Gene expression variation in grapevine species Vitis vinifera L. and Vitis aestivalis Michx.

Comparative microarray (Vitis GeneChip) analysis in young leaves revealed considerable variation in gene expression between Vitis vinifera L. and Vitis aestivalis Michx. Approximately 12% of the genes were differentially expressed in the two grapevine species (P < 0.001). Over 200 probe sets were identified which consistently detected transcripts in one grapevine species, but not in the other. We were unable to identify any broad functional category in which transcript abundance was overall different in any one species. Of the genes expressed only in V. aestivalis leaves, we identified a class IV chitinase which was previously shown by others to have a flower- and fruit-specific expression in V. vinifera. Among the transcripts which were differentially expressed (P < 0.001) in both species, we identified genes encoding key enzymes in flavonoid, monolignol, and proanthocyanindin biosynthesis. Statistical exploration of the data suggested that sequence divergence between the predominantly V. vinifera-derived GeneChip probes and the V. aestivalis cRNA did not confound the hybridization data and that the reliability of the microarray results was similar in the two grapevine species.