Expression And Functional Identification Of Stress-Responsive Related Genes From Wheat

Drought, high salt, cold are common abiotic stress conditions that adversely affect wheat growth andproduction. So, it has important meaning to research and breed wheat which could decrease the hurt ofabiotic stress.The wheat seedings were treated by drought, cold, salt, ABA and powdery mildew respectively, thenthe total RNA were separately isolated from these wheat seedings leaves. The transcriptionfactors--DREB4 and EREB1 were obtained from the cDNA library of drought-treated wheat seedings byphage hybridization in situ. Northern blot analysis indicated that the expressions of DREB4 and EREB1were all upregulated by drought and salt. DREB4 gene was induced to express within 5 h after exposure todrought, and the gene expression arrived at its peak after 10 h. Significant mRNA accumulation of DREB4was observed within 2 h, when subjected high-salt stress, the mRNA accumulation strongly increased after10 h. EREB1 gene was induced within 2 h by drought and high-salt, and the expressions were graduallyincreased with prolonging stresses. DREB4 and EREB1 were not induced by ABA and cold. EREB1 genewas induced by powdery mildew, the gene expression was induced after 24 h and arrived at its peak after48 h. But DREB4 gene was not induced by powdery mildew.DREB4 and EREB1 were transformed into arabidopsis using the agrobacterium-mediatedtransformation method. The transgenic arabidopsis plants were treated with drought, cold and salt, theresults indicated that the livabilities of the transgenic plants with DREB4 and EREB1 were all higher thanwild-type arabidopsis under drought, cold and salt. And the transgenic plants with DREB4 had bettertolerance than EREB1 under drought and salt. In addition, DREB4 and EREB1 genes were also introducedinto tobacco, and the plants with DREB4 and EREB1 were obtained. These transgenic plants with DREB4are being analyzed under drought and salt condition respectively.A water stress-induced gene (designated as W89) was isolated from the cDNA library ofdrought-treated wheat seedings. The full-length cDNA of W89 consisting of 1059 bp and containing a 696bp open reading frame (ORF) encoded a 232-amino-acid protein. Southern blot analysis indicated that W89was a single-copy gene. RT-PCR analysis revealed that the expression of W89 was upregulated by abscisicacid (ABA), drought and cold. The highest expression levels of W89 were induced by ABA and cold formore than 5 hrs, and by drought treatment for more than 2 hrs.Amino acid sequence analysis showed that W89 had a conserved region of DUF248, which containeda methyltrasferase domain with a SAM-binding motif. Phylogenetic analysis showed that W89 was 66%identical to Oryza sativa dehydration-responsive protein (BAD67956). It was supposed that W89 was anovel dehydration-responsive protein encoding gene. Based on the functions of methyltrasferase andSAM-binding motif, the SAM-binding motif of W89 was supposed to interact with other proteins ortranscription factors to transduct stress signals and finally regulated the expression of stress-responsivegenes on the early time of drought stress.The expression analysis and functional analysis of stress-responsive related genes from wheatprovided prooves to undertand the expression regulation of genes under abiotic stress, and estabishedfundation to analysis the transduction of stress signals. The stress-responsive related genes—DREB4,EREB1, W89 maybe provided fine genes for improving crop to resist abiotic stress.