A conserved double‐W box in the promoter of <i>CaWRKY40</i> mediates autoregulation during response to pathogen attack and heat stress in pepper
Z. Liu, Lanping Shi, Sheng Yang, Shan Shan Qiu, Xiaoling Ma, Jinsen Cai, Deyi Guan, Zonghua Wang, Shuilin He
Abstract
Abstract CaWRKY40 was previously found to be transcriptionally up‐regulated by Ralstonia solanacearum inoculation (RSI) or heat stress (HS), but the underlying mechanism remains unknown. Herein, we report that a double‐W box‐element (DWE) in the promoter of CaWRKY40 is critical for these responses. The upstream W box unit WI of this composite element is crucial for preferential binding by Ca WRKY40 and responsiveness to RSI or HS. DWE‐driven CaWRKY40 can be transcriptionally and nonspecifically regulated by itself and by Ca WRKY58 and Ca WRKY27. The DWE was also found in the promoters of CaWRKY40 orthologs, including AtWRKY40 , VvWRKY40 , GmWRKY40 , CplWRKY40 , SaWRKY40 , SpWRKY40 , NtWRKY40 , and NaWRKY40 . DWE AtWRKY40 was analogous to DWE CaWRKY40 by responding to RSI or HS and At WRKY40 expression. These data suggest that a conserved response of plants to pathogen infection or HS is probably mediated by binding of the DWE by WRKY40.