The MYB5-driven MBW complex recruits a WRKY factor to enhance the expression of targets involved in vacuolar hyper-acidification and trafficking in grapevine
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ABSTRACT: The accumulation of secondary metabolites and the regulation of tissue acidity contribute to important traits like color, astringency and acidity of grape berry which are essential to the value of the final product, the wine. Moreover, they influence the plant performance in response to the environment and to parasites and herbivores. In several plant species highly conserved WD-MYB-bHLH-WRKY (WMBW) transcriptional complexes determine color and acidity in epidermal cells. Here we investigated the function in grapevine (Vitis vinifera L.) of WMBW complexes involving two MYBs (VvMYB5a and VvMYB5b) and the WRKY-type transcription factor VvWRKY26. Using transgenic grapevine plants we show that these complexes affect different aspects of morphology, plant development, pH regulation, and pigment accumulation. Transcriptomic analysis identified a core set of putative target genes controlled by VvMYB5a, VvMYB5b and VvWRKY26 in different tissues. Our data indicate that VvWRKY26 enhances the expression of selected target genes induced by VvMYB5a/b. Among these target genes are enzymes of the biosynthesis of flavonoids, genes involved in cell-type identity and the P-type ATPases VvPH5 and VvPH1. In addition, VvWRKY26 is recruited specifically by VvMYB5a, reflecting the functional diversification of VvMYB5a and VvMYB5b. The expression of WBMW complexes in vegetative organs, such as leaves, indicates a possible function of vacuolar hyper-acidification in repulsion of parasites/herbivores and/or in developmental processes as shown by defects in transgenic grape plants where the WMBW complex is inactivated.
ORGANISM(S): Vitis vinifera
PROVIDER: GSE111468 | GEO | 2019/05/22
REPOSITORIES: GEO
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