title: A systems-oriented analysis of the grapevine R2R3-MYB transcription factor family uncovers new insights into the regulation of stilbene accumulation.
abstract: R2R3-MYB transcription factors (TFs) belong to a large and functionally diverse protein superfamily in plants. In this study, we explore the evolution and function of this family in grapevine (Vitis vinifera L.), a high-value fruit crop. We identified and manually curated 134 genes using RNA-Seq data, and named them systematically according to the Super-Nomenclature Committee. We identified novel genes, splicing variants and grapevine/woody-specific duplicated subgroups, suggesting possible neo- and sub-functionalization events. Regulatory network analysis ascribed biological functions to uncharacterized genes and validated those of known genes (e.g. secondary cell wall biogenesis and flavonoid biosynthesis). A comprehensive analysis of different MYB binding motifs in the promoters of co-expressed genes predicted grape R2R3-MYB binding preferences and supported evidence for putative downstream targets. Enrichment of cis-regulatory motifs for diverse TFs reinforced the notion of transcriptional coordination and interaction between MYBs and other regulators. Analysis of the network of Subgroup 2 showed that the resveratrol-related VviMYB14 and VviMYB15 share common co-expressed STILBENE SYNTHASE genes with the uncharacterized VviMYB13. These regulators have distinct expression patterns within organs and in response to biotic and abiotic stresses, suggesting a pivotal role of VviMYB13 in regulating stilbene accumulation in vegetative tissues and under biotic stress conditions.
authors.affiliation: Wine Research Centre, University of British Columbia, Vancouver, BC, Canada.
authors.forename: Darren Chern Jan
authors.initials: DCJ
authors.lastname: Wong
authors.affiliation: Department of Biology, ETH Zurich, 8092 Zurich, Switzerland.
authors.forename: Rudolf
authors.initials: R
authors.lastname: Schlechter
authors.affiliation: Department of Agronomy, Food, Natural Resources, Animals, and Environment, University of Padova, 35020 Legnaro, Padova, Italy.
authors.forename: Alessandro
authors.initials: A
authors.lastname: Vannozzi
authors.affiliation: Centre for Organismal Studies Heidelberg, University of Heidelberg, 69120 Heidelberg, Germany.
authors.forename: Janine
authors.initials: J
authors.lastname: Höll
authors.affiliation: Department of Agronomy, Food, Natural Resources, Animals, and Environment, University of Padova, 35020 Legnaro, Padova, Italy.
authors.forename: Ibrahim
authors.initials: I
authors.lastname: Hmmam
authors.affiliation: Dienstleistungszentrum Laendlicher Raum Rheinpfalz, Breitenweg 71, Viticulture and Enology Group, 67435 Neustadt/W, Germany.|Fachhochschule Bingen, Berlinstr. 109, 55411 Bingen am Rhein, Germany.
authors.forename: Jochen
authors.initials: J
authors.lastname: Bogs
authors.affiliation: Department of Biotechnology, University of Verona, 15 - 37134 Verona, Italy.
authors.forename: Giovanni Battista
authors.initials: GB
authors.lastname: Tornielli
authors.affiliation: Wine Research Centre, University of British Columbia, Vancouver, BC, Canada.
authors.forename: Simone Diego
authors.initials: SD
authors.lastname: Castellarin
authors.affiliation: Center for Research in Agricultural Genomics CSIC-IRTA-UAB-UB, Barcelona 08193, Spain.
authors.forename: José Tomás
authors.initials: JT
authors.lastname: Matus
keywords: cell wall; radiation; ripening; stress; wine