RNA interference-based exogenous double-stranded RNAs confer resistance to Rhizoctonia solani AG-3 on Nicotiana tabacum.

ABSTRACT

BACKGROUND: Rhizoctonia solani Kühn is a pathogenic fungus causing tobacco target spot disease, and leads to great losses worldwide. At present, resistant varieties and effective control strategy on tobacco target spot disease are very limited. Host-induced gene silencing (HIGS) as well as the exogenous dsRNA can be used to suppress disease progression, and reveal the function of crucial genes involved in the growth and pathogenesis of the fungus. RESULTS: The silencing of endoPGs or RPMK1 in host plants by TRV-based HIGS resulted in a significant reduction in disease development in Nicotiana benthamiana. In vitro analysis validated that red fluorescence signals were consistently observed in the hyphae treated with Cy3-fluorescein-labeled dsRNA at 12, 24, 48 and 72 h postinoculation (hpi). Additionally, application of dsRNA-endoPGs, dsRNA-RPMK1 and dsRNA-PGMK (fusion of partial endoPGs and RPMK1 sequences) effectively inhibited the hyphal growth of R. solani YC-9 in vitro and suppressed disease progression in the leaves, and quantitative real-time PCR confirmed that the application of dsRNAs significantly reduced the expression levels of endoPGs and RPMK1. CONCLUSION: These results provide theoretical basis and new direction for RNAi approaches on the prevention and control of disease caused by R. solani. © 2024 Society of Chemical Industry.