USING FUNCTIONAL AND APPLIED GENOMICS TO IMPROVE STRESS AND DISEASE RESISTANCE IN FRUIT TREES
Location: Appalachian Fruit Research Laboratory: Innovative Fruit Production, Improvement and Protection
Title: Differential transcription initiation of dehydrin 1 (PpDhn1) and dehydrin 2 (PpDhn2) in peach fruit is stage-dependent
Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: October 2, 2007
Publication Date: October 19, 2000
Citation: Bassett, C.L., Richart, G.A., Artlip, T.S., Wisniewski, M.E., Farrell, Jr., R.E. 2000. Differential transcription initiation of dehydrin 1 (PpDhn1) and dehydrin 2 (PpDhn2) in peach fruit is stage-dependent. Meeting Abstract, symposium on RNA Biology VII: RNA, Tool and Target. pg 31.
Dehydrins are plant-specific proteins that respond to environmental stresses related directly to dehydration, such as drought or that have dehydration as a component, as with freezing temperatures. The genes encoding the dehydrins are comprised of a small family with individual members showing differential or combinatorial responses to various stresses. We have studied the expression of two peach (Prunus persica L. Batsch) dehydrins in some detail under both field conditions and carefully controlled light/temperature/water regimes. Although PpDhn1 is structurally and functionally distinct from PpDhn2, both cognate proteins share a common, conserved lysine-rich domain ('K' domain), and both are predominantly expressed in bark tissue. Recently, we obtained approximately 1,000 base pairs of sequence information representing the regulatory and other elements upstream of the translation start site. Multiple potential TATAA box elements in the promoters of these two genes suggested that transcription could initiate in different regions and might show treatment- or tissue-specificity. The transcript start sites (TSS) for both genes were mapped by 5'-RLM-RACE using RNA from winter and summer bark and from fruit at different stages of development. The TSS for both genes were essentially the same in bark sampled in winter and summer. In contrast, PpDhn1 in very young fruit initiated much further upstream compared to the bark TSS, whereas, in older fruit the TSS was identical to that observed in bark. In contrast, PpDhn2 transcription initiated further upstream in older, fully ripe fruit compared to younger fruit or to bark. The implications of these observations suggest a post-transcriptional regulatory mechanism influencing expression of these two dehydrins in peach.