Plant, Animal & Microbe Genomes X Conference

January 12-16, 2002
Town & Country Convention Center
San Diego, CA

Poster: Genome Sequencing & ESTs
            

CHARACTERISATION AND ANALYSIS OF GENE EXPRESSION DURING THE RIPENING OF GRAPE BERRIES (VITIS VINIFERA L. CV. THOMPSON SEEDLESS)

¹ U.C. Davis Dept of Viticulture and Enology, 1 Shields Ave, Davis, CA, 95616, USA

² USDA/ARS, 800 Buchanan St, Albany, CA, 94710, USA

Development of the grape berry (Vitis vinifera L.) has been described as following a double-sigmoidal growth curve, with the resumption of the second period of growth defining the onset of ripening, called veraison. While physiological events such as colour change, xylem disrupture and sugar accumulation are well established, little is known about the global gene expression profile that occurs at veraison. EST clones isolated from a veraison cDNA library made from the cultivar Thompson Seedless were categorised based on sequence homology and grouped into functional categories. Initial analyses of ESTs for which a function could be assigned indicate that a surprising 25% of those sequences are associated with stress responses; a further 23% are implicated in disease resistance, and nearly 22% are involved in protein processing and turnover. Furthermore, 23% of the total transcripts expressed at the onset of ripening fall into the unknown category, and some individual genes account for as much as 5% of the total ESTs. The high proportions of transcripts for stress responses, disease resistance and protein turnover point to the importance of several physiological processes that are not typically associated with ripening. Work is currently underway to determine how expression of certain members of these functional categories changes during grape berry ripening.