Abstract
In Arabidopsis, the induction of a dehydration-responsive gene, RD22, is mediated by ABA. Previous experiments have established that MYC- and MYB-recognition sites in RD22 promoter function as cis-acting elements in the dehydration-induced gene expression. A MYC-related (bHLH) factor (AtMYC2/RD22BP1) and a MYB-related factor (AtMYB2) have been isolated. We have shown that transgenic plants overexpressing AtMYC2/RD22BP1and/or ATMYB2 cDNA displayed ABA hyper sensitivity. ABA induced gene expression of the RD22 and AtADH1 genes also showed the ABA hypersensitivity. Moreover, knock out mutant of the AtMYC2/RD22BP1gene showed ABA less-sensitivity. These results indicate that both AtMYC2/RD22BP1and AtMYB2 proteins function as transcriptional activators in ABA-inducible gene expression under drought stress in plants. In 2004, AtMYC2 was reported as the JASMONATE-INSENSITIVE1 gene.
In this meeting, we will report the results of gene chip analyses using 35:AtMYC2, 35S:AtMYB2 and 35S:AtMYC2/AtMYB2 plants . We will discuss the function of these factors in ABA and JA signaling
