Host‐induced gene silencing is a promising biological tool to characterize the pathogenicity of Magnaporthe oryzae and control fungal disease in rice.

The rice blast fungus Magnaporthe oryzae is a devastating plant pathogen that threatens rice production worldwide. Host‐induced gene silencing (HIGS) has been effectively applied to study pathogenic gene function during host–microbe interactions and control fungal diseases in various crops. In this study, the HIGS system of M. oryzae was established using transgenic fungus expressing green fluorescence protein (GFP), KJ201::eGFP and 35S::dsRNAi plants, which produce small interfering RNAs targeting fungal genes. Through this system, we verified the HIGS of rice blast fungus quantitatively and qualitatively in both Arabidopsis and rice. Then, we showed that the HIGS of M. oryzae's pathogenic genes, including RGS1, MgAPT2 and LHS1, significantly alter its virulence. Both 35S::dsRNAi_MgAPT2 and 35S::dsRNAi_LHS1 plants showed a considerably enhanced fungal resistance, characterized by the formation of H2O2‐containing defensive granules and induction of rice pathogenesis‐related (PR) genes. In addition, the enhanced susceptibility of 35S::dsRNAi_RGS1 plants to blast fungus suggested a novel mode of action of this gene during fungal infection. Overall, the results of this study demonstrate that HIGS is a very effective and efficient biological tool not only to accurately characterize the functions of fungal pathogenic genes during rice‐M. oryzae interactions, but also to control fungal disease and ensure a successful rice production. Summary statement: This study demonstrates that host‐induced gene silencing (HIGS) is effective in generating fungus‐resistant crops and characterizing the biological functions of fungal pathogenic genes during plant–microbe interactions. We verified the cross‐kingdom movement of small interfering RNAs from host plants to Magnaporthe oryzae and the silencing of fungal genes. The HIGS of three M. oryzae pathogenic genes, RGS1, MgAPT2 and LHS1, significantly modified the virulence of the fungus suggesting that the functions of these genes are involved in determining the types of plant–microbe interactions, that is, whether they are compatible or incompatible. [ABSTRACT FROM AUTHOR]