Plant & Animal Genomes XI Conference Plant & Animal Genomes XI ConferenceJanuary 11-15, 2003
Town & Country Convention Center
San Diego, CA
Poster: Genome Sequencing & ESTs
Development of the grape berry (Vitis vinifera L.) follows a double-sigmoidal growth curve, with the beginning of the second period of growth defining the onset of ripening, or veraison. Little is known about the changes in gene expression leading to veraison. Nevertheless, an EST analysis of a veraison cDNA library from Thompson Seedless berries showed that 25% of the sequences were associated with stress responses; a further 23% are implicated in disease resistance, and nearly 22% are involved in protein turnover. In order to determine how expression of individual genes changes during berry growth and development it is necessary to compare expression at different developmental stages. We have attempted to derive quantitative gene expression information using real-time RT-PCR on RNA samples isolated from Thompson Seedless grape berries at five stages of development. Strategies for quantitative gene expression such as real-time RT-PCR require a constitutively-expressed reference gene against which expression of other genes can be normalised. A suitable reference gene may be particularly difficult to identify in tissue undergoing major developmental change, or if little functional information is available about the tissue. Some of the more traditional normalising gene candidates such as actin, aquaporin, ubiquitin and rRNA genes seem to show variation in expression across the range of berry development studied. This may be because the developing grape berry undergoes dramatic changes in cell size, cell physiology, cellular metabolism and physiological state. The objective of this work is to identify a normalising gene that can be used for the study of relative gene expression within tissues of developing fruit that typically undergo substantial developmental change throughout the experimental period.