Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: December 2, 2003
Publication Date: February 19, 2004
Citation: Wisniewski, M.E., Bassett, C.L., Artlip, T.S. 2004. Effect of photoperiod, temperature & drought on the expression of two dehydrin genes in peach. Meeting Abstract. Plant Responses and Abiotic Stress (Abstracts) Pg. 51., 2004. Technical Abstract: Maximum cold hardiness in temperate woody plants is dependent on both dormancy and cold acclimation. While these two processes are not mutually exclusive, they do exhibit independent pathways of signal transduction. Among the many genes that have been linked to freezing tolerance, and other dehydrative stresses, are dehydrin genes. In order to better understand the regulation of dehydrin gene expression in peach, we examined the expression of two tandem dehydrin genes in response to photoperiod, temperature, and drought. One-year-old peach trees were subjected to combinations of short day or long day with either non-acclimating or acclimating temperatures for periods of 3 or 5 weeks. Additional experiments subjected trees to conditions of water deficit and water-deficit recovery. The expression of two tandem peach dehydrin genes (PpDhn1, PpDhn2) were monitored. Our results indicate that PpDhn1 is strongly induced by low temperature but not by short photoperiod while PpDhn2 is moderately induced by both. Both dehydrin genes were strongly induced by water deficit. Promoter analysis indicated that PpDhn1 has C-repeat/DRE motifs, while PpDhn2 does not, although a complementary C-repeat sequence does exist on the non-coding strand of DNA. PpDhn2 has several putative light-responsive elements while none were apparent in the promoter region of PpDhn1. The promoters of both dehydrin genes have ABA-responsive elements, and respond strongly to water deficit. The existence of ABA-responsive, light, and cold elements in the promoter regions of these dehydrin genes may help to explain reports in the literature of both ABA-dependent and independent pathways leading to dormancy and cold acclimation.