scholarly journals Involvement of SUT1 and SUT2 Sugar Transporters in the Impairment of Sugar Transport and Changes in Phloem Exudate Contents in Phytoplasma-Infected Plants

2021 ◽  
Vol 22 (2) ◽  
pp. 745
Author(s):  
Federica De Marco ◽  
Brigitte Batailler ◽  
Michael R. Thorpe ◽  
Frédérique Razan ◽  
Rozenn Le Hir ◽  
...  
Keyword(s):  
Metabolite Profiling ◽  
Sugar Transport ◽  
Starch Accumulation ◽  
Primary Metabolism ◽  
Phloem Exudate ◽  
Phloem Sap ◽  
Sugar Transporters ◽  
Abnormal Growth ◽  
Sucrose Transporters

Phytoplasmas inhabit phloem sieve elements and cause abnormal growth and altered sugar partitioning. However, how they interact with phloem functions is not clearly known. The phloem responses were investigated in tomatoes infected by “Candidatus Phytoplasma solani” at the beginning of the symptomatic stage, the first symptoms appearing in the newly emerged leaf at the stem apex. Antisense lines impaired in the phloem sucrose transporters SUT1 and SUT2 were included. In symptomatic sink leaves, leaf curling was associated with higher starch accumulation and the expression of defense genes. The analysis of leaf midribs of symptomatic leaves indicated that transcript levels for genes acting in the glycolysis and peroxisome metabolism differed from these in noninfected plants. The phytoplasma also multiplied in the three lower source leaves, even if it was not associated with the symptoms. In these leaves, the rate of phloem sucrose exudation was lower for infected plants. Metabolite profiling of phloem sap-enriched exudates revealed that glycolate and aspartate levels were affected by the infection. Their levels were also affected in the noninfected SUT1- and SUT2-antisense lines. The findings suggest the role of sugar transporters in the responses to infection and describe the consequences of impaired sugar transport on the primary metabolism.

scholarly journals Role of the SUT1 and SUT2 sugar transporters during stolbur phytoplasma infection in tomato

2020 ◽  
Author(s):  
Federica De Marco ◽  
Brigitte Batailler ◽  
Michael R. Thorpe ◽  
Frédérique Razan ◽  
Rozenn Le Hir ◽  
...  
Keyword(s):  
Redox Homeostasis ◽  
Sugar Transport ◽  
Transcriptional Analysis ◽  
Starch Accumulation ◽  
Metabolic Switch ◽  
Sieve Elements ◽  
Sugar Transporters ◽  
Abnormal Growth ◽  
Sucrose Transporters ◽  
Phytoplasma Infection

SummaryPhytoplasmas inhabit phloem sieve elements and cause abnormal growth and altered sugar partitioning. But how they interact with phloem functions is not clearly known. The phloem responses were investigated in tomato infected by ‘Candidatus Phytoplasma solani’, at the beginning of the symptomatic stage of infection, both in symptomatic and asymptomatic leaves, the first symptoms appearing in the sink top leaf at the stem apex. Antisense lines impaired in the phloem sucrose transporters SUT1 and SUT2 were included. The infection in source leaves was not associated with symptoms. In the symptomatic, sink leaf, yellowing and leaf curling was associated with higher starch accumulation and expression of defense genes. The transcriptional analysis of symptomatic leaf midribs indicated that transcript levels for genes acting in the glycolysis and peroxisome metabolism in infected plants differed from these in non-infected plants. Phytoplasma multiplied actively in at least three additional lower leaves although they were symptomless, with no sign of activation of defense markers, although the rate of exudation of sucrose from these symptomless, source leaves was lower for infected plants. A few metabolites in phloem-enriched exudate were affected by the infection, such as glycolate and aspartate, and some of them were also affected in the control SUT1- and SUT2- antisense lines, in which sucrose retrieval or release in the sieve elements are impaired. A metabolic switch could explain the delivery of more glycolate into the sieve elements of infected plants. The findings suggest a link between sugar transport and redox homeostasis.One sentence summaryAn impairment of sucrose retrieval and release in the sieve elements occurs during phytoplasma infection, associated with changes in sugar and peroxisome metabolism

scholarly journals Plasma membrane-localized SlSWEET7a and SlSWEET14 regulate sugar transport and storage in tomato fruits

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Xinsheng Zhang ◽  
Chaoyang Feng ◽  
Manning Wang ◽  
Tianlai Li ◽  
Xin Liu ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Sugar Content ◽  
Sugar Transport ◽  
Invertase Activity ◽  
Vascular Bundles ◽  
Tomato Fruits ◽  
Sugar Transporters ◽  
Potential Strategy ◽  
And Storage

AbstractSugars, especially glucose and fructose, contribute to the taste and quality of tomato fruits. These compounds are translocated from the leaves to the fruits and then unloaded into the fruits by various sugar transporters at the plasma membrane. SWEETs, are sugar transporters that regulate sugar efflux independently of energy or pH. To date, the role of SWEETs in tomato has received very little attention. In this study, we performed functional analysis of SlSWEET7a and SlSWEET14 to gain insight into the regulation of sugar transport and storage in tomato fruits. SlSWEET7a and SlSWEET14 were mainly expressed in peduncles, vascular bundles, and seeds. Both SlSWEET7a and SlSWEET14 are plasma membrane-localized proteins that transport fructose, glucose, and sucrose. Apart from the resulting increase in mature fruit sugar content, silencing SlSWEET7a or SlSWEET14 resulted in taller plants and larger fruits (in SlSWEET7a-silenced lines). We also found that invertase activity and gene expression of some SlSWEET members increased, which was consistent with the increased availability of sucrose and hexose in the fruits. Overall, our results demonstrate that suppressing SlSWEET7a and SlSWEET14 could be a potential strategy for enhancing the sugar content of tomato fruits.

scholarly journals Overexpression of Melon Tonoplast Sugar Transporter CmTST1 Improved Root Growth under High Sugar Content

2020 ◽  
Vol 21 (10) ◽  
pp. 3524
Author(s):  
Baiyi Lu ◽  
Suying Wen ◽  
Peilu Zhu ◽  
Haishun Cao ◽  
Yixuan Zhou ◽  
...  
Keyword(s):  
Root Growth ◽  
Intracellular Transport ◽  
Sugar Content ◽  
Ectopic Expression ◽  
Sugar Transport ◽  
Sugar Transporters ◽  
Source To Sink ◽  
High Sugar Content ◽  
High Level

Sugar allocation is based on the source-to-sink and intracellular transport between different organelles, and sugar transporters are usually involved in these processes. Tonoplast sugar transporters (TST) are responsible for transporting sugar into vacuoles; however, the role of TSTs in root growth and the response to abiotic stress is poorly studied. Here, RNA analysis and promoter-β-glucuronidase staining revealed that a melon TST1 gene (CmTST1) is highly expressed in the roots. The sugar feeding experiment results showed that the expression of CmTST1 in the roots was induced by a relatively high level of sucrose (6%), glucose (3%), and fructose (3%). The ectopic overexpression of CmTST1 in Arabidopsis improved the root and shoot growth of seedlings under high exogenous sugar stress. Furthermore, the ectopic expression of CmTST1 promoted the expression of plasma membrane-located sugar transporters. We proposed that CmTST1 plays a key role in importing sugar transport into the vacuoles of roots in response to metabolic demands to maintain cytosolic sugar homeostasis.

scholarly journals VvSWEET10 Mediates Sugar Accumulation in Grapes

Genes ◽  
2019 ◽  
Vol 10 (4) ◽  
pp. 255 ◽  
Author(s):  
Zhan Zhang ◽  
Luming Zou ◽  
Chong Ren ◽  
Fengrui Ren ◽  
Yi Wang ◽  
...  
Keyword(s):  
Sugar Content ◽  
Sugar Transport ◽  
Grape Berry ◽  
Critical Event ◽  
Sugar Accumulation ◽  
Sugar Transporters ◽  
Market Values ◽  
Berry Quality ◽  
Sugar Levels

Sugar accumulation is a critical event during grape berry ripening that determines the grape market values. Berry cells are highly dependent on sugar transporters to mediate cross-membrane transport. However, the role of sugar transporters in improving sugar accumulation in berries is not well established in grapes. Herein we report that a Sugars Will Eventually be Exported Transporter (SWEET), that is, VvSWEET10, was strongly expressed at the onset of ripening (véraison) and can improve grape sugar content. VvSWEET10 encodes a plasma membrane-localized transporter, and the heterologous expression of VvSWEET10 indicates that VvSWEET10 is a hexose-affinity transporter and has a broad spectrum of sugar transport functions. VvSWEET10 overexpression in grapevine calli and tomatoes increased the glucose, fructose, and total sugar levels significantly. The RNA sequencing results of grapevine transgenic calli showed that many sugar transporter genes and invertase genes were upregulated and suggest that VvSWEET10 may mediate sugar accumulation. These findings elucidated the role of VvSWEET10 in sugar accumulation and will be beneficial for the improvement of grape berry quality in the future.

scholarly journals Role of photosynthesis and analysis of key enzymes involved in primary metabolism throughout the lifespan of the tobacco flower

2010 ◽  
Vol 61 (13) ◽  
pp. 3675-3688 ◽  
Author(s):  
Gabriela Leticia Müller ◽  
María Fabiana Drincovich ◽  
Carlos Santiago Andreo ◽  
María Valeria Lara
Keyword(s):  
Primary Metabolism ◽  
Key Enzymes

scholarly journals Melatonin and Carbohydrate Metabolism in Plant Cells

Plants ◽  
2021 ◽  
Vol 10 (9) ◽  
pp. 1917
Author(s):  
Marino B. Arnao ◽  
Josefa Hernández-Ruiz ◽  
Antonio Cano ◽  
Russel J. Reiter
Keyword(s):  
Crop Improvement ◽  
Plant Cells ◽  
Primary Metabolism ◽  
Degradation Pathways ◽  
Biotic And Abiotic Stress ◽  
Relevant Role ◽  
Tolerance Response ◽  
Simple Carbohydrates ◽  
Living Organisms

Melatonin, a multifunctional molecule that is present in all living organisms studied, is synthesized in plant cells in several intercellular organelles including in the chloroplasts and in mitochondria. In plants, melatonin has a relevant role as a modulatory agent which improves their tolerance response to biotic and abiotic stress. The role of melatonin in stress conditions on the primary metabolism of plant carbohydrates is reviewed in the present work. Thus, the modulatory actions of melatonin on the various biosynthetic and degradation pathways involving simple carbohydrates (mono- and disaccharides), polymers (starch), and derivatives (polyalcohols) in plants are evaluated. The possible applications of the use of melatonin in crop improvement and postharvest products are examined.

scholarly journals What is the role of sporadic phloem sap nitrate?

2021 ◽  
Author(s):  
Jing Cui ◽  
Andreas D. Peuke ◽  
Anis Limami ◽  
Guillaume Tcherkez
Keyword(s):  
Nutrient Cycling ◽  
Physical Properties ◽  
Plant Development ◽  
Nutrient Transport ◽  
Substantial Evidence ◽  
Phloem Sap ◽  
Essential Component

Since the first description of phloem sap composition nearly 60 years ago, it is generally assumed that phloem sap does not contain nitrate and that there is little or no backflow of nitrate from shoots to roots. While it is true that nitrate can occasionally be absent from phloem sap, there is now substantial evidence that phloem can carry nitrate and furthermore, transporters involved in nitrate redistribution to shoot sink organs and roots have been found. This raises the question of why nitrate may or may not be present in phloem sap, why its concentration is generally kept low, and whether plant shoot-root nutrient cycling also involves nitrate. We propose here that phloem sap nitrate is not only an essential component of plant nutritional signaling but also contributes to physical properties of phloem sap and as such, its concentration is controlled to ensure proper coordination of plant development and nutrient transport.

When SWEETs Turn Tweens: Updates and Perspectives

2021 ◽  
Vol 73 (1) ◽  
Author(s):  
Xueyi Xue ◽  
Jiang Wang ◽  
Diwakar Shukla ◽  
Lily S. Cheung ◽  
Li-Qing Chen
Keyword(s):  
Crop Yields ◽  
Sugar Transport ◽  
Basic Research ◽  
Biochemical Properties ◽  
Annual Review ◽  
Publication Date ◽  
Sugar Transporters ◽  
Evolutionary Origins ◽  
Plant Level ◽  
Dynamics Simulations

Sugar translocation between cells and between subcellular compartments in plants requires either plasmodesmata or a diverse array of sugar transporters. Interactions between plants and associated microorganisms also depend on sugar transporters. The sugars will eventually be exported transporter (SWEET) family is made up of conserved and essential transporters involved in many critical biological processes. The functional significance and small size of these proteins have motivated crystallographers to successfully capture several structures of SWEETs and their bacterial homologs in different conformations. These studies together with molecular dynamics simulations have provided unprecedented insights into sugar transport mechanisms in general and into substrate recognition of glucose and sucrose in particular. This review summarizes our current understanding of the SWEET family, from the atomic to the whole-plant level. We cover methods used for their characterization, theories about their evolutionary origins, biochemical properties, physiological functions, and regulation. We also include perspectives on the future work needed to translate basic research into higher crop yields. Expected final online publication date for the Annual Review of Plant Biology, Volume 73 is May 2022. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.

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