Profiling of sugar transporter genes in grapevine coping with water deficit

AbstractThe profiling of grapevine (Vitis vinifera L.) genes under water deficit was specifically targeted to sugar transporters. Leaf water status was characterized by physiological parameters and soluble sugars content. The expression analysis provided evidence that VvHT1 hexose transporter gene was strongly down-regulated by the increased sugar content under mild water-deficit. The genes of monosaccharide transporter VvHT5, sucrose carrier VvSUC11, vacuolar invertase VvGIN2 and grape ASR (ABA, stress, ripening) were up-regulated under severe water stress. Their regulation in a drought-ABA signalling network and possible roles in complex interdependence between sugar subcellular partitioning and cell influx/efflux under Grapevine acclimation to dehydration are discussed

The <it>Vitis vinifera </it>sugar transporter gene family: phylogenetic overview and macroarray expression profiling

<p>Abstract</p> <p>Background</p> <p>In higher plants, sugars are not only nutrients but also important signal molecules. They are distributed through the plant <it>via </it>sugar transporters, which are involved not only in sugar long-distance transport <it>via </it>the loading and the unloading of the conducting complex, but also in sugar allocation into source and sink cells. The availability of the recently released grapevine genome sequence offers the opportunity to identify sucrose and monosaccharide transporter gene families in a woody species and to compare them with those of the herbaceous <it>Arabidopsis thaliana </it>using a phylogenetic analysis.</p> <p>Results</p> <p>In grapevine, one of the most economically important fruit crop in the world, it appeared that sucrose and monosaccharide transporter genes are present in 4 and 59 loci, respectively and that the monosaccharide transporter family can be divided into 7 subfamilies. Phylogenetic analysis of protein sequences has indicated that orthologs exist between <it>Vitis </it>and <it>Arabidospis</it>. A search for <it>cis</it>-regulatory elements in the promoter sequences of the most characterized transporter gene families (sucrose, hexoses and polyols transporters), has revealed that some of them might probably be regulated by sugars. To profile several genes simultaneously, we created a macroarray bearing cDNA fragments specific to 20 sugar transporter genes. This macroarray analysis has revealed that two hexose (<it>VvHT1</it>, <it>VvHT3</it>), one polyol (<it>VvPMT5</it>) and one sucrose (<it>VvSUC27</it>) transporter genes, are highly expressed in most vegetative organs. The expression of one hexose transporter (<it>VvHT2</it>) and two tonoplastic monosaccharide transporter (<it>VvTMT1</it>, <it>VvTMT2</it>) genes are regulated during berry development. Finally, three putative hexose transporter genes show a preferential organ specificity being highly expressed in seeds (<it>VvHT3</it>, <it>VvHT5</it>), in roots (<it>VvHT2</it>) or in mature leaves (<it>VvHT5</it>).</p> <p>Conclusions</p> <p>This study provides an exhaustive survey of sugar transporter genes in <it>Vitis vinifera </it>and revealed that sugar transporter gene families in this woody plant are strongly comparable to those of herbaceous species. Dedicated macroarrays have provided a <it>Vitis </it>sugar transporter genes expression profiling, which will likely contribute to understand their physiological functions in plant and berry development. The present results might also have a significant impact on our knowledge on plant sugar transporters.</p

Grape ASR Regulates Glucose Transport, Metabolism and Signaling

International audienceTo 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

Grape ASR Regulates Glucose Transport, Metabolism and Signaling.

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

Interaction of grape ASR proteins with a DREB transcription factor in the nucleus

AbstractASR proteins (abscissic acid, stress, ripening induced) are involved in plant responses to developmental and environmental signals but their biological functions remain to be elucidated. Grape ASR gene (VvMSA) encodes a new transcription factor regulating the expression of a glucose transporter. Here, we provide evidence for some polymorphism of grape ASRs and their identification as chromosomal non-histone proteins. By the yeast two-hybrid approach, a protein partner of VvMSA is isolated and characterized as an APETALA2 domain transcription factor. Interaction of the two proteins is further demonstrated by the BiFC approach and the exclusive nuclear localization of the heterodimer is visualized.Structured summaryMINT-6743067: VvMSA (uniprotkb:Q94G23) and VvDREB (uniprotkb:A6XA90) physically interact (MI:0218) by bimolecular fluorescence complementation (MI:0809)MINT-6743043: VvMSA (uniprotkb:Q94G23) physically interacts (MI:0218) with VvDREB (uniprotkb:A6XA90) by two hybrid (MI:0018

Erratum to "Links between lipid homeostasis, organelle morphodynamics and protein trafficking in eukaryotic and plant secretory pathways" [Plant Cell Rep. 30 (2011) 177-193]

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