title: Structural, functional, and evolutionary analysis of the unusually large stilbene synthase gene family in grapevine.
abstract: Stilbenes are a small family of phenylpropanoids produced in a number of unrelated plant species, including grapevine (Vitis vinifera). In addition to their participation in defense mechanisms in plants, stilbenes, such as resveratrol, display important pharmacological properties and are postulated to be involved in the health benefits associated with a moderate consumption of red wine. Stilbene synthases (STSs), which catalyze the biosynthesis of the stilbene backbone, seem to have evolved from chalcone synthases (CHSs) several times independently in stilbene-producing plants. STS genes usually form small families of two to five closely related paralogs. By contrast, the sequence of grapevine reference genome (cv PN40024) has revealed an unusually large STS gene family. Here, we combine molecular evolution and structural and functional analyses to investigate further the high number of STS genes in grapevine. Our reannotation of the STS and CHS gene families yielded 48 STS genes, including at least 32 potentially functional ones. Functional characterization of nine genes representing most of the STS gene family diversity clearly indicated that these genes do encode for proteins with STS activity. Evolutionary analysis of the STS gene family revealed that both STS and CHS evolution are dominated by purifying selection, with no evidence for strong selection for new functions among STS genes. However, we found a few sites under different selection pressures in CHS and STS sequences, whose potential functional consequences are discussed using a structural model of a typical STS from grapevine that we developed.
authors.affiliation: Unité Mixte de Recherche, Institut National de la Recherche Agronomique, 1131 Santé de la Vigne et Qualité du Vin, F-68021 Colmar, France.
authors.forename: Claire
authors.initials: C
authors.lastname: Parage
authors.forename: Raquel
authors.initials: R
authors.lastname: Tavares
authors.forename: Stéphane
authors.initials: S
authors.lastname: Réty
authors.forename: Raymonde
authors.initials: R
authors.lastname: Baltenweck-Guyot
authors.forename: Anne
authors.initials: A
authors.lastname: Poutaraud
authors.forename: Lauriane
authors.initials: L
authors.lastname: Renault
authors.forename: Dimitri
authors.initials: D
authors.lastname: Heintz
authors.forename: Raphaël
authors.initials: R
authors.lastname: Lugan
authors.forename: Gabriel A B
authors.initials: GA
authors.lastname: Marais
authors.forename: Sébastien
authors.initials: S
authors.lastname: Aubourg
authors.forename: Philippe
authors.initials: P
authors.lastname: Hugueney
mesh_terms: D000217:Acyltransferases / Q000737:chemistry* / Q000235:genetics* / Q000378:metabolism; D060054:Agrobacterium / Q000378:metabolism; D000596:Amino Acids / Q000235:genetics; D032461:Chromosomes, Plant / Q000235:genetics; D019143:Evolution, Molecular; D018506:Gene Expression Regulation, Plant; D017343:Genes, Plant / Q000235:genetics; D008958:Models, Molecular; D005810:Multigene Family / Q000235:genetics*; D010802:Phylogeny; D013267:Stilbenes / Q000737:chemistry / Q000378:metabolism; D013312:Stress, Physiological / Q000235:genetics; D014026:Nicotiana / Q000382:microbiology; D027843:Vitis / Q000201:enzymology* / Q000235:genetics*
chemical_list: D000596:Amino Acids; D013267:Stilbenes; D000217:Acyltransferases; C022674:stilbene synthase