An effector of a necrotrophic fungal pathogen targets the calcium-sensing receptor in chloroplasts to inhibit host resistance.

Liguang Tang, Guogen Yang, Ming Ma, Xiaofan Liu, Bo Li, Jiatao Xie, Yanping Fu, Tao Chen, Yang Yu, Weidong Chen, Daohong Jiang, Jiasen Cheng

Molecular plant pathology 2020 May

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SsITL, a secretory protein of the necrotrophic phytopathogen Sclerotinia sclerotiorum, was previously reported to suppress host immunity at the early stages of infection. However, the molecular mechanism that SsITL uses to inhibit plant defence against S. sclerotiorum has not yet been elucidated. Here, we report that SsITL interacted with a chloroplast-localized calcium-sensing receptor, CAS, in chloroplasts. We found that CAS is a positive regulator of the salicylic acid signalling pathway in plant immunity to S. sclerotiorum and CAS-mediated resistance against S. sclerotiorum depends on Ca2+ signalling. Furthermore, we showed that SsITL could interfere with the plant salicylic acid (SA) signalling pathway and SsITL-expressing transgenic plants were more susceptible to S. sclerotiorum. However, truncated SsITLs (SsITL-NT1 or SsITL-CT1) that lost the ability to interact with CAS do not affect plant resistance to S. sclerotiorum. Taken together, our findings reveal that SsITL inhibits SA accumulation during the early stage of infection by interacting with CAS and then facilitating the infection by S. sclerotiorum. © 2020 Huazhong Agricultural University. Molecular Plant Pathology published by British Society for Plant Pathology and John Wiley & Sons Ltd.

Citation

Liguang Tang, Guogen Yang, Ming Ma, Xiaofan Liu, Bo Li, Jiatao Xie, Yanping Fu, Tao Chen, Yang Yu, Weidong Chen, Daohong Jiang, Jiasen Cheng. An effector of a necrotrophic fungal pathogen targets the calcium-sensing receptor in chloroplasts to inhibit host resistance. Molecular plant pathology. 2020 May;21(5):686-701