Transcript Analysis of Leaf and Shoot Tip Tissue from Cabernet Sauvignon Under a Rapid Dehydration Stress

An abiotic stress that has perhaps the most devastating effect on plant growth and production is drought. For a fruit bearing plant such as grape, responses to drought become even more critical due to the fact that the grapevines must continue to assimilate carbon through photosynthesis for growth and development and at the same time be able to conserve enough water to survive. Therefore the immediate response to dehydration by the leaves and shoot tips requires further investigation. Nimblegen microarrays were used for transcript analysis on tissue from Cabernet Sauvignon (Clone 8). This study consisted of 5 time points over a 24-hour period with replication, totaling 60 samples that were subject to the rapid dehydration. Tissue was dehydrated by suspension above a 300 mM NaCl solution in an enclosed plastic box for the different time periods. For initial analysis, 2-way ANOVA revealed that there were 11,227 and 13,905 transcripts that were affected significantly (p ≤ 0.01) by the treatment in the leaves and shoot tips respectively. Cluster analysis was then performed to separate transcripts into similar expression patterns, which were then functionally categorized to investigate overrepresented GO categories. In leaf samples, the most over represented category for genes that are up regulated rapidly and remain constant belong to the ethylene mediated pathway. In contrast, flavonoid biosynthetic processes were the most significant functional category from a similar cluster containing treatment significant genes from shoot tip samples. Individual genes from these clusters and others will be presented here.