Transcriptional analysis of late ripening stages of grapevine berry.

Romain Fouquet,Sabine Guillaumie,Paul K Boss,Christian Kappel,Nancy Terrier,Céline Camps,Serge Delrot,Dominique Moncomble,Christopher Davies,Jake D Dunlevy

doi:10.1186/1471-2229-11-165

Abstract

BackgroundThe composition of grapevine berry at harvest is a major determinant of wine quality. Optimal oenological maturity of berries is characterized by a high sugar/acidity ratio, high anthocyanin content in the skin, and low astringency. However, harvest time is still mostly determined empirically, based on crude biochemical composition and berry tasting. In this context, it is interesting to identify genes that are expressed/repressed specifically at the late stages of ripening and which may be used as indicators of maturity.ResultsWhole bunches and berries sorted by density were collected in vineyard on Chardonnay (white cultivar) grapevines for two consecutive years at three stages of ripening (7-days before harvest (TH-7), harvest (TH), and 10-days after harvest (TH+10)). Microvinification and sensory analysis indicate that the quality of the wines made from the whole bunches collected at TH-7, TH and TH+10 differed, TH providing the highest quality wines.In parallel, gene expression was studied with Qiagen/Operon microarrays using two types of samples, i.e. whole bunches and berries sorted by density. Only 12 genes were consistently up- or down-regulated in whole bunches and density sorted berries for the two years studied in Chardonnay. 52 genes were differentially expressed between the TH-7 and TH samples. In order to determine whether these genes followed a similar pattern of expression during the late stages of berry ripening in a red cultivar, nine genes were selected for RT-PCR analysis with Cabernet Sauvignon grown under two different temperature regimes affecting the precocity of ripening. The expression profiles and their relationship to ripening were confirmed in Cabernet Sauvignon for seven genes, encoding a carotenoid cleavage dioxygenase, a galactinol synthase, a late embryogenesis abundant protein, a dirigent-like protein, a histidine kinase receptor, a valencene synthase and a putative S-adenosyl-L-methionine:salicylic acid carboxyl methyltransferase.ConclusionsThis set of up- and down-regulated genes characterize the late stages of berry ripening in the two cultivars studied, and are indirectly linked to wine quality. They might be used directly or indirectly to design immunological, biochemical or molecular tools aimed at the determination of optimal ripening in these cultivars.

Highlights

The composition of grapevine berry at harvest is a major determinant of wine quality
The present study describes a detailed analysis of gene expression in Chardonnay berries sampled at three different stages during late ripening
Chardonnay berry samples were harvested over the course of berry ripening from the Comité Interprofessionel du Vin de Champagne (CIVC) vineyard in Champagne (France) during fall 2005 and 2006

Summary

Introduction

The composition of grapevine berry at harvest is a major determinant of wine quality. The composition of the grape berry at harvest is a major determinant of wine quality. It depends on the interactions between the genotypes of the rootstock and of the variety with the global environment around the plant and the microenvironment around the berries. The first growth period, called the herbaceous phase, is characterized by embryo development and cell divisions During this phase, various solutes (malic and tartaric acids, tannins, hydroxycinnamic acids and aroma compounds) accumulate in the different tissues of the berries [2]. Various solutes (malic and tartaric acids, tannins, hydroxycinnamic acids and aroma compounds) accumulate in the different tissues of the berries [2] All these compounds are important for wine quality. Tannins are responsible for the bitter and astringent taste of red wines

Methods

Results

Conclusion