Submitted to: Mid Atlantic Plant Molecular Biology Society Conference
Publication Type: Abstract Only
Publication Acceptance Date: August 19, 2002
Publication Date: N/A
Environmental stresses, including low temperature extremes, reduce crop yields and impact the profitability and competitiveness of U.S. producers. The U.S. is the world's leading blueberry producer. The blueberry industry in the U.S. suffers from a lack of winter hardy and spring-frost resistant cultivars. In order to increase our understanding of the genetic control of cold hardiness and ultimately use this information to develop more cold hardy cultivars, our laboratory has been cloning and characterizing expression of cold-responsive genes from blueberry. We have used a molecular genetic approach to identify genes that are up-regulated during cold acclimation and, more recently, have begun using a genomic approach to identify and characterize a much larger group of genes expressed during cold acclimation. Previously, we identified a group of dehydrins (proteins induced by environmental stimuli that have a dehydrative component such as freezing and drought stress) of 65, 60, and 14 kDa that are the predominant up-regulated proteins in cold acclimated floral buds of blueberry. Recent expression studies indicate that (1) blueberry dehydrins are induced by cold stress in all organs, but by drought stress mainly in stems; (2) dehydrin accumulation correlates positively with cold tolerance, but not with drought tolerance; and (3) dehydrin expression in blueberry cell suspension cultures is different from that in whole plants. Several cDNA clones representing members of the dehydrin gene family have been isolated including full-length clones for the 60 and 14 kDa dehydrins. Finally, a genomic approach to the study of cold-responsive genes in blueberry has been undertaken. EST (expressed sequence tag) analysis of a cDNA library representing genes that are expressed mid-winter, when plants have reached their maximum level of cold hardiness, is being used to develop EST-PCR (expressed sequence tag-polymerase chain reaction) markers for mapping purposes and to categorize the types of genes expressed during cold acclimation.