eATP- and ABA-regulated stomatal movements under drought. Full article
(This article belongs to the Special Issue Mechanisms of Drought, Temperature and Salinity Tolerance in Plants)
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16 pages, 3121 KiB  
Article
Decapitation Experiments Combined with the Transcriptome Analysis Reveal the Mechanism of High Temperature on Chrysanthemum Axillary Bud Formation
by Yujie Yang, Sagheer Ahmad, Qingqing Yang, Cunquan Yuan and Qixiang Zhang
Int. J. Mol. Sci. 2021, 22(18), 9704; https://0-doi-org.brum.beds.ac.uk/10.3390/ijms22189704 - 08 Sep 2021
Cited by 2 | Viewed by 2279
Abstract
Temperature is an important factor that largely affects the patterns of shoot branching in plants. However, the effect and mechanism of temperature on axillary bud development in chrysanthemum remains poorly defined. The purpose of the present study is to investigate the effect of [...] Read more.
Temperature is an important factor that largely affects the patterns of shoot branching in plants. However, the effect and mechanism of temperature on axillary bud development in chrysanthemum remains poorly defined. The purpose of the present study is to investigate the effect of high temperature on the axillary bud growth and the mechanism of axillary bud formation in chrysanthemum. Decapitation experiments combined with the transcriptome analysis were designed. Results showed that the axillary bud length was significantly inhibited by high temperature. Decapitation of primary shoot (primary decapitation) resulted in slower growth of axillary buds (secondary buds) under 35 °C. However, secondary decapitation resulted in complete arrest of tertiary buds at high temperature. These results demonstrated that high temperature not only inhibited axillary bud formation but also retarded bud outgrowth in chrysanthemum. Comparative transcriptome suggested differentially expressed gene sets and identified important modules associated with bud formation. This research helped to elucidate the regulatory mechanism of high temperature on axillary bud growth, especially bud formation in chrysanthemum. Meanwhile, in-depth studies of this imperative temperature signaling can offer the likelihood of vital future applications in chrysanthemum breeding and branching control. Full article
(This article belongs to the Special Issue Mechanisms of Drought, Temperature and Salinity Tolerance in Plants)
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22 pages, 5682 KiB  
Article
Molecular Dissection of the Gene OsGA2ox8 Conferring Osmotic Stress Tolerance in Rice
by Yinxiao Wang, Fengping Du, Juan Wang, Yingbo Li, Yue Zhang, Xiuqin Zhao, Tianqing Zheng, Zhikang Li, Jianlong Xu, Wensheng Wang and Binying Fu
Int. J. Mol. Sci. 2021, 22(17), 9107; https://0-doi-org.brum.beds.ac.uk/10.3390/ijms22179107 - 24 Aug 2021
Cited by 11 | Viewed by 2341
Abstract
Gibberellin 2-oxidase (GA2ox) plays an important role in the GA catabolic pathway and the molecular function of the OsGA2ox genes in plant abiotic stress tolerance remains largely unknown. In this study, we functionally characterized the rice gibberellin 2-oxidase 8 (OsGA2ox8) gene. [...] Read more.
Gibberellin 2-oxidase (GA2ox) plays an important role in the GA catabolic pathway and the molecular function of the OsGA2ox genes in plant abiotic stress tolerance remains largely unknown. In this study, we functionally characterized the rice gibberellin 2-oxidase 8 (OsGA2ox8) gene. The OsGA2ox8 protein was localized in the nucleus, cell membrane, and cytoplasm, and was induced in response to various abiotic stresses and phytohormones. The overexpression of OsGA2ox8 significantly enhanced the osmotic stress tolerance of transgenic rice plants by increasing the number of osmotic regulators and antioxidants. OsGA2ox8 was differentially expressed in the shoots and roots to cope with osmotic stress. The plants overexpressing OsGA2ox8 showed reduced lengths of shoots and roots at the seedling stage, but no difference in plant height at the heading stage was observed, which may be due to the interaction of OsGA2ox8 and OsGA20ox1, implying a complex feedback regulation between GA biosynthesis and metabolism in rice. Importantly, OsGA2ox8 was able to indirectly regulate several genes associated with the anthocyanin and flavonoid biosynthetic pathway and the jasmonic acid (JA) and abscisic acid (ABA) biosynthetic pathway, and overexpression of OsGA2ox8 activated JA signal transduction by inhibiting the expression of jasmonate ZIM domain-containing proteins. These results provide a basis for a future understanding of the networks and respective phenotypic effects associated with OsGA2ox8. Full article
(This article belongs to the Special Issue Mechanisms of Drought, Temperature and Salinity Tolerance in Plants)
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24 pages, 18188 KiB  
Article
Genetic Dissection of Seedling Root System Architectural Traits in a Diverse Panel of Hexaploid Wheat through Multi-Locus Genome-Wide Association Mapping for Improving Drought Tolerance
by Thippeswamy Danakumara, Jyoti Kumari, Amit Kumar Singh, Subodh Kumar Sinha, Anjan Kumar Pradhan, Shivani Sharma, Shailendra Kumar Jha, Ruchi Bansal, Sundeep Kumar, Girish Kumar Jha, Mahesh C. Yadav and P.V. Vara Prasad
Int. J. Mol. Sci. 2021, 22(13), 7188; https://0-doi-org.brum.beds.ac.uk/10.3390/ijms22137188 - 02 Jul 2021
Cited by 21 | Viewed by 3831
Abstract
Cultivars with efficient root systems play a major role in enhancing resource use efficiency, particularly water absorption, and thus in drought tolerance. In this study, a diverse wheat association panel of 136 wheat accessions including mini core subset was genotyped using Axiom 35k [...] Read more.
Cultivars with efficient root systems play a major role in enhancing resource use efficiency, particularly water absorption, and thus in drought tolerance. In this study, a diverse wheat association panel of 136 wheat accessions including mini core subset was genotyped using Axiom 35k Breeders’ Array to identify genomic regions associated with seedling stage root architecture and shoot traits using multi-locus genome-wide association studies (ML-GWAS). The association panel revealed a wide variation of 1.5- to 50-fold and were grouped into six clusters based on 15 traits. Six different ML-GWAS models revealed 456 significant quantitative trait nucleotides (QTNs) for various traits with phenotypic variance in the range of 0.12–38.60%. Of these, 87 QTNs were repeatedly detected by two or more models and were considered reliable genomic regions for the respective traits. Among these QTNs, eleven were associated with average diameter and nine each for second order lateral root number (SOLRN), root volume (RV) and root length density (RLD). A total of eleven genomic regions were pleiotropic and each controlled two or three traits. Some important candidate genes such as Formin homology 1, Ubiquitin-like domain superfamily and ATP-dependent 6-phosphofructokinase were identified from the associated genomic regions. The genomic regions/genes identified in this study could potentially be targeted for improving root traits and drought tolerance in wheat. Full article
(This article belongs to the Special Issue Mechanisms of Drought, Temperature and Salinity Tolerance in Plants)
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23 pages, 3753 KiB  
Article
EMS Derived Wheat Mutant BIG8-1 (Triticum aestivum L.)—A New Drought Tolerant Mutant Wheat Line
by Marlon-Schylor L. le Roux, Nicolas Francois V. Burger, Maré Vlok, Karl J. Kunert, Christopher A. Cullis and Anna-Maria Botha
Int. J. Mol. Sci. 2021, 22(10), 5314; https://0-doi-org.brum.beds.ac.uk/10.3390/ijms22105314 - 18 May 2021
Cited by 8 | Viewed by 2923
Abstract
Drought response in wheat is considered a highly complex process, since it is a multigenic trait; nevertheless, breeding programs are continuously searching for new wheat varieties with characteristics for drought tolerance. In a previous study, we demonstrated the effectiveness of a mutant known [...] Read more.
Drought response in wheat is considered a highly complex process, since it is a multigenic trait; nevertheless, breeding programs are continuously searching for new wheat varieties with characteristics for drought tolerance. In a previous study, we demonstrated the effectiveness of a mutant known as RYNO3936 that could survive 14 days without water. In this study, we reveal another mutant known as BIG8-1 that can endure severe water deficit stress (21 days without water) with superior drought response characteristics. Phenotypically, the mutant plants had broader leaves, including a densely packed fibrous root architecture that was not visible in the WT parent plants. During mild (day 7) drought stress, the mutant could maintain its relative water content, chlorophyll content, maximum quantum yield of PSII (Fv/Fm) and stomatal conductance, with no phenotypic symptoms such as wilting or senescence despite a decrease in soil moisture content. It was only during moderate (day 14) and severe (day 21) water deficit stress that a decline in those variables was evident. Furthermore, the mutant plants also displayed a unique preservation of metabolic activity, which was confirmed by assessing the accumulation of free amino acids and increase of antioxidative enzymes (peroxidases and glutathione S-transferase). Proteome reshuffling was also observed, allowing slow degradation of essential proteins such as RuBisCO during water deficit stress. The LC-MS/MS data revealed a high abundance of proteins involved in energy and photosynthesis under well-watered conditions, particularly Serpin-Z2A and Z2B, SGT1 and Calnexin-like protein. However, after 21 days of water stress, the mutants expressed ABC transporter permeases and xylanase inhibitor protein, which are involved in the transport of amino acids and protecting cells, respectively. This study characterizes a new mutant BIG8-1 with drought-tolerant characteristics suited for breeding programs. Full article
(This article belongs to the Special Issue Mechanisms of Drought, Temperature and Salinity Tolerance in Plants)
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19 pages, 3757 KiB  
Article
Increased Cuticle Waxes by Overexpression of WSD1 Improves Osmotic Stress Tolerance in Arabidopsis thaliana and Camelina sativa
by Hesham M. Abdullah, Jessica Rodriguez, Jeffrey M. Salacup, Isla S. Castañeda, Danny J. Schnell, Ashwani Pareek and Om Parkash Dhankher
Int. J. Mol. Sci. 2021, 22(10), 5173; https://0-doi-org.brum.beds.ac.uk/10.3390/ijms22105173 - 13 May 2021
Cited by 21 | Viewed by 4383
Abstract
To ensure global food security under the changing climate, there is a strong need for developing ‘climate resilient crops’ that can thrive and produce better yields under extreme environmental conditions such as drought, salinity, and high temperature. To enhance plant productivity under the [...] Read more.
To ensure global food security under the changing climate, there is a strong need for developing ‘climate resilient crops’ that can thrive and produce better yields under extreme environmental conditions such as drought, salinity, and high temperature. To enhance plant productivity under the adverse conditions, we constitutively overexpressed a bifunctional wax synthase/acyl-CoA:diacylglycerol acyltransferase (WSD1) gene, which plays a critical role in wax ester synthesis in Arabidopsis stem and leaf tissues. The qRT-PCR analysis showed a strong upregulation of WSD1 transcripts by mannitol, NaCl, and abscisic acid (ABA) treatments, particularly in Arabidopsis thaliana shoots. Gas chromatography and electron microscopy analyses of Arabidopsis seedlings overexpressing WSD1 showed higher deposition of epicuticular wax crystals and increased leaf and stem wax loading in WSD1 transgenics compared to wildtype (WT) plants. WSD1 transgenics exhibited enhanced tolerance to ABA, mannitol, drought and salinity, which suggested new physiological roles for WSD1 in stress response aside from its wax synthase activity. Transgenic plants were able to recover from drought and salinity better than the WT plants. Furthermore, transgenics showed reduced cuticular transpirational rates and cuticle permeability, as well as less chlorophyll leaching than the WT. The knowledge from Arabidopsis was translated to the oilseed crop Camelina sativa (L.) Crantz. Similar to Arabidopsis, transgenic Camelina lines overexpressing WSD1 also showed enhanced tolerance to drought stress. Our results clearly show that the manipulation of cuticular waxes will be advantageous for enhancing plant productivity under a changing climate. Full article
(This article belongs to the Special Issue Mechanisms of Drought, Temperature and Salinity Tolerance in Plants)
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18 pages, 3526 KiB  
Article
Identification and Characterization of Abiotic Stress Responsive CBL-CIPK Family Genes in Medicago
by Wenxuan Du, Junfeng Yang, Lin Ma, Qian Su and Yongzhen Pang
Int. J. Mol. Sci. 2021, 22(9), 4634; https://0-doi-org.brum.beds.ac.uk/10.3390/ijms22094634 - 28 Apr 2021
Cited by 22 | Viewed by 2509
Abstract
The calcineurin B-like protein (CBL) and CBL-interacting protein kinase (CIPK) play important roles in plant signal transduction and response to abiotic stress. Plants of Medicago genus contain many important forages, and their growth is often affected by a variety of abiotic stresses. However, [...] Read more.
The calcineurin B-like protein (CBL) and CBL-interacting protein kinase (CIPK) play important roles in plant signal transduction and response to abiotic stress. Plants of Medicago genus contain many important forages, and their growth is often affected by a variety of abiotic stresses. However, studies on the CBL and CIPK family member and their function are rare in Medicago. In this study, a total of 23 CBL and 58 CIPK genes were identified from the genome of Medicago sativa as an important forage crop, and Medicaog truncatula as the model plant. Phylogenetic analysis suggested that these CBL and CIPK genes could be classified into five and seven groups, respectively. Moreover, these genes/proteins showed diverse exon-intron organizations, architectures of conserved protein motifs. Many stress-related cis-acting elements were found in their promoter region. In addition, transcriptional analyses showed that these CBL and CIPK genes exhibited distinct expression patterns in various tissues, and in response to drought, salt, and abscisic acid treatments. In particular, the expression levels of MtCIPK2 (MsCIPK3), MtCIPK17 (MsCIPK11), and MtCIPK18 (MsCIPK12) were significantly increased under PEG, NaCl, and ABA treatments. Collectively, our study suggested that CBL and CIPK genes play crucial roles in response to various abiotic stresses in Medicago. Full article
(This article belongs to the Special Issue Mechanisms of Drought, Temperature and Salinity Tolerance in Plants)
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20 pages, 2528 KiB  
Article
Changes in the Flower and Leaf Proteome of Common Buckwheat (Fagopyrum esculentum Moench) under High Temperature
by Przemysław Kopeć, Marta Hornyák, Jakub Pastuszak, Anna Szczerba, Marcin Rapacz, Jacek Waga and Agnieszka Płażek
Int. J. Mol. Sci. 2021, 22(5), 2678; https://0-doi-org.brum.beds.ac.uk/10.3390/ijms22052678 - 06 Mar 2021
Cited by 5 | Viewed by 2716
Abstract
Common buckwheat (Fagopyrum esculentum Moench), a pseudocereal crop, produces a large number of flowers, but this does not guarantee high seed yields. This species demonstrates strong abortion of flowers and embryos. High temperatures during the generative growth phase result in an increase [...] Read more.
Common buckwheat (Fagopyrum esculentum Moench), a pseudocereal crop, produces a large number of flowers, but this does not guarantee high seed yields. This species demonstrates strong abortion of flowers and embryos. High temperatures during the generative growth phase result in an increase in the degeneration of embryo sacs. The aim of this study was to investigate proteomic changes in flowers and leaves of two common buckwheat accessions with different degrees of heat tolerance, Panda and PA15. Two-dimensional gel electrophoresis and mass spectrometry techniques were used to analyze the proteome profiles. Analyses were conducted for flower buds, open flowers capable of fertilization, and wilted flowers, as well as donor leaves, i.e., those growing closest to the inflorescences. High temperature up-regulated the expression of 182 proteins. The proteomic response to heat stress differed between the accessions and among their organs. In the Panda accession, we observed a change in abundance of 17, 13, 28, and 11 proteins, in buds, open and wilted flowers, and leaves, respectively. However, in the PA15 accession there were 34, 21, 63, and 21 such proteins, respectively. Fifteen heat-affected proteins were common to both accessions. The indole-3-glycerol phosphate synthase chloroplastic-like isoform X2 accumulated in the open flowers of the heat-sensitive cultivar Panda in response to high temperature, and may be a candidate protein as a marker of heat sensitivity in buckwheat plants. Full article
(This article belongs to the Special Issue Mechanisms of Drought, Temperature and Salinity Tolerance in Plants)
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23 pages, 45911 KiB  
Article
Differential Morpho-Physiological and Transcriptomic Responses to Heat Stress in Two Blueberry Species
by Jodi Callwood, Kalpalatha Melmaiee, Krishnanand P. Kulkarni, Amaranatha R. Vennapusa, Diarra Aicha, Michael Moore, Nicholi Vorsa, Purushothaman Natarajan, Umesh K. Reddy and Sathya Elavarthi
Int. J. Mol. Sci. 2021, 22(5), 2481; https://0-doi-org.brum.beds.ac.uk/10.3390/ijms22052481 - 01 Mar 2021
Cited by 6 | Viewed by 3797
Abstract
Blueberries (Vaccinium spp.) are highly vulnerable to changing climatic conditions, especially increasing temperatures. To gain insight into mechanisms underpinning the response to heat stress, two blueberry species were subjected to heat stress for 6 and 9 h at 45 °C, and leaf [...] Read more.
Blueberries (Vaccinium spp.) are highly vulnerable to changing climatic conditions, especially increasing temperatures. To gain insight into mechanisms underpinning the response to heat stress, two blueberry species were subjected to heat stress for 6 and 9 h at 45 °C, and leaf samples were used to study the morpho-physiological and transcriptomic changes. As compared with Vaccinium corymbosum, Vaccinium darrowii exhibited thermal stress adaptation features such as small leaf size, parallel leaf orientation, waxy leaf coating, increased stomatal surface area, and stomatal closure. RNAseq analysis yielded ~135 million reads and identified 8305 differentially expressed genes (DEGs) during heat stress against the control samples. In V. corymbosum, 2861 and 4565 genes were differentially expressed at 6 and 9 h of heat stress, whereas in V. darrowii, 2516 and 3072 DEGs were differentially expressed at 6 and 9 h, respectively. Among the pathways, the protein processing in the endoplasmic reticulum (ER) was the highly enriched pathway in both the species: however, certain metabolic, fatty acid, photosynthesis-related, peroxisomal, and circadian rhythm pathways were enriched differently among the species. KEGG enrichment analysis of the DEGs revealed important biosynthesis and metabolic pathways crucial in response to heat stress. The GO terms enriched in both the species under heat stress were similar, but more DEGs were enriched for GO terms in V. darrowii than the V. corymbosum. Together, these results elucidate the differential response of morpho-physiological and molecular mechanisms used by both the blueberry species under heat stress, and help in understanding the complex mechanisms involved in heat stress tolerance. Full article
(This article belongs to the Special Issue Mechanisms of Drought, Temperature and Salinity Tolerance in Plants)
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33 pages, 3145 KiB  
Article
Overexpression of A Biotic Stress-Inducible Pvgstu Gene Activates Early Protective Responses in Tobacco under Combined Heat and Drought
by Evangelia Stavridou, Georgia Voulgari, Michail Michailidis, Stefanos Kostas, Evangelia G. Chronopoulou, Nikolaos E. Labrou, Panagiotis Madesis and Irini Nianiou-Obeidat
Int. J. Mol. Sci. 2021, 22(5), 2352; https://0-doi-org.brum.beds.ac.uk/10.3390/ijms22052352 - 26 Feb 2021
Cited by 11 | Viewed by 3011
Abstract
Drought and heat stresses are major factors limiting crop growth and productivity, and their effect is more devastating when occurring concurrently. Plant glutathione transferases (GSTs) are differentially expressed in response to different stimuli, conferring tolerance to a wide range of abiotic stresses. GSTs [...] Read more.
Drought and heat stresses are major factors limiting crop growth and productivity, and their effect is more devastating when occurring concurrently. Plant glutathione transferases (GSTs) are differentially expressed in response to different stimuli, conferring tolerance to a wide range of abiotic stresses. GSTs from drought-tolerant Phaseolus vulgaris var. “Plake Megalosperma Prespon” is expected to play an important role in the response mechanisms to combined and single heat and drought stresses. Herein, we examined wild-type N. tabacum plants (cv. Basmas Xanthi) and T1 transgenic lines overexpressing the stress-induced Pvgstu3–3 and Pvgstu2–2 genes. The overexpression of Pvgstu3–3 contributed to potential thermotolerance and greater plant performance under combined stress. Significant alterations in the primary metabolism were observed in the transgenic plants between combined stress and stress-free conditions. Stress-responsive differentially expressed genes (DEGs) and transcription factors (TFs) related to photosynthesis, signal transduction, starch and sucrose metabolism, osmotic adjustment and thermotolerance, were identified under combined stress. In contrast, induction of certain DEGs and TF families under stress-free conditions indicated that transgenic plants were in a primed state. The overexpression of the Pvgstu3–3 is playing a leading role in the production of signaling molecules, induction of specific metabolites and activation of the protective mechanisms for enhanced protection against combined abiotic stresses in tobacco. Full article
(This article belongs to the Special Issue Mechanisms of Drought, Temperature and Salinity Tolerance in Plants)
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28 pages, 2616 KiB  
Article
Na+ and/or Cl− Toxicities Determine Salt Sensitivity in Soybean (Glycine max (L.) Merr.), Mungbean (Vigna radiata (L.) R. Wilczek), Cowpea (Vigna unguiculata (L.) Walp.), and Common Bean (Phaseolus vulgaris L.)
by Ly Thi Thanh Le, Lukasz Kotula, Kadambot H. M. Siddique and Timothy D. Colmer
Int. J. Mol. Sci. 2021, 22(4), 1909; https://0-doi-org.brum.beds.ac.uk/10.3390/ijms22041909 - 14 Feb 2021
Cited by 15 | Viewed by 4034
Abstract
Grain legumes are important crops, but they are salt sensitive. This research dissected the responses of four (sub)tropical grain legumes to ionic components (Na+ and/or Cl−) of salt stress. Soybean, mungbean, cowpea, and common bean were subjected to NaCl, Na [...] Read more.
Grain legumes are important crops, but they are salt sensitive. This research dissected the responses of four (sub)tropical grain legumes to ionic components (Na+ and/or Cl−) of salt stress. Soybean, mungbean, cowpea, and common bean were subjected to NaCl, Na+ salts (without Cl−), Cl− salts (without Na+), and a “high cation” negative control for 57 days. Growth, leaf gas exchange, and tissue ion concentrations were assessed at different growing stages. For soybean, NaCl and Na+ salts impaired seed dry mass (30% of control), more so than Cl− salts (60% of control). All treatments impaired mungbean growth, with NaCl and Cl− salt treatments affecting seed dry mass the most (2% of control). For cowpea, NaCl had the greatest adverse impact on seed dry mass (20% of control), while Na+ salts and Cl− salts had similar intermediate effects (~45% of control). For common bean, NaCl had the greatest adverse effect on seed dry mass (4% of control), while Na+ salts and Cl− salts impaired seed dry mass to a lesser extent (~45% of control). NaCl and Na+ salts (without Cl−) affected the photosynthesis (Pn) of soybean more than Cl− salts (without Na+) (50% of control), while the reverse was true for mungbean. Na+ salts (without Cl−), Cl− salts (without Na+), and NaCl had similar adverse effects on Pn of cowpea and common bean (~70% of control). In conclusion, salt sensitivity is predominantly determined by Na+ toxicity in soybean, Cl− toxicity in mungbean, and both Na+ and Cl− toxicity in cowpea and common bean. Full article
(This article belongs to the Special Issue Mechanisms of Drought, Temperature and Salinity Tolerance in Plants)
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33 pages, 12939 KiB  
Article
Stem Photosynthesis—A Key Element of Grass Pea (Lathyrus sativus L.) Acclimatisation to Salinity
by Krzysztof M. Tokarz, Wojciech Wesołowski, Barbara Tokarz, Wojciech Makowski, Anna Wysocka, Roman J. Jędrzejczyk, Karolina Chrabaszcz, Kamilla Malek and Anna Kostecka-Gugała
Int. J. Mol. Sci. 2021, 22(2), 685; https://0-doi-org.brum.beds.ac.uk/10.3390/ijms22020685 - 12 Jan 2021
Cited by 23 | Viewed by 3891
Abstract
Grass pea (Lathyrus sativus) is a leguminous plant of outstanding tolerance to abiotic stress. The aim of the presented study was to describe the mechanism of grass pea (Lathyrus sativus L.) photosynthetic apparatus acclimatisation strategies to salinity stress. The seedlings [...] Read more.
Grass pea (Lathyrus sativus) is a leguminous plant of outstanding tolerance to abiotic stress. The aim of the presented study was to describe the mechanism of grass pea (Lathyrus sativus L.) photosynthetic apparatus acclimatisation strategies to salinity stress. The seedlings were cultivated in a hydroponic system in media containing various concentrations of NaCl (0, 50, and 100 mM), imitating none, moderate, and severe salinity, respectively, for three weeks. In order to characterise the function and structure of the photosynthetic apparatus, Chl a fluorescence, gas exchange measurements, proteome analysis, and Fourier-transform infrared spectroscopy (FT-IR) analysis were done inter alia. Significant differences in the response of the leaf and stem photosynthetic apparatus to severe salt stress were observed. Leaves became the place of harmful ion (Na+) accumulation, and the efficiency of their carboxylation decreased sharply. In turn, in stems, the reconstruction of the photosynthetic apparatus (antenna and photosystem complexes) activated alternative electron transport pathways, leading to effective ATP synthesis, which is required for the efficient translocation of Na+ to leaves. These changes enabled efficient stem carboxylation and made them the main source of assimilates. The observed changes indicate the high plasticity of grass pea photosynthetic apparatus, providing an effective mechanism of tolerance to salinity stress. Full article
(This article belongs to the Special Issue Mechanisms of Drought, Temperature and Salinity Tolerance in Plants)
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22 pages, 5441 KiB  
Article
Salinity Effects on Guard Cell Proteome in Chenopodium quinoa
by Fatemeh Rasouli, Ali Kiani-Pouya, Lana Shabala, Leiting Li, Ayesha Tahir, Min Yu, Rainer Hedrich, Zhonghua Chen, Richard Wilson, Heng Zhang and Sergey Shabala
Int. J. Mol. Sci. 2021, 22(1), 428; https://0-doi-org.brum.beds.ac.uk/10.3390/ijms22010428 - 04 Jan 2021
Cited by 18 | Viewed by 3453
Abstract
Epidermal fragments enriched in guard cells (GCs) were isolated from the halophyte quinoa (Chenopodium quinoa Wild.) species, and the response at the proteome level was studied after salinity treatment of 300 mM NaCl for 3 weeks. In total, 2147 proteins were identified, [...] Read more.
Epidermal fragments enriched in guard cells (GCs) were isolated from the halophyte quinoa (Chenopodium quinoa Wild.) species, and the response at the proteome level was studied after salinity treatment of 300 mM NaCl for 3 weeks. In total, 2147 proteins were identified, of which 36% were differentially expressed in response to salinity stress in GCs. Up and downregulated proteins included signaling molecules, enzyme modulators, transcription factors and oxidoreductases. The most abundant proteins induced by salt treatment were desiccation-responsive protein 29B (50-fold), osmotin-like protein OSML13 (13-fold), polycystin-1, lipoxygenase, alpha-toxin, and triacylglycerol lipase (PLAT) domain-containing protein 3-like (eight-fold), and dehydrin early responsive to dehydration (ERD14) (eight-fold). Ten proteins related to the gene ontology term “response to ABA” were upregulated in quinoa GC; this included aspartic protease, phospholipase D and plastid-lipid-associated protein. Additionally, seven proteins in the sucrose–starch pathway were upregulated in the GC in response to salinity stress, and accumulation of tryptophan synthase and L-methionine synthase (enzymes involved in the amino acid biosynthesis) was observed. Exogenous application of sucrose and tryptophan, L-methionine resulted in reduction in stomatal aperture and conductance, which could be advantageous for plants under salt stress. Eight aspartic proteinase proteins were highly upregulated in GCs of quinoa, and exogenous application of pepstatin A (an inhibitor of aspartic proteinase) was accompanied by higher oxidative stress and extremely low stomatal aperture and conductance, suggesting a possible role of aspartic proteinase in mitigating oxidative stress induced by saline conditions. Full article
(This article belongs to the Special Issue Mechanisms of Drought, Temperature and Salinity Tolerance in Plants)
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17 pages, 1748 KiB  
Article
Distinct Preflowering Drought Tolerance Strategies of Sorghum bicolor Genotype RTx430 Revealed by Subcellular Protein Profiling
by Aaron J. Ogden, Shadan Abdali, Kristin M. Engbrecht, Mowei Zhou and Pubudu P. Handakumbura
Int. J. Mol. Sci. 2020, 21(24), 9706; https://0-doi-org.brum.beds.ac.uk/10.3390/ijms21249706 - 19 Dec 2020
Cited by 9 | Viewed by 2496
Abstract
Drought is the largest stress affecting agricultural crops, resulting in substantial reductions in yield. Plant adaptation to water stress is a complex trait involving changes in hormone signaling, physiology, and morphology. Sorghum (Sorghum bicolor (L.) Moench) is a C4 cereal grass; it [...] Read more.
Drought is the largest stress affecting agricultural crops, resulting in substantial reductions in yield. Plant adaptation to water stress is a complex trait involving changes in hormone signaling, physiology, and morphology. Sorghum (Sorghum bicolor (L.) Moench) is a C4 cereal grass; it is an agricultural staple, and it is particularly drought-tolerant. To better understand drought adaptation strategies, we compared the cytosolic- and organelle-enriched protein profiles of leaves from two Sorghum bicolor genotypes, RTx430 and BTx642, with differing preflowering drought tolerances after 8 weeks of growth under water limitation in the field. In agreement with previous findings, we observed significant drought-induced changes in the abundance of multiple heat shock proteins and dehydrins in both genotypes. Interestingly, our data suggest a larger genotype-specific drought response in protein profiles of organelles, while cytosolic responses are largely similar between genotypes. Organelle-enriched proteins whose abundance significantly changed exclusively in the preflowering drought-tolerant genotype RTx430 upon drought stress suggest multiple mechanisms of drought tolerance. These include an RTx430-specific change in proteins associated with ABA metabolism and signal transduction, Rubisco activation, reactive oxygen species scavenging, flowering time regulation, and epicuticular wax production. We discuss the current understanding of these processes in relation to drought tolerance and their potential implications. Full article
(This article belongs to the Special Issue Mechanisms of Drought, Temperature and Salinity Tolerance in Plants)
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21 pages, 4406 KiB  
Article
Genome-Wide Gene Expression Profiles Analysis Reveal Novel Insights into Drought Stress in Foxtail Millet (Setaria italica L.)
by Ling Qin, Erying Chen, Feifei Li, Xiao Yu, Zhenyu Liu, Yanbing Yang, Runfeng Wang, Huawen Zhang, Hailian Wang, Bin Liu, Yan’an Guan and Ying Ruan
Int. J. Mol. Sci. 2020, 21(22), 8520; https://0-doi-org.brum.beds.ac.uk/10.3390/ijms21228520 - 12 Nov 2020
Cited by 16 | Viewed by 3022
Abstract
Foxtail millet (Setaria italica (L.) P. Beauv) is an important food and forage crop because of its health benefits and adaptation to drought stress; however, reports of transcriptomic analysis of genes responding to re-watering after drought stress in foxtail millet are rare. [...] Read more.
Foxtail millet (Setaria italica (L.) P. Beauv) is an important food and forage crop because of its health benefits and adaptation to drought stress; however, reports of transcriptomic analysis of genes responding to re-watering after drought stress in foxtail millet are rare. The present study evaluated physiological parameters, such as proline content, p5cs enzyme activity, anti-oxidation enzyme activities, and investigated gene expression patterns using RNA sequencing of the drought-tolerant foxtail millet variety (Jigu 16) treated with drought stress and rehydration. The results indicated that drought stress-responsive genes were related to many multiple metabolic processes, such as photosynthesis, signal transduction, phenylpropanoid biosynthesis, starch and sucrose metabolism, and osmotic adjustment. Furthermore, the Δ1-pyrroline-5-carboxylate synthetase genes, SiP5CS1 and SiP5CS2, were remarkably upregulated in foxtail millet under drought stress conditions. Foxtail millet can also recover well on rehydration after drought stress through gene regulation. Our data demonstrate that recovery on rehydration primarily involves proline metabolism, sugar metabolism, hormone signal transduction, water transport, and detoxification, plus reversal of the expression direction of most drought-responsive genes. Our results provided a detailed description of the comparative transcriptome response of foxtail millet variety Jigu 16 under drought and rehydration environments. Furthermore, we identify SiP5CS2 as an important gene likely involved in the drought tolerance of foxtail millet. Full article
(This article belongs to the Special Issue Mechanisms of Drought, Temperature and Salinity Tolerance in Plants)
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17 pages, 5585 KiB  
Article
AcoMYB4, an Ananas comosus L. MYB Transcription Factor, Functions in Osmotic Stress through Negative Regulation of ABA Signaling
by Huihuang Chen, Linyi Lai, Lanxin Li, Liping Liu, Bello Hassan Jakada, Youmei Huang, Qing He, Mengnan Chai, Xiaoping Niu and Yuan Qin
Int. J. Mol. Sci. 2020, 21(16), 5727; https://0-doi-org.brum.beds.ac.uk/10.3390/ijms21165727 - 10 Aug 2020
Cited by 24 | Viewed by 3054
Abstract
Drought and salt stress are the main environmental cues affecting the survival, development, distribution, and yield of crops worldwide. MYB transcription factors play a crucial role in plants’ biological processes, but the function of pineapple MYB genes is still obscure. In this study, [...] Read more.
Drought and salt stress are the main environmental cues affecting the survival, development, distribution, and yield of crops worldwide. MYB transcription factors play a crucial role in plants’ biological processes, but the function of pineapple MYB genes is still obscure. In this study, one of the pineapple MYB transcription factors, AcoMYB4, was isolated and characterized. The results showed that AcoMYB4 is localized in the cell nucleus, and its expression is induced by low temperature, drought, salt stress, and hormonal stimulation, especially by abscisic acid (ABA). Overexpression of AcoMYB4 in rice and Arabidopsis enhanced plant sensitivity to osmotic stress; it led to an increase in the number stomata on leaf surfaces and lower germination rate under salt and drought stress. Furthermore, in AcoMYB4 OE lines, the membrane oxidation index, free proline, and soluble sugar contents were decreased. In contrast, electrolyte leakage and malondialdehyde (MDA) content increased significantly due to membrane injury, indicating higher sensitivity to drought and salinity stresses. Besides the above, both the expression level and activities of several antioxidant enzymes were decreased, indicating lower antioxidant activity in AcoMYB4 transgenic plants. Moreover, under osmotic stress, overexpression of AcoMYB4 inhibited ABA biosynthesis through a decrease in the transcription of genes responsible for ABA synthesis (ABA1 and ABA2) and ABA signal transduction factor ABI5. These results suggest that AcoMYB4 negatively regulates osmotic stress by attenuating cellular ABA biosynthesis and signal transduction pathways. Full article
(This article belongs to the Special Issue Mechanisms of Drought, Temperature and Salinity Tolerance in Plants)
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17 pages, 678 KiB  
Article
Genetic Dissection and Identification of Candidate Genes for Salinity Tolerance Using Axiom®CicerSNP Array in Chickpea
by Khela Ram Soren, Praveen Madugula, Neeraj Kumar, Rutwik Barmukh, Meenu Singh Sengar, Chellapilla Bharadwaj, Parbodh Chander Sharma, Sarvjeet Singh, Aditi Bhandari, Jogendra Singh, Satish Kumar Sanwal, Madan Pal, Sneha Priya P.R., Anita Mann, Someswar Rao Sagurthi, Shanmugavadivel PS, Kadambot H.M. Siddique, Narendra Pratap Singh, Manish Roorkiwal and Rajeev K Varshney
Int. J. Mol. Sci. 2020, 21(14), 5058; https://0-doi-org.brum.beds.ac.uk/10.3390/ijms21145058 - 17 Jul 2020
Cited by 35 | Viewed by 5418
Abstract
Globally, chickpea production is severely affected by salinity stress. Understanding the genetic basis for salinity tolerance is important to develop salinity tolerant chickpeas. A recombinant inbred line (RIL) population developed using parental lines ICCV 10 (salt-tolerant) and DCP 92-3 (salt-sensitive) was screened under [...] Read more.
Globally, chickpea production is severely affected by salinity stress. Understanding the genetic basis for salinity tolerance is important to develop salinity tolerant chickpeas. A recombinant inbred line (RIL) population developed using parental lines ICCV 10 (salt-tolerant) and DCP 92-3 (salt-sensitive) was screened under field conditions to collect information on agronomy, yield components, and stress tolerance indices. Genotyping data generated using Axiom®CicerSNP array was used to construct a linkage map comprising 1856 SNP markers spanning a distance of 1106.3 cM across eight chickpea chromosomes. Extensive analysis of the phenotyping and genotyping data identified 28 quantitative trait loci (QTLs) explaining up to 28.40% of the phenotypic variance in the population. We identified QTL clusters on CaLG03 and CaLG06, each harboring major QTLs for yield and yield component traits under salinity stress. The main-effect QTLs identified in these two clusters were associated with key genes such as calcium-dependent protein kinases, histidine kinases, cation proton antiporter, and WRKY and MYB transcription factors, which are known to impart salinity stress tolerance in crop plants. Molecular markers/genes associated with these major QTLs, after validation, will be useful to undertake marker-assisted breeding for developing better varieties with salinity tolerance. Full article
(This article belongs to the Special Issue Mechanisms of Drought, Temperature and Salinity Tolerance in Plants)
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16 pages, 4357 KiB  
Article
Effect of Heat Stress on Seed Protein Composition and Ultrastructure of Protein Storage Vacuoles in the Cotyledonary Parenchyma Cells of Soybean Genotypes That Are Either Tolerant or Sensitive to Elevated Temperatures
by Hari B. Krishnan, Won-Seok Kim, Nathan W. Oehrle, James R. Smith and Jason D. Gillman
Int. J. Mol. Sci. 2020, 21(13), 4775; https://0-doi-org.brum.beds.ac.uk/10.3390/ijms21134775 - 05 Jul 2020
Cited by 22 | Viewed by 3794
Abstract
High growth temperatures negatively affect soybean (Glycine max (L.) Merr) yields and seed quality. Soybean plants, heat stressed during seed development, produce seed that exhibit wrinkling, discoloration, poor seed germination, and have an increased potential for incidence of pathogen infection and an [...] Read more.
High growth temperatures negatively affect soybean (Glycine max (L.) Merr) yields and seed quality. Soybean plants, heat stressed during seed development, produce seed that exhibit wrinkling, discoloration, poor seed germination, and have an increased potential for incidence of pathogen infection and an overall decrease in economic value. Soybean breeders have identified a heat stress tolerant exotic landrace genotype, which has been used in traditional hybridization to generate experimental genotypes, with improved seed yield and heat tolerance. Here, we have investigated the seed protein composition and ultrastructure of cotyledonary parenchyma cells of soybean genotypes that are either susceptible or tolerant to high growth temperatures. Biochemical analyses of seed proteins isolated from heat-tolerant and heat-sensitive genotypes produced under 28/22 °C (control), 36/24 °C (moderate), and 42/26 °C (extreme) day/night temperatures revealed that the accumulation in soybean seeds of lipoxygenase, the β-subunit of β-conglycinin, sucrose binding protein and Bowman-Birk protease inhibitor were negatively impacted by extreme heat stress in both genotypes, but these effects were less pronounced in the heat-tolerant genotype. Western blot analysis showed elevated accumulation of heat shock proteins (HSP70 and HSP17.6) in both lines in response to elevated temperatures during seed fill. Transmission electron microscopy showed that heat stress caused dramatic structural changes in the storage parenchyma cells. Extreme heat stress disrupted the structure and the membrane integrity of protein storage vacuoles, organelles that accumulate seed storage proteins. The detachment of the plasma membrane from the cell wall (plasmolysis) was commonly observed in the cells of the sensitive line. In contrast, these structural changes were less pronounced in the tolerant genotype, even under extreme heat stress, cells, for the most part, retained their structural integrity. The results of our study demonstrate the contrasting effects of heat stress on the seed protein composition and ultrastructural alterations that contribute to the tolerant genotype’s ability to tolerate high temperatures during seed development. Full article
(This article belongs to the Special Issue Mechanisms of Drought, Temperature and Salinity Tolerance in Plants)
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24 pages, 7402 KiB  
Article
Autophagy-Related 2 Regulates Chlorophyll Degradation under Abiotic Stress Conditions in Arabidopsis
by Zhuanzhuan Jiang, Li Zhu, Qiuyu Wang and Xin Hou
Int. J. Mol. Sci. 2020, 21(12), 4515; https://0-doi-org.brum.beds.ac.uk/10.3390/ijms21124515 - 25 Jun 2020
Cited by 21 | Viewed by 3450
Abstract
Chloroplasts are extraordinary organelles for photosynthesis and nutrient storage in plants. During leaf senescence or under stress conditions, damaged chloroplasts are degraded and provide nutrients for developing organs. Autophagy is a high-throughput degradation pathway for intracellular material turnover in eukaryotes. Along with chloroplast [...] Read more.
Chloroplasts are extraordinary organelles for photosynthesis and nutrient storage in plants. During leaf senescence or under stress conditions, damaged chloroplasts are degraded and provide nutrients for developing organs. Autophagy is a high-throughput degradation pathway for intracellular material turnover in eukaryotes. Along with chloroplast degradation, chlorophyll, an important component of the photosynthetic machine, is also degraded. However, the chlorophyll degradation pathways under high light intensity and high temperature stress are not well known. Here, we identified and characterized a novel Arabidopsis mutant, sl2 (seedling lethal 2), showing defective chloroplast development and accelerated chlorophyll degradation. Map-based cloning combined with high-throughput sequencing analysis revealed that a 118.6 kb deletion region was associated with the phenotype of the mutant. Complementary experiments confirmed that the loss of function of ATG2 was responsible for accelerating chlorophyll degradation in sl2 mutants. Furthermore, we analyzed chlorophyll degradation under abiotic stress conditions and found that both chloroplast vesiculation and autophagy take part in chlorophyll degradation under high light intensity and high temperature stress. These results enhanced our understanding of chlorophyll degradation under high light intensity and high temperature stress. Full article
(This article belongs to the Special Issue Mechanisms of Drought, Temperature and Salinity Tolerance in Plants)
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Review

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16 pages, 3243 KiB  
Review
Candidate Genes and Pathways in Rice Co-Responding to Drought and Salt Identified by gcHap Network
by Zhiqi Hao, Sai Ma, Lunping Liang, Ting Feng, Mengyuan Xiong, Shangshu Lian, Jingyan Zhu, Yanjun Chen, Lijun Meng and Min Li
Int. J. Mol. Sci. 2022, 23(7), 4016; https://0-doi-org.brum.beds.ac.uk/10.3390/ijms23074016 - 05 Apr 2022
Cited by 4 | Viewed by 2786
Abstract
Drought and salinity stresses are significant abiotic factors that limit rice yield. Exploring the co-response mechanism to drought and salt stress will be conducive to future rice breeding. A total of 1748 drought and salt co-responsive genes were screened, most of which are [...] Read more.
Drought and salinity stresses are significant abiotic factors that limit rice yield. Exploring the co-response mechanism to drought and salt stress will be conducive to future rice breeding. A total of 1748 drought and salt co-responsive genes were screened, most of which are enriched in plant hormone signal transduction, protein processing in the endoplasmic reticulum, and the MAPK signaling pathways. We performed gene-coding sequence haplotype (gcHap) network analysis on nine important genes out of the total amount, which showed significant differences between the Xian/indica and Geng/japonica population. These genes were combined with related pathways, resulting in an interesting mechanistic draft called the ‘gcHap-network pathway’. Meanwhile, we collected a lot of drought and salt breeding varieties, especially the introgression lines (ILs) with HHZ as the parent, which contained the above-mentioned nine genes. This might imply that these ILs have the potential to improve the tolerance to drought and salt. In this paper, we focus on the relationship of drought and salt co-response gene gcHaps and their related pathways using a novel angle. The haplotype network will be helpful to explore the desired haplotypes that can be implemented in haplotype-based breeding programs. Full article
(This article belongs to the Special Issue Mechanisms of Drought, Temperature and Salinity Tolerance in Plants)
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32 pages, 2428 KiB  
Review
Impacts, Tolerance, Adaptation, and Mitigation of Heat Stress on Wheat under Changing Climates
by Malu Ram Yadav, Mukesh Choudhary, Jogendra Singh, Milan Kumar Lal, Prakash Kumar Jha, Pushpika Udawat, Narendra Kumar Gupta, Vishnu D. Rajput, Nitin Kumar Garg, Chirag Maheshwari, Muzaffar Hasan, Sunita Gupta, Tarun Kumar Jatwa, Rakesh Kumar, Arvind Kumar Yadav and P. V. Vara Prasad
Int. J. Mol. Sci. 2022, 23(5), 2838; https://0-doi-org.brum.beds.ac.uk/10.3390/ijms23052838 - 04 Mar 2022
Cited by 51 | Viewed by 10495
Abstract
Heat stress (HS) is one of the major abiotic stresses affecting the production and quality of wheat. Rising temperatures are particularly threatening to wheat production. A detailed overview of morpho-physio-biochemical responses of wheat to HS is critical to identify various tolerance mechanisms and [...] Read more.
Heat stress (HS) is one of the major abiotic stresses affecting the production and quality of wheat. Rising temperatures are particularly threatening to wheat production. A detailed overview of morpho-physio-biochemical responses of wheat to HS is critical to identify various tolerance mechanisms and their use in identifying strategies to safeguard wheat production under changing climates. The development of thermotolerant wheat cultivars using conventional or molecular breeding and transgenic approaches is promising. Over the last decade, different omics approaches have revolutionized the way plant breeders and biotechnologists investigate underlying stress tolerance mechanisms and cellular homeostasis. Therefore, developing genomics, transcriptomics, proteomics, and metabolomics data sets and a deeper understanding of HS tolerance mechanisms of different wheat cultivars are needed. The most reliable method to improve plant resilience to HS must include agronomic management strategies, such as the adoption of climate-smart cultivation practices and use of osmoprotectants and cultured soil microbes. However, looking at the complex nature of HS, the adoption of a holistic approach integrating outcomes of breeding, physiological, agronomical, and biotechnological options is required. Our review aims to provide insights concerning morpho-physiological and molecular impacts, tolerance mechanisms, and adaptation strategies of HS in wheat. This review will help scientific communities in the identification, development, and promotion of thermotolerant wheat cultivars and management strategies to minimize negative impacts of HS. Full article
(This article belongs to the Special Issue Mechanisms of Drought, Temperature and Salinity Tolerance in Plants)
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35 pages, 4163 KiB  
Review
How to Cope with the Challenges of Environmental Stresses in the Era of Global Climate Change: An Update on ROS Stave off in Plants
by Archana Singh, Sahil Mehta, Sunita Yadav, Garima Nagar, Rajgourab Ghosh, Amit Roy, Amrita Chakraborty and Indrakant K. Singh
Int. J. Mol. Sci. 2022, 23(4), 1995; https://0-doi-org.brum.beds.ac.uk/10.3390/ijms23041995 - 11 Feb 2022
Cited by 49 | Viewed by 3985
Abstract
With the advent of human civilization and anthropogenic activities in the shade of urbanization and global climate change, plants are exposed to a complex set of abiotic stresses. These stresses affect plants’ growth, development, and yield and cause enormous crop losses worldwide. In [...] Read more.
With the advent of human civilization and anthropogenic activities in the shade of urbanization and global climate change, plants are exposed to a complex set of abiotic stresses. These stresses affect plants’ growth, development, and yield and cause enormous crop losses worldwide. In this alarming scenario of global climate conditions, plants respond to such stresses through a highly balanced and finely tuned interaction between signaling molecules. The abiotic stresses initiate the quick release of reactive oxygen species (ROS) as toxic by-products of altered aerobic metabolism during different stress conditions at the cellular level. ROS includes both free oxygen radicals {superoxide (O2•−) and hydroxyl (OH−)} as well as non-radicals [hydrogen peroxide (H2O2) and singlet oxygen (1O2)]. ROS can be generated and scavenged in different cell organelles and cytoplasm depending on the type of stimulus. At high concentrations, ROS cause lipid peroxidation, DNA damage, protein oxidation, and necrosis, but at low to moderate concentrations, they play a crucial role as secondary messengers in intracellular signaling cascades. Because of their concentration-dependent dual role, a huge number of molecules tightly control the level of ROS in cells. The plants have evolved antioxidants and scavenging machinery equipped with different enzymes to maintain the equilibrium between the production and detoxification of ROS generated during stress. In this present article, we have focused on current insights on generation and scavenging of ROS during abiotic stresses. Moreover, the article will act as a knowledge base for new and pivotal studies on ROS generation and scavenging. Full article
(This article belongs to the Special Issue Mechanisms of Drought, Temperature and Salinity Tolerance in Plants)
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26 pages, 2433 KiB  
Review
Genomics Associated Interventions for Heat Stress Tolerance in Cool Season Adapted Grain Legumes
by Jitendra Kumar, Reyazul Rouf Mir, Safoora Shafi, Debjyoti Sen Gupta, Ivica Djalovic, Jegor Miladinovic, Rahul Kumar, Sachin Kumar and Rajeev Kumar
Int. J. Mol. Sci. 2022, 23(1), 399; https://0-doi-org.brum.beds.ac.uk/10.3390/ijms23010399 - 30 Dec 2021
Cited by 6 | Viewed by 3366
Abstract
Cool season grain legumes occupy an important place among the agricultural crops and essentially provide multiple benefits including food supply, nutrition security, soil fertility improvement and revenue for farmers all over the world. However, owing to climate change, the average temperature is steadily [...] Read more.
Cool season grain legumes occupy an important place among the agricultural crops and essentially provide multiple benefits including food supply, nutrition security, soil fertility improvement and revenue for farmers all over the world. However, owing to climate change, the average temperature is steadily rising, which negatively affects crop performance and limits their yield. Terminal heat stress that mainly occurred during grain development phases severely harms grain quality and weight in legumes adapted to the cool season, such as lentils, faba beans, chickpeas, field peas, etc. Although, traditional breeding approaches with advanced screening procedures have been employed to identify heat tolerant legume cultivars. Unfortunately, traditional breeding pipelines alone are no longer enough to meet global demands. Genomics-assisted interventions including new-generation sequencing technologies and genotyping platforms have facilitated the development of high-resolution molecular maps, QTL/gene discovery and marker-assisted introgression, thereby improving the efficiency in legumes breeding to develop stress-resilient varieties. Based on the current scenario, we attempted to review the intervention of genomics to decipher different components of tolerance to heat stress and future possibilities of using newly developed genomics-based interventions in cool season adapted grain legumes. Full article
(This article belongs to the Special Issue Mechanisms of Drought, Temperature and Salinity Tolerance in Plants)
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36 pages, 571 KiB  
Review
The Adaptation and Tolerance of Major Cereals and Legumes to Important Abiotic Stresses
by Jagadish Rane, Ajay Kumar Singh, Mahesh Kumar, Karnar M. Boraiah, Kamlesh K. Meena, Aliza Pradhan and P. V. Vara Prasad
Int. J. Mol. Sci. 2021, 22(23), 12970; https://0-doi-org.brum.beds.ac.uk/10.3390/ijms222312970 - 30 Nov 2021
Cited by 23 | Viewed by 4132
Abstract
Abiotic stresses, including drought, extreme temperatures, salinity, and waterlogging, are the major constraints in crop production. These abiotic stresses are likely to be amplified by climate change with varying temporal and spatial dimensions across the globe. The knowledge about the effects of abiotic [...] Read more.
Abiotic stresses, including drought, extreme temperatures, salinity, and waterlogging, are the major constraints in crop production. These abiotic stresses are likely to be amplified by climate change with varying temporal and spatial dimensions across the globe. The knowledge about the effects of abiotic stressors on major cereal and legume crops is essential for effective management in unfavorable agro-ecologies. These crops are critical components of cropping systems and the daily diets of millions across the globe. Major cereals like rice, wheat, and maize are highly vulnerable to abiotic stresses, while many grain legumes are grown in abiotic stress-prone areas. Despite extensive investigations, abiotic stress tolerance in crop plants is not fully understood. Current insights into the abiotic stress responses of plants have shown the potential to improve crop tolerance to abiotic stresses. Studies aimed at stress tolerance mechanisms have resulted in the elucidation of traits associated with tolerance in plants, in addition to the molecular control of stress-responsive genes. Some of these studies have paved the way for new opportunities to address the molecular basis of stress responses in plants and identify novel traits and associated genes for the genetic improvement of crop plants. The present review examines the responses of crops under abiotic stresses in terms of changes in morphology, physiology, and biochemistry, focusing on major cereals and legume crops. It also explores emerging opportunities to accelerate our efforts to identify desired traits and genes associated with stress tolerance. Full article
(This article belongs to the Special Issue Mechanisms of Drought, Temperature and Salinity Tolerance in Plants)
37 pages, 1352 KiB  
Review
Non-Coding RNAs in Response to Drought Stress
by Temesgen Assefa Gelaw and Neeti Sanan-Mishra
Int. J. Mol. Sci. 2021, 22(22), 12519; https://0-doi-org.brum.beds.ac.uk/10.3390/ijms222212519 - 20 Nov 2021
Cited by 28 | Viewed by 4716
Abstract
Drought stress causes changes in the morphological, physiological, biochemical and molecular characteristics of plants. The response to drought in different plants may vary from avoidance, tolerance and escape to recovery from stress. This response is genetically programmed and regulated in a very complex [...] Read more.
Drought stress causes changes in the morphological, physiological, biochemical and molecular characteristics of plants. The response to drought in different plants may vary from avoidance, tolerance and escape to recovery from stress. This response is genetically programmed and regulated in a very complex yet synchronized manner. The crucial genetic regulations mediated by non-coding RNAs (ncRNAs) have emerged as game-changers in modulating the plant responses to drought and other abiotic stresses. The ncRNAs interact with their targets to form potentially subtle regulatory networks that control multiple genes to determine the overall response of plants. Many long and small drought-responsive ncRNAs have been identified and characterized in different plant varieties. The miRNA-based research is better documented, while lncRNA and transposon-derived RNAs are relatively new, and their cellular role is beginning to be understood. In this review, we have compiled the information on the categorization of non-coding RNAs based on their biogenesis and function. We also discuss the available literature on the role of long and small non-coding RNAs in mitigating drought stress in plants. Full article
(This article belongs to the Special Issue Mechanisms of Drought, Temperature and Salinity Tolerance in Plants)
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25 pages, 1272 KiB  
Review
Drought and High Temperature Stress in Sorghum: Physiological, Genetic, and Molecular Insights and Breeding Approaches
by V. B. Rajendra Prasad, Mahalingam Govindaraj, Maduraimuthu Djanaguiraman, Ivica Djalovic, Anjali Shailani, Nishtha Rawat, Sneh Lata Singla-Pareek, Ashwani Pareek and P. V. Vara Prasad
Int. J. Mol. Sci. 2021, 22(18), 9826; https://0-doi-org.brum.beds.ac.uk/10.3390/ijms22189826 - 11 Sep 2021
Cited by 44 | Viewed by 4913
Abstract
Sorghum is one of the staple crops for millions of people in Sub-Saharan Africa (SSA) and South Asia (SA). The future climate in these sorghum production regions is likely to have unexpected short or long episodes of drought and/or high temperature (HT), which [...] Read more.
Sorghum is one of the staple crops for millions of people in Sub-Saharan Africa (SSA) and South Asia (SA). The future climate in these sorghum production regions is likely to have unexpected short or long episodes of drought and/or high temperature (HT), which can cause significant yield losses. Therefore, to achieve food and nutritional security, drought and HT stress tolerance ability in sorghum must be genetically improved. Drought tolerance mechanism, stay green, and grain yield under stress has been widely studied. However, novel traits associated with drought (restricted transpiration and root architecture) need to be explored and utilized in breeding. In sorghum, knowledge on the traits associated with HT tolerance is limited. Heat shock transcription factors, dehydrins, and genes associated with hormones such as auxin, ethylene, and abscisic acid and compatible solutes are involved in drought stress modulation. In contrast, our understanding of HT tolerance at the omic level is limited and needs attention. Breeding programs have exploited limited traits with narrow genetic and genomic resources to develop drought or heat tolerant lines. Reproductive stages of sorghum are relatively more sensitive to stress compared to vegetative stages. Therefore, breeding should incorporate appropriate pre-flowering and post-flowering tolerance in a broad genetic base population and in heterotic hybrid breeding pipelines. Currently, more than 240 QTLs are reported for drought tolerance-associated traits in sorghum prospecting discovery of trait markers. Identifying traits and better understanding of physiological and genetic mechanisms and quantification of genetic variability for these traits may enhance HT tolerance. Drought and HT tolerance can be improved by better understanding mechanisms associated with tolerance and screening large germplasm collections to identify tolerant lines and incorporation of those traits into elite breeding lines. Systems approaches help in identifying the best donors of tolerance to be incorporated in the SSA and SA sorghum breeding programs. Integrated breeding with use of high-throughput precision phenomics and genomics can deliver a range of drought and HT tolerant genotypes that can improve yield and resilience of sorghum under drought and HT stresses. Full article
(This article belongs to the Special Issue Mechanisms of Drought, Temperature and Salinity Tolerance in Plants)
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22 pages, 1429 KiB  
Review
Role of Reactive Oxygen Species and Hormones in Plant Responses to Temperature Changes
by Amith R. Devireddy, Timothy J. Tschaplinski, Gerald A. Tuskan, Wellington Muchero and Jin-Gui Chen
Int. J. Mol. Sci. 2021, 22(16), 8843; https://0-doi-org.brum.beds.ac.uk/10.3390/ijms22168843 - 17 Aug 2021
Cited by 68 | Viewed by 5815
Abstract
Temperature stress is one of the major abiotic stresses that adversely affect agricultural productivity worldwide. Temperatures beyond a plant’s physiological optimum can trigger significant physiological and biochemical perturbations, reducing plant growth and tolerance to stress. Improving a plant’s tolerance to these temperature fluctuations [...] Read more.
Temperature stress is one of the major abiotic stresses that adversely affect agricultural productivity worldwide. Temperatures beyond a plant’s physiological optimum can trigger significant physiological and biochemical perturbations, reducing plant growth and tolerance to stress. Improving a plant’s tolerance to these temperature fluctuations requires a deep understanding of its responses to environmental change. To adapt to temperature fluctuations, plants tailor their acclimatory signal transduction events, and specifically, cellular redox state, that are governed by plant hormones, reactive oxygen species (ROS) regulatory systems, and other molecular components. The role of ROS in plants as important signaling molecules during stress acclimation has recently been established. Here, hormone-triggered ROS produced by NADPH oxidases, feedback regulation, and integrated signaling events during temperature stress activate stress-response pathways and induce acclimation or defense mechanisms. At the other extreme, excess ROS accumulation, following temperature-induced oxidative stress, can have negative consequences on plant growth and stress acclimation. The excessive ROS is regulated by the ROS scavenging system, which subsequently promotes plant tolerance. All these signaling events, including crosstalk between hormones and ROS, modify the plant’s transcriptomic, metabolomic, and biochemical states and promote plant acclimation, tolerance, and survival. Here, we provide a comprehensive review of the ROS, hormones, and their joint role in shaping a plant’s responses to high and low temperatures, and we conclude by outlining hormone/ROS-regulated plant responsive strategies for developing stress-tolerant crops to combat temperature changes. Full article
(This article belongs to the Special Issue Mechanisms of Drought, Temperature and Salinity Tolerance in Plants)
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26 pages, 1766 KiB  
Review
Elucidating the Response of Crop Plants towards Individual, Combined and Sequentially Occurring Abiotic Stresses
by Khalid Anwar, Rohit Joshi, Om Parkash Dhankher, Sneh L. Singla-Pareek and Ashwani Pareek
Int. J. Mol. Sci. 2021, 22(11), 6119; https://0-doi-org.brum.beds.ac.uk/10.3390/ijms22116119 - 06 Jun 2021
Cited by 34 | Viewed by 4786
Abstract
In nature, plants are exposed to an ever-changing environment with increasing frequencies of multiple abiotic stresses. These abiotic stresses act either in combination or sequentially, thereby driving vegetation dynamics and limiting plant growth and productivity worldwide. Plants’ responses against these combined and sequential [...] Read more.
In nature, plants are exposed to an ever-changing environment with increasing frequencies of multiple abiotic stresses. These abiotic stresses act either in combination or sequentially, thereby driving vegetation dynamics and limiting plant growth and productivity worldwide. Plants’ responses against these combined and sequential stresses clearly differ from that triggered by an individual stress. Until now, experimental studies were mainly focused on plant responses to individual stress, but have overlooked the complex stress response generated in plants against combined or sequential abiotic stresses, as well as their interaction with each other. However, recent studies have demonstrated that the combined and sequential abiotic stresses overlap with respect to the central nodes of their interacting signaling pathways, and their impact cannot be modelled by swimming in an individual extreme event. Taken together, deciphering the regulatory networks operative between various abiotic stresses in agronomically important crops will contribute towards designing strategies for the development of plants with tolerance to multiple stress combinations. This review provides a brief overview of the recent developments in the interactive effects of combined and sequentially occurring stresses on crop plants. We believe that this study may improve our understanding of the molecular and physiological mechanisms in untangling the combined stress tolerance in plants, and may also provide a promising venue for agronomists, physiologists, as well as molecular biologists. Full article
(This article belongs to the Special Issue Mechanisms of Drought, Temperature and Salinity Tolerance in Plants)
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18 pages, 753 KiB  
Review
Research Progress on the Roles of Cytokinin in Plant Response to Stress
by Yun Liu, Mingjing Zhang, Zhe Meng, Baoshan Wang and Min Chen
Int. J. Mol. Sci. 2020, 21(18), 6574; https://0-doi-org.brum.beds.ac.uk/10.3390/ijms21186574 - 08 Sep 2020
Cited by 46 | Viewed by 4926
Abstract
Cytokinins promote plant growth and development under normal plant growth conditions and also play an important role in plant resistance to stress. Understanding the working mechanisms of cytokinins under adverse conditions will help to make full use of cytokinins in agriculture to increase [...] Read more.
Cytokinins promote plant growth and development under normal plant growth conditions and also play an important role in plant resistance to stress. Understanding the working mechanisms of cytokinins under adverse conditions will help to make full use of cytokinins in agriculture to increase production and efficiency of land use. In this article, we review the progress that has been made in cytokinin research in plant response to stress and propose its future application prospects. Full article
(This article belongs to the Special Issue Mechanisms of Drought, Temperature and Salinity Tolerance in Plants)
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