Chilean effort for improving fruit quality in grapevine: A genomic approach to understanding seed formation, fruit ripening and pathogen response

Improving fruit quality is a priority for the Chilean grape industry. A national effort has begun using the genomic approach to study problems related to seed formation, fruit ripening and the vine's response to Botrytis cinerea infection. Seedless cultivars such as 'Thompson Seedless' have embryo abortion at an early stage of berry growth impairing seed formation and subsequently affecting the size of the berry. To obtain berries of commercial size, vineyards are sprayed with gibberellic acid (GA₃). The genes and/or biological processes controlling embryo abortion and fruit size, as well as the response of berries to GA₃ applications in this and other cultivars are unknown. On the other hand, wine grape cultivars such as 'Carménè re' also have problems related to seed formation and berry development. Clusters containing a certain percentage of underdeveloped parthenocarpic berries can negatively affect wine quality. The causes for this are also poorly understood. Finally, berries of both 'Thompson Seedless' and 'Carménère' are affected by Botrytis cinerea. It appears that 'Carménère' is more tolerant to the infection than 'Thompson Seedless'. The genes and/or biological processes regulating these responses are unknown. We have begun a functional genomics approach towards defining the changes that occur during fruit development in both cultivars. We are in the process of sequencing approximately 100,000 ESTs from flowers and fruits collected at different developmental stages, and either sprayed or not sprayed with GA₃. The clones and sequence information generated will be used to analyze the global gene expression using macroarray analyses. Related information can be found at the web site of The Grape Functional Genomic Project-Chile (DEGECHIVID) http://www.genomicafrutos.cl.