Cloning And Expression Analysis Of Four GmMYB Genes Induced By Abiotic Stresses

Response to external cue is the outcome of stress-induced gene expression. In thispaper, based on one stressed induced EST sequence (259bp, unpublished) we alignwith Soybean genomic database and cloned four R2R3-MYB genes from soybeancultivar Dongnong42, Heinong35and Hefeng25whose sequences consist3exonsand2introns. Three of them corresponding to Gm02g1300, Gm03g38040andGm10g01340respectively are consistent with the sequences of Willams82.30nucleotides insertion/deletion occurred between the first exon and the second exonwhich caused10amino acid insertion/deletion and a single nucleotide polymorphismin the sequence of Gm19g40650from Dongnong42occurred comparing withWillams82which caused a synonymous amino acid substitution (E125-D125).In order to test the relationship of four MYB genes with stress resistance, the seedlingsof cultivar Heinong35or Dongnong42was subjected to abiotic stresses including lowtemperature, drought, salt and alkali controlled by artificial climate chamber. RT-PCRor quantitative PCR analysis suggested that all of the four genes were transientdown-regulated or up-regulated when subjected to abiotic stresses, but different in theexpression time, level and tendency. Gm02g01300was induced by drought stresswhile Gm03g38040was strongly induced by multiple stresses indicated that they playimportant roles on the responding to external stresses. There are also differences in theexpression of individual gene between cotyledons and embryos. These results under avariety of abiotic stress conditions suggested that the four R2R3-MYB genes are notonly different in the expression patterns, but also in the regulation modes.