Poster: Salinity

Abs # 170: Expression of HVA1, a barley group III LEA protein, in Saccharomyces cerevisiae confers salt resistance.

Presenter:	Yeh, Ching-Hui , yehch63@yahoo.com
Authors	Yeh, Ching-Hui  (A)   Dittmer, Travis  (A)   Ho, Tuan-Hua David  (A)
Affiliations:	(A): Department of Biology, Washington University

Late embryogenesis abundant (LEA) proteins are ubiquitous in plants and accumulated during the late stage of seed formation and in vegetative tissues under drought, heat, cold, and salt stress conditions or with ABA application. HVA1, a barley group III LEA protein, is highly induced by ABA/stress and its homologs are present in all plants so far checked. The group III LEA proteins are characterized by 11 amino acid tandem repeats (TAQAAKEKAGE). Lately, several reports demonstrated that overexpression of HVA1 in transgenic plants leads to elevated tolerance to water-deficit stress. Here we have established a convenient system to assay for HVA1 function and test the roles of conserved repeats in HVA1. We compare the titer of yeast cultures expressing a recombinant vector containing HVA1 (pYPR3831X-HVA1 cells) with the control yeast cells containing an empty vector (pYPR3831X cells) or expressing a class I small heat shock gene, Oshsp16.9 (pYPR3831X-Oshsp16.9 cells) under salt stress. The pYPR3831X-HVA1 cells show resistance in a medium containing 1.0 M NaCl, that inhibits the growth of pYPR3831X cells and pYPR3831X-Oshsp16.9 cells. Stress resistance level similar to pYPR3831X-HVA1 cells is obtained in pYPR3831X-HVA1N1-102 cells (cells expressing the N-terminal 102 amino acids in the HVA1 portion) but not in pYPR3831X-HVA1N105-213 cells (cells expressing the C-terminal 109 amino acids in the HVA1 portion). These observations suggest that the first half of HVA1 is more important for providing function than of the other half of HVA1.