Editorial

4 pages, 208 KiB

Open AccessEditorial

Special Issue “Sugar Transport, Metabolism and Signaling in Plants”

by Soulaiman Sakr

Int. J. Mol. Sci. 2023, 24(6), 5655; https://0-doi-org.brum.beds.ac.uk/10.3390/ijms24065655 - 16 Mar 2023

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Sucrose and its derivative hexoses are key metabolites of the plant metabolism, structural units of cell walls and stored reserves (e [...] Full article

(This article belongs to the Special Issue Sugar Transport, Metabolism and Signalling in Plant)

Research

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21 pages, 9012 KiB

Open AccessArticle

Combined Metabolome and Transcriptome Analysis Elucidates Sugar Accumulation in Wucai (Brassica campestris L.)

by Chenggang Wang, Jiajie Zhou, Shengnan Zhang, Xun Gao, Yitao Yang, Jinfeng Hou, Guohu Chen, Xiaoyan Tang, Jianqiang Wu and Lingyun Yuan

Int. J. Mol. Sci. 2023, 24(5), 4816; https://0-doi-org.brum.beds.ac.uk/10.3390/ijms24054816 - 02 Mar 2023

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Abstract

Wucai (Brassica campestris L.) is a leafy vegetable that originated in China, its soluble sugars accumulate significantly to improve taste quality during maturation, and it is widely accepted by consumers. In this study, we investigated the soluble sugar content at different developmental [...] Read more.

Wucai (Brassica campestris L.) is a leafy vegetable that originated in China, its soluble sugars accumulate significantly to improve taste quality during maturation, and it is widely accepted by consumers. In this study, we investigated the soluble sugar content at different developmental stages. Two periods including 34 days after planting (DAP) and 46 DAP, which represent the period prior to and after sugar accumulation, respectively, were selected for metabolomic and transcriptomic profiling. Differentially accumulated metabolites (DAMs) were mainly enriched in the pentose phosphate pathway, galactose metabolism, glycolysis/gluconeogenesis, starch and sucrose metabolism, and fructose and mannose metabolism. By orthogonal projection to latent structures-discriminant s-plot (OPLS-DA S-plot) and MetaboAnalyst analyses, D-galactose and β-D-glucose were identified as the major components of sugar accumulation in wucai. Combined with the transcriptome, the pathway of sugar accumulation and the interact network between 26 DEGs and the two sugars were mapped. CWINV4, CEL1, BGLU16, and BraA03g023380.3C had positive correlations with the accumulation of sugar accumulation in wucai. The lower expression of BraA06g003260.3C, BraA08g002960.3C, BraA05g019040.3C, and BraA05g027230.3C promoted sugar accumulation during the ripening of wucai. These findings provide insights into the mechanisms underlying sugar accumulation during commodity maturity, providing a basis for the breeding of sugar-rich wucai cultivars. Full article

(This article belongs to the Special Issue Sugar Transport, Metabolism and Signalling in Plant)

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14 pages, 3645 KiB

Open AccessArticle

Characterization of the SWEET Gene Family in Longan (Dimocarpus longan) and the Role of DlSWEET1 in Cold Tolerance

by Ting Fang, Ya Rao, Mengzhen Wang, Yun Li, Yujun Liu, Pengpeng Xiong and Lihui Zeng

Int. J. Mol. Sci. 2022, 23(16), 8914; https://0-doi-org.brum.beds.ac.uk/10.3390/ijms23168914 - 10 Aug 2022

Cited by 9 | Viewed by 1770

Abstract

Sugars will eventually be exported transporters (SWEET), a group of relatively novel sugar transporters, that play important roles in phloem loading, seed and fruit development, pollen development, and stress response in plants. Longan (Dimocarpus longan), a subtropic fruit tree with high [...] Read more.

Sugars will eventually be exported transporters (SWEET), a group of relatively novel sugar transporters, that play important roles in phloem loading, seed and fruit development, pollen development, and stress response in plants. Longan (Dimocarpus longan), a subtropic fruit tree with high economic value, is sensitive to cold. However, whether the SWEET gene family plays a role in conferring cold tolerance upon longan remains unknown. Here, a total of 20 longan SWEET (DlSWEET) genes were identified, and their phylogenetic relationships, gene structures, cis-acting elements, and tissue-specific expression patterns were systematically analyzed. This family is divided into four clades. Gene structures and motifs analyses indicated that the majority of DlSWEETs in each clade shared similar exon–intron organization and conserved motifs. Tissue-specific gene expression suggested diverse possible functions for DlSWEET genes. Cis-elements analysis and quantitative real-time PCR (qRT-PCR) analysis revealed that DlSWEET1 responded to cold stress. Notably, the overexpression of DlSWEET1 improved cold tolerance in transgenic Arabidopsis, suggesting that DlSWEET1 might play a positive role in D. longan’s responses to cold stress. Together, these results contribute to a better understanding of SWEET genes, which could serve as a foundation for the further functional identification of these genes. Full article

(This article belongs to the Special Issue Sugar Transport, Metabolism and Signalling in Plant)

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30 pages, 6105 KiB

Open AccessArticle

Grape ASR Regulates Glucose Transport, Metabolism and Signaling

by Jonathan Parrilla, Anna Medici, Cécile Gaillard, Jérémy Verbeke, Yves Gibon, Dominique Rolin, Maryse Laloi, Ruth R. Finkelstein and Rossitza Atanassova

Int. J. Mol. Sci. 2022, 23(11), 6194; https://0-doi-org.brum.beds.ac.uk/10.3390/ijms23116194 - 31 May 2022

Cited by 4 | Viewed by 1691

Abstract

To decipher the mediator role of the grape Abscisic acid, Stress, Ripening (ASR) protein, VvMSA, in the pathways of glucose signaling through the regulation of its target, the promoter of hexose transporter VvHT1, we overexpressed and repressed VvMSA in embryogenic and non-embryogenic grapevine [...] Read more.

To decipher the mediator role of the grape Abscisic acid, Stress, Ripening (ASR) protein, VvMSA, in the pathways of glucose signaling through the regulation of its target, the promoter of hexose transporter VvHT1, we overexpressed and repressed VvMSA in embryogenic and non-embryogenic grapevine cells. The embryogenic cells with organized cell proliferation were chosen as an appropriate model for high sensitivity to the glucose signal, due to their very low intracellular glucose content and low glycolysis flux. In contrast, the non-embryogenic cells displaying anarchic cell proliferation, supported by high glycolysis flux and a partial switch to fermentation, appeared particularly sensitive to inhibitors of glucose metabolism. By using different glucose analogs to discriminate between distinct pathways of glucose signal transduction, we revealed VvMSA positioning as a transcriptional regulator of the glucose transporter gene VvHT1 in glycolysis-dependent glucose signaling. The effects of both the overexpression and repression of VvMSA on glucose transport and metabolism via glycolysis were analyzed, and the results demonstrated its role as a mediator in the interplay of glucose metabolism, transport and signaling. The overexpression of VvMSA in the Arabidopsis mutant abi8 provided evidence for its partial functional complementation by improving glucose absorption activity. Full article

(This article belongs to the Special Issue Sugar Transport, Metabolism and Signalling in Plant)

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15 pages, 1588 KiB

Open AccessArticle

Sink Strength Promoting Remobilization of Non-Structural Carbohydrates by Activating Sugar Signaling in Rice Stem during Grain Filling

by Zhengrong Jiang, Qiuli Chen, Lin Chen, Dun Liu, Hongyi Yang, Congshan Xu, Jinzhi Hong, Jiaqi Li, Yanfeng Ding, Soulaiman Sakr, Zhenghui Liu, Yu Jiang and Ganghua Li

Int. J. Mol. Sci. 2022, 23(9), 4864; https://0-doi-org.brum.beds.ac.uk/10.3390/ijms23094864 - 27 Apr 2022

Cited by 5 | Viewed by 2064

Abstract

The remobilization of non-structural carbohydrates (NSCs) in the stem is essential for rice grain filling so as to improve grain yield. We conducted a two-year field experiment to deeply investigate their relationship. Two large-panicle rice varieties with similar spikelet size, CJ03 and W1844, [...] Read more.

The remobilization of non-structural carbohydrates (NSCs) in the stem is essential for rice grain filling so as to improve grain yield. We conducted a two-year field experiment to deeply investigate their relationship. Two large-panicle rice varieties with similar spikelet size, CJ03 and W1844, were used to conduct two treatments (removing-spikelet group and control group). Compared to CJ03, W1844 had higher 1000-grain weight, especially for the grain growth of inferior spikelets (IS) after removing the spikelet. These results were mainly ascribed to the stronger sink strength of W1844 than that of CJ03 contrasting in the same group. The remobilization efficiency of NSC in the stem decreased significantly after removing the spikelet for both CJ03 and W1844, and the level of sugar signaling in the T6P-SnRK1 pathway was also significantly changed. However, W1844 outperformed CJ03 in terms of the efficiency of carbon reserve remobilization under the same treatments. More precisely, there was a significant difference during the early grain-filling stage in terms of the conversion of sucrose and starch. Interestingly, the sugar signaling of the T6P and SnRK1 pathways also represented an obvious change. Hence, sugar signaling may be promoted by sink strength to remobilize the NSCs of the rice stem during grain filling to further advance crop yield. Full article

(This article belongs to the Special Issue Sugar Transport, Metabolism and Signalling in Plant)

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15 pages, 5942 KiB

Open AccessArticle

Characterization of Stem Nodes Associated with Carbon Partitioning in Maize in Response to Nitrogen Availability

by Yujing Zhao, Peng Ning, Xiaojie Feng, Hanshuo Ren, Mingtang Cui and Lu Yang

Int. J. Mol. Sci. 2022, 23(8), 4389; https://doi.org/10.3390/ijms23084389 - 15 Apr 2022

Cited by 3 | Viewed by 2089

Abstract

Stem node has been found to be a hub for controlling mineral nutrient distribution in gramineous plants. However, the characteristics of stem nodes associated with whole-plant carbon partitioning in maize (Zea mays L.) and their responses to nitrogen (N) availability remains elusive. [...] Read more.

Stem node has been found to be a hub for controlling mineral nutrient distribution in gramineous plants. However, the characteristics of stem nodes associated with whole-plant carbon partitioning in maize (Zea mays L.) and their responses to nitrogen (N) availability remains elusive. Maize plants were grown in greenhouse under low to high N supply. Plant growth, sugar accumulation, and sugar transporters in nodes and leaves, as well as the anatomical structure of nodes, were investigated at vegetative phase. When compared to N-sufficient plants, low-N availability stunted growth and resulted in 49–64% less sugars in leaves, which was attributed to low photosynthesis or the accelerated carbon export, as evidenced by more ¹³C detected further below leaf tips. Invariably higher sugar concentrations were found in the stem nodes, rather than in the leaves across N treatments, indicating a crucial role of nodes in facilitating whole-plant carbon partitioning. More and smaller vascular bundles and phloem were observed in stem nodes of N-deficient plants, while higher sugar levels were found in the bottom nodes than in the upper ones. Low-N availability upregulated the gene expressions of sugar transporters, which putatively function in nodes such as ZmSWEETs and ZmSUTs at the bottom stem, but suppressed them in the upper ones, showing a developmental impact on node function. Further, greater activity of sugar transporters in the bottom nodes was associated with less sugars in leaves. Overall, these results highlighted that stem nodes may play an important role in facilitating long-distance sugar transport in maize. Full article

(This article belongs to the Special Issue Sugar Transport, Metabolism and Signalling in Plant)

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17 pages, 4659 KiB

Open AccessArticle

CsSWEET2, a Hexose Transporter from Cucumber (Cucumis sativus L.), Affects Sugar Metabolism and Improves Cold Tolerance in Arabidopsis

by Liping Hu, Feng Zhang, Shuhui Song, Xiaolu Yu, Yi Ren, Xuezhi Zhao, Huan Liu, Guangmin Liu, Yaqin Wang and Hongju He

Int. J. Mol. Sci. 2022, 23(7), 3886; https://0-doi-org.brum.beds.ac.uk/10.3390/ijms23073886 - 31 Mar 2022

Cited by 14 | Viewed by 2112

Abstract

Sugars, which are critical osmotic compounds and signalling molecules in plants, and Sugars Will Eventually be Exported Transporters (SWEETs), which constitute a novel family of sugar transporters, play central roles in plant responses to multiple abiotic stresses. In the present study, a member [...] Read more.

Sugars, which are critical osmotic compounds and signalling molecules in plants, and Sugars Will Eventually be Exported Transporters (SWEETs), which constitute a novel family of sugar transporters, play central roles in plant responses to multiple abiotic stresses. In the present study, a member of the SWEET gene family from cucumber (Cucumis sativus L.), CsSWEET2, was identified and characterized. Histochemical analysis of β-glucuronidase expression in transgenic Arabidopsis plants showed that CsSWEET2 is highly expressed in the leaves; subcellular localization indicated that CsSWEET2 proteins are localized in the plasma membrane and endoplasmic reticulum. Heterologous expression assays in yeast demonstrated that CsSWEET2 encodes an energy-independent hexose/H⁺ uniporter that can complement both glucose and fructose transport deficiencies. Compared with wild-type Arabidopsis plants, transgenic Arabidopsis plants overexpressing CsSWEET2 had much lower relative electrolyte leakage levels and were much more resistant to cold stress. Sugar content analysis showed that glucose and fructose levels in the transgenic Arabidopsis plants were significantly higher than those in the wild-type plants. Taken together, our results suggest that, by mediating sugar metabolism and compartmentation, CsSWEET2 plays a vital role in improving plant cold tolerance. Full article

(This article belongs to the Special Issue Sugar Transport, Metabolism and Signalling in Plant)

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Review

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16 pages, 793 KiB

Open AccessReview

Glucose-6-Phosphate Dehydrogenases: The Hidden Players of Plant Physiology

by Zhengrong Jiang, Ming Wang, Michael Nicolas, Laurent Ogé, Maria-Dolores Pérez-Garcia, Laurent Crespel, Ganghua Li, Yanfeng Ding, José Le Gourrierec, Philippe Grappin and Soulaiman Sakr

Int. J. Mol. Sci. 2022, 23(24), 16128; https://0-doi-org.brum.beds.ac.uk/10.3390/ijms232416128 - 17 Dec 2022

Cited by 9 | Viewed by 3121

Abstract

Glucose-6-phosphate dehydrogenase (G6PDH) catalyzes a metabolic hub between glycolysis and the pentose phosphate pathway (PPP), which is the oxidation of glucose-6-phosphate (G6P) to 6-phosphogluconolactone concomitantly with the production of nicotinamide adenine dinucleotide phosphate (NADPH), a reducing power. It is considered to be the [...] Read more.

Glucose-6-phosphate dehydrogenase (G6PDH) catalyzes a metabolic hub between glycolysis and the pentose phosphate pathway (PPP), which is the oxidation of glucose-6-phosphate (G6P) to 6-phosphogluconolactone concomitantly with the production of nicotinamide adenine dinucleotide phosphate (NADPH), a reducing power. It is considered to be the rate-limiting step that governs carbon flow through the oxidative pentose phosphate pathway (OPPP). The OPPP is the main supplier of reductant (NADPH) for several “reducing” biosynthetic reactions. Although it is involved in multiple physiological processes, current knowledge on its exact role and regulation is still piecemeal. The present review provides a concise and comprehensive picture of the diversity of plant G6PDHs and their role in seed germination, nitrogen assimilation, plant branching, and plant response to abiotic stress. This work will help define future research directions to improve our knowledge of G6PDHs in plant physiology and to integrate this hidden player in plant performance. Full article

(This article belongs to the Special Issue Sugar Transport, Metabolism and Signalling in Plant)

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