Cloning And Function Analysis Of Salt Responsive Genes TaSRHP And TaSMP In Wheat

Salinity in soil or water greatly reduces plant growth and crop productivity worldwide. More than 800 million hectares of land in the world are salt-affected, equating to more than 6% of the world’s total land area. With the development of molecular biology, cloning salt-tolerant genes and improving salt tolerance of transgenic plant by the overexpression of the genes has been widely recognized. The purpose of the article lies in cloning salt-tolerant genes in wheat and analysising their function to provide reference for the study of molecular mechanism involved in salt tolerance of plants. The main results are as follows:1. Cloning and functional analysis of the wheat salt-tolerant gene TaSRHPAccording to the microarray analysis, a probe sequence corresponding to increased expression under salt stress was choosed. The full-length cDNA sequence was cloned through e-cloning and RT-PCR. This cDNA contains a 429bp complete open reading frame which is an unknown protein named TaSRHP. TaSRHP contains an unknown function domain DUF581 which there is less work about it. Senescence-related gene SAG102 contains the same function domain DUF581. Dark and ABA stress influenced the germination of the mutant. Therfore, we suppose TaSRHP may have the same function involving in molecular regulation under abiotic stress response.The Arabidopsis transgenic plants overexpressing TaSRHP showed increased tolerance to salt. Under NaCl treatment, the transgenic seedlings formed longer roots and had better survival rate than the wild type.Interestingly, TaSRHP may involved in the response to salt stress and dark. Treating with NaCl and dark, the seed germination of homozygous transgenic lines were better than that of the wildtype plants. TaSRHP may have the same function with SAG102 involving in molecular regulation under abiotic stress response.Before and after salt treatments, TaSRHP overexpressing plants accumulated higher contents of proline than the wild type. It is supposed that TaSRHP induced the expression of P5CS, increasing the contents of proline.It can partly explain transgenic plants overexpressing TaSRHP showed increased tolerance to salt.It shows that TaSRHP is the upstream gene of AADH,KIN2,RD29B,COR15a and participates CDPK pathway.2. Cloning and functional analysis of the wheat salt-tolerant gene TaSMPAccording to cDNA-AFLP analysis, a probe sequence corresponding to increased expression under salt stress was choosed. The full-length cDNA sequence was cloned through e-cloning and RT-PCR. This cDNA contains a 1593bp complete open reading frame which is an unknown protein named TaSMP. TaSMP shares 82% homology of nucleic acid with a rice gene(Os06g0223700). The Arabidopsis transgenic plants overexpressing TaSMP showed increased tolerance to salt. Before and after salt treatments, TaSMP overexpressing plants accumulated higher contents of proline than the wild type. The increasing of contents of proline further confirmed transgenic plants overexpressing TaSMP showed increased tolerance to salt.It shows that TaSMP is the upstream gene of AADH,KIN2,RD29B,COR15a and participates CDPK pathway.