CsBZIP40 confers resistance against citrus bacterial canker by repressing CsWRKY43-CsPrx53/CsSOD13 cascade mediated ROS scavenging

Qiang Li; Xiujuan Qin; Miao Zhang; Qiyuan Yu; Ruirui Jia; Jie Fan; Xin Huang; Jia Fu; Chenxi Zhang; Baohang Xian; Wen Yang; Qin Long; Aihong Peng; Lixiao Yao; Shanchun Chen; Yongrui He

doi:10.1093/hr/uhad138

CsBZIP40 confers resistance against citrus bacterial canker by repressing CsWRKY43-CsPrx53/CsSOD13 cascade mediated ROS scavenging

Hortic Res. 2023 Jul 11;10(8):uhad138. doi: 10.1093/hr/uhad138. eCollection 2023 Aug.

Authors

Qiang Li^{1

2

3}, Xiujuan Qin¹, Miao Zhang¹, Qiyuan Yu¹, Ruirui Jia¹, Jie Fan¹, Xin Huang¹, Jia Fu¹, Chenxi Zhang¹, Baohang Xian¹, Wen Yang¹, Qin Long^{1

2

3}, Aihong Peng^{1

2

3}, Lixiao Yao^{1

2

3}, Shanchun Chen^{1

2

3}, Yongrui He^{1

2

3}

Affiliations

¹ Citrus Research Institute, Southwest University/Chinese Academy of Agricultural Sciences, Beibei, Chongqing 400712, China.
² National Citrus Engineering Research Center, Beibei, Chongqing 400712, China.
³ National Citrus Improvement Center, Southwest University, Chongqing 400712, China.

Abstract

As the bacterial etiologic agent causing citrus bacterial canker (CBC), Xanthomonas citri subsp. citri (Xcc) seriously impacts citrus plantation and fruit production globally. In an earlier study, we demonstrated that CsBZIP40 can positively impact CBC resistance in the sweet orange (Citrus sinensis). However, the mechanistic basis for the protective benefits conferred by CsBZIP40 is yet to be delineated. Here, we show that CsBZIP40 positively regulates CBC resistance and reactive oxygen species (ROS) homeostasis in transgenic sweet orange overexpressing CsBZIP40. CsBZIP40 directly binds to the TGA-box of the CsWRKY43 promoter to repress its transcriptional activity. CsWRKY43 overexpression induces CBC susceptibility in transgenic sweet oranges. In contrast, its inhibition produces strong resistance to CBC. CsWRKY43 directly binds to the W-boxes of the CsPrx53 and CsSOD13 promoters to positively regulate the activities of these antioxidant enzymes, resulting in the negative regulation of ROS homeostasis and CBC resistance in sweet orange plants. CsPrx53/CsSOD13 knockdown enhances ROS accumulation and CBC resistance. Overall, our results outline a regulatory pathway through which CsBZIP40 transcriptionally represses CsWRKY43-CsPrx53/CsSOD13 cascade-mediated ROS scavenging in a manner conducive to CBC resistance. These mechanisms underscore the potential importance of CsBZIP40, CsWRKY43, CsPrx53, and CsSOD13, providing promising strategies for the prevention of CBC.