Arabidopsis WRKY26 transcription factor regulates ORA47 gene expression involving in wounding signaling
Date Issued
2015
Date
2015
Author(s)
Lee, Chia-Ying
Abstract
Jasmonates (JAs) are plant signaling molecules that play important roles in defense against insects and necrotrophic pathogens. The JA signaling pathway is relatively well studied. In our lab, Arabidopsis ORA47 was demonstrated to be the direct upstream regulator of many JA biosynthetic genes by recognizing a novel cis-element, (AC/GT)CGNCCA, in their promoters. Furthermore, MYC2 was proved to be the direct upstream regulator of ORA47 by recognizing the G-box in its promoter. Gene expression analysis shows that ORA47 and JA biosynthesis genes are all up regulated in 35S::MYC2-GFP overexpression transgenic plants, but are not down regulated in myc2 knockout mutants. Therefore, we believed that there are other transcription factors which regulate ORA47 gene expression. In this study, I confirmed that Arabidopsis WRKY26 could recognize the W-box-like cis-acting sequences, TTGATC, inthe ORA47 promoter region by EMSA, transactivation assay and ChIP assay. We suggested WRKY26 may also involve in wound-induced JA signaling via regulated ORA47 gene expression. Gene expression analysis shows that ORA47 and JA biosynthesis genes are all up regulated in 35S::WRKY26-GFP overexpression transgenic plants but down regulated in wrky26 knockdown mutants. Also, 35S::WRKY26-GFP overexpression transgenic plants show JA-related phenotype while wrky26 knockdown mutants show no difference compared with wildtype. This study reveals that WRKY26 recognizes the W-box-like cis-acting sequence in the ORA47 promoter region and is involved in wound-induced JA signaling.
Subjects
Arabidopsis
wound
jasmonates
Type
thesis
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