Development of plants enhanced resistance to osmotic stress and Application of proteomic pattern in determining molecular phenotype

Abstract

Abiotic stress caused by high salt concentration, drought and cold inhibits plants` growth and limits productivity of a yield in many important agriculture field. Plant engineering strategies for abiotic stress tolerance rely on the expression of genes that are involved in signaling and regulatory pathways or genes that encode proteins conferring stress tolerance. Therefore, we isolated a new osmotic stress inducible gene, AtSIZ, which encodes a polypeptide with a $C_3H$ type zinc finger. Expression of the gene was induced by exposure of the plants to NaCl, cold temperatures, and dehydrations as well as exogenous application of ABA, although each produced a different pattern of induction. Plants with a T-DNA insertion mutation in the AtSIZ gene showed increased sensitivity to NaCl stress whereas overexpression of AtSIZ enhanced resistance to NaCl stress. Complementation experiments confirmed that the mutant phenotype was caused by the T-DNA insertion in the AtSIZ gene. Expression studies revealed that the mutation in the AtSIZ gene specifically blocked induction of COR15a by NaCl stress but not by cold stress. In contrast, induction of RD29a by both NaCl and cold stresses was normal in the mutant. AtSIZ was able to activate transcription of a reporter gene, gal1-LacZ, in yeast cells when expressed as a fusion protein with the GAL4 DNA binding domain. Deletion experiments showed that the C-terminal region of 45 amino acid residues was not required for activation of the reporter in yeast cells. Taken together, these results strongly suggest that AtSIZ is involved in the osmotic stress response by activating transcription of a subset of osmotic stress inducible genes. We also carried out research on the production of transgenic Agrostis mongolica having resistance to osmotic stress for offering the diversity of commercial application in the development of valuable turf grass varieties. Although the experiments were not fully performed, we confirmed that...