Structural, Functional, and Evolutionary Analysis of the Unusually Large Stilbene Synthase Gene Family in Grapevine  

Abstract

de Ciência, P-2780-156 Oeiras, Portugal (R.T., G.A.B.M.)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.

Regulation of stilbene biosynthesis in plants

“…The available literature data demonstrate that STS genes in sorghum, spruce, pine, peanut, and mulberry form small gene families composed of 1-10 members (Preisig-Müller et al 1999;Yu et al 2005;Paterson et al 2009;Zhu et al 2014;Warren et al 2015;Li et al 2016), while STS gene family in grapevine consists of 48 STS genes with at least 32 potentially functional ones as revealed by the genomewide analysis of the grapevine genome (Vannozzi et al 2012;Parage et al 2012). Functional analysis of nine STS genes representing most diversity of the STS gene family in grapevine performed by Parage et al (2012) revealed that the genes encode proteins possessing STS activity.…”

“…Functional analysis of nine STS genes representing most diversity of the STS gene family in grapevine performed by Parage et al (2012) revealed that the genes encode proteins possessing STS activity. It is possible that different STS genes encode enzymes with unequal activities or specificity.…”

Skin Browning and Expression of PPO, STS, and CHS Genes in the Grape Berries of ‘Shine Muscat’

“…This STS activity has been detected in the primary and secondary cell walls after UV treatment, results that are consistent with a defense function (Pan et al, 2009). In grapevine, CHS is encoded by a small gene family consisting of three homologous genes (Parage et al, 2012;Vannozzi et al, 2012), whereas STS is encoded by a large gene family with 48 homologous genes in the grape genome (Parage et al, 2012;Vannozzi et al, 2012;Velasco et al, 2007).…”

“…For stilbene synthase (STS) and chalcone synthase (CHS) genes, the detailed explanations are in recent reports (Goto-Yamamoto et al, 2002;Gutha et al, 2010;Parage et al, 2012;Vannozzi et al, 2012). The 48 predicted STS genes in the grape genome have been divided into three groups based on phylogenic analysis (VvSTS types A, B, and C in this study) (Parage et al, 2012;Vannozzi et al, 2012).…”

“…The 48 predicted STS genes in the grape genome have been divided into three groups based on phylogenic analysis (VvSTS types A, B, and C in this study) (Parage et al, 2012;Vannozzi et al, 2012). According to Vannozzi et al (2012), five of the predicted genes are type A, 22 are type B, and 13 are type C. The remaining eight genes do not have complete ORFs.…”