2013 Annual Report
Many plants have been able to adapt to periods of extreme weather stress by creating new sets of genes with altered expression. These genes are poised to respond to a variety of stress events, and because they are associated with survival on land, they are well conserved in most higher plants, including important crops. Studing the differences and similarities in the expression of these stress-responsive genes in related crops, such as apple and grape, will help identify which genes contribute the most to drought tolerance. The objective of this collaborative arrangement (grape studies at NAFU and apple studies at AFRS) is two-fold: .
Identified a family of genes in apples that is associated with early response to a number of environmental stresses. This family, SBP-box (Squamosa binding protein), consists of 27 members, many of which were responsive to well known plant stress hormones. A paper describing these results was recently accepted for publication in a peer-reviewed journal. We plan to continue these studies to include comparison of the promoter regions of the individual family members to identify sequences responsible for regulation of the expression of these genes.
We have also identified a family of 50 genes involved in protein degradation in grape. The enzymes encoded by these genes belong to the Aspartic Protease (AP) class and appear to function both in stress responses as well as during plant development. Protein turnover is a key mechanism for regulating the final expression of a given gene. Fifty different genes encoding Aps in grape were identified and their expression in response to various stress treatments determined. Some family members were more responsive to drought than salt, while others were more responsive to salt. Expression in response to the plant stress hormones was also determined with some overlap in response observed. A manuscript describing the different grape family members and their expression in response to drought and salt treatment is currently being revised in preparation for publication.