Extracellular perception of multiple novel core effectors from the broad host-range pear anthracnose pathogen Colletotrichum fructicola in the nonhost Nicotiana benthamiana

Abstract

Colletotrichum fructicola is emerging as a devastating pathogenic fungus causing anthracnose in a wide range of horticultural crops, particularly fruits. Exploitation of nonhost resistance (NHR) represents a robust strategy for plant disease management. Perception of core effectors from phytopathogens frequently leads to hypersensitive cell death and resistance in nonhost plants; however, such core effectors in C. fructicola and their signaling components in non-hosts remain elusive. Here, we found a virulent C. fructicola strain isolated from pear exhibits non-adaptation in the model plant Nicotiana benthamiana. Perception of secreted molecules from C. fructicola appears to be a dominant factor in NHR, and four novel core effectors—CfCE4, CfCE25, CfCE61, and CfCE66—detected by N. benthamiana were, accordingly, identified. These core effectors exhibit cell death-inducing activity in N. benthamiana and accumulate in the apoplast. With a series of CRISPR/Cas9-edited mutants or gene-silenced plants, we found the coreceptor BAK1 and helper NLRs including ADR1, NRG1, and NRCs mediate perceptions of these core effectors in N. benthamiana. Concurrently, multiple N. benthamiana genes encoding cell surface immune receptors and intracellular immune receptors were greatly induced by C. fructicola. This work represents the first characterization of the repertoire of C. fructicola core effectors responsible for NHR. Significantly, the novel core effectors and their signaling components unveiled in this study offered insights into a continuum of layered immunity during NHR and will be helpful for anthracnose disease management in diverse horticultural crops.

Acknowledgements

We thank Prof. Yuanchao Wang from Nanjing Agricultural University for sharing the bak1 mutant. We thank Prof. Hailong Guo from China Agricultural University for sharing the eds1 mutant and NahG-transgenic plant that were originally from Prof. Jonathan D.G. Jones’s lab at the Sainsbury Laboratory. We also thank Prof. Xiangxiu Liang from South China Agricultural University for sharing the npr1, adr1, nrg1, and adr1-nrg1 mutants. This work was financially supported by National Natural Science Foundation of China (32302301, U1903206) and the Talent Program of Anhui Agricultural University (rc342213).

Author contributions

J.N. designed and conceived the research. J.N., M.H., C.W., and W.Z. performed the experiments. J.N., M.H., C.W., and W.Z. analysed the data. J.N., M.H., C.W., and W.Z. wrote the manuscript. Y.P. and L.H. critically reviewed this manuscript.

Data availability

All relevant data can be found within the manuscript and its supporting materials.

Conflict of interest statement

The authors declare no conflicts of interest.

Supplementary data

Supplementary data is available at Horticulture Research online.

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