Poster: Temperature responses

Abs # 147: Dehydration induces expression and alternative splicing of Dehydrin 1 in V. riparia and V. vinifera tissues

Presenter:	Xiao, Huogen , hxiao@uoguelph.ca
Authors	Xiao, Huogen  (A)   Nassuth, Annette  (A)
Affiliations:	(A): Department of Botany, University of Guelph

Dehydrins are proteins that accumulate in vegetative tissues subjected to various dehydrating stress conditions such as cold, drought and salinity and in seeds at later stages of embryogenesis. Here we report on the expression of DHN1 in wild and cultivated grapes, V. riparia and V. vinifera, in different tissues and under different environmental conditions. Two DHN1 genes, DHN1a and DHN1b, were identified in both V. riparia and V. vinifera. Both genes contain an intron and encode an YSK2 dehydrin when the intron is spliced out. DHN1a was expressed in leaves, buds and seeds in both V. riparia and V. vinifera, whereas DHN1b was expressed only in buds and seeds of V. vinifera. Spliced transcripts, DHN1-S, and unspliced transcripts, DHN1-U, were detected. The expression of DHN1a-S was low in leaves, but high in buds and seeds of both V. riparia and V. vinifera. DHN1a-U was expressed in buds of V. riparia, but not in buds of V. vinifera. Both DHN1b-S and DHN1b-U were expressed only in buds and seeds of V. vinifera. Leaves were subjected to several treatments. DHN1a-S accumulated to high levels after drought, ABA and short-day treatment, but not after cold treatment. DHN1a-U was induced and accumulated to high levels after cold, drought, but not by ABA and short-day treatment. Unspliced transcripts potentially produce a 5.4 KD K2 dehydrin, which would be the smallest dehydrin in plants. The possible relation of these results with the difference in water stress tolerance between V. riparia and V. vinifera will be discussed. This research was supported by Chateau des Charmes wineries, NRC-IRAP, FSBC