Poster: Water relations

Abs # 157: Comparative transcriptional profiling of developing endosperms in maize mutant, viviparous1 and wildtype under water deficit

Presenter:	Yu, Long-Xi , ly15@cornell.edu
Authors	Yu, Long-Xi  (A)   Setter, Tim L (A)
Affiliations:	(A): Cornell University

Maize kernel development at the early post-pollination phase is particularly sensitive to water deficit stress. To determine the extent of involvement of the ABA response factor Vp1 in regulation during the cell division phase of endosperm development, we compared transcriptional profiles of maize developing endosperms between ABA-insensitive mutant, viviparous1(vp1), and wildtype(wt) under water stress using cDNA microarray. At 10 days after pollination, endosperms differed considerably in their transcriptional responses. In wt, 156 transcripts were significantly affected by the stress and of these 70 were up-regulated and 86 were down-regulated. More than 90% of these genes were not affected in vp1 mutant, indicating a strong effect of Vp1 on transcriptional response to the stress. In contrast, in vp1 a different set of transcripts, including 75 up-regulated and 63 down-regulated, were affected by the stress. Of those identified in wt and vp1, about 50% were previously known-function, including common stress responses, cell division and growth related genes, transcription factors and signal transduction proteins, and a large group of genes related to various metabolic pathways and protein synthesis and destinations. The rest were unknown function. Hierarchical cluster analysis provided further support for the finding that different sets of genes were regulated in vp1 and wt endosperm by the same stress condition.