1. Mitochondrial‐targeting effector RsIA_CtaG/Cox11 in Rhizoctonia solani AG‐1 IA has two functions: plant immunity suppression and cell death induction mediated by a rice cytochrome c oxidase subunit.
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Zhang, Danhua, Lin, Runmao, Yamamoto, Naoki, Wang, Zhaoyilin, Lin, Hui, Okada, Kazunori, Liu, Yao, Xiang, Xing, Zheng, Tengda, Zheng, Haoxi, Yi, Xiaoqun, Noutoshi, Yoshiteru, and Zheng, Aiping
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CYTOCHROME oxidase , *CELL death , *RHIZOCTONIA solani , *DISEASE resistance of plants , *RNA interference , *RICE diseases & pests - Abstract
Rhizoctonia solani AG‐1 IA causes a necrotrophic rice disease and is a serious threat to rice production. To date, only a few effectors have been characterized in AG‐1 IA. We previously identified RsIA_CtaG/Cox11 and showed that infiltration of the recombinant protein into rice leaves caused disease‐like symptoms. In the present study, we further characterized the functionality of RsIA_CtaG/Cox11. RsIA_CtaG/Cox11 is an alternative transcript of cytochrome c oxidase copper chaperone Cox11 that starts from the second AUG codon, but contains a functional secretion signal peptide. RNA interference with RsIA_CtaG/Cox11 reduced the pathogenicity of AG‐1 IA towards rice and Nicotiana benthamiana without affecting its fitness or mycelial morphology. Transient expression of the RsIA_CtaG/Cox11‐GFP fusion protein demonstrated the localization of RsIA_CtaG/Cox11 to mitochondria. Agro‐infiltration of RsIA_CtaG/Cox11 into N. benthamiana leaves inhibited cell death by BAX and INF1. In contrast to rice, agro‐infiltration of RsIA_CtaG/Cox11 did not induce cell death in N. benthamiana. However, cell death was observed when it was coinfiltrated with Os_CoxVIIa, which encodes a subunit of cytochrome c oxidase. Os_CoxVIIa appeared to interact with RsIA_CtaG/Cox11. The cell death triggered by coexpression of RsIA_CtaG/Cox11 and Os_CoxVIIa is independent of the leucine‐rich repeat receptor kinases BAK1/SOBIR1 and enhanced the susceptibility of N. benthamiana to AG‐1 IA. Two of the three evolutionarily conserved cysteine residues at positions 25 and 126 of RsIA_CtaG/Cox11 were essential for its immunosuppressive activity, but not for cell death induction. This report suggests that RsIA_CtaG/Cox11 appears to have a dual role in immunosuppression and cell death induction during pathogenesis. [ABSTRACT FROM AUTHOR]
- Published
- 2024
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