Date: Sunday, January 15, 2012
Time: 1:30 PM
Time: 1:30 PM
Room: Pacific Salon 6-7 (2nd Floor)
The ripening process in the grape cluster starts as an asynchronous process, with three to four berry classes at various ripening states at the onset of ripening (véraison). In some cultivars these berry classes show uniformity in their phenological ripening states at harvest. In Pinot noir asynchronous cluster, we identified four berry classes at different levels of ripening and examined the level of transcriptional variability among berry classes through whole genome microarrays. By tagging véraison berry classes in the same clusters and by tracking them to harvest, we performed a second set of transcriptomes and observed a significant reduction of the variability among berry classes. Models of gene expression dynamics were designed by comparing transcriptomes between berry classes (green, pink, red) and between developmental stages (véraison and harvest). One model, where no difference between véraison and harvest red berries was observed, suggests that a steady-state transcript level had been reached at red stage where green and pink berries would be at the end of véraison. However, in other gene models where transcript abundance of red berries between véraison and harvest time points was either on ascending or descending slope, a transcriptional readjustment among berry classes must occur to enable the reduction of transcriptional variability by harvest time point. Considering the time required for veraison green and pink berries to reach red berry equivalent state, the transcription of those genes, thereafter, must be at increased or decreased rate compared to that of véraison-to-harvest transcriptional rate of red berries for synchronization.