Exogenous Application of dsRNA—Inducing Silencing of the Fusarium oxysporum Tup1 Gene and Reducing Its Virulence

Fusarium oxysporumis a widespread soil-borne fungal pathogen that can infect various plants, causing wilt and root rot diseases. The root rot disease ofAtractylodes macrocephalacaused byF. oxysporumis among the most serious diseases associated with continuous cropping, significantly hindering its sustainable development. In this study, we aimed to investigate the effect of exogenous application of double-stranded RNA (dsRNA) on silencing theF. oxysporum Tup1gene to reduce its virulence and to evaluate its potential application in controlling root rot disease inA. macrocephala. TheTup1gene was amplified from theF. oxysporumgenome, and different lengths ofTup1-dsRNA were designed and synthesized. The uptake of dsRNA by the fungus was verified usingTup1-dsRNA labeled with fluorescein, and in vitro dsRNA treatment experiments were conducted to assess its impact on the growth and virulence ofF. oxysporum. Additionally,Tup1-dsRNA was applied to the roots ofA. macrocephalato evaluate its effectiveness in controlling root rot disease. The experimental results showed thatF. oxysporumcould effectively uptake exogenously appliedTup1-dsRNA, significantly reducingTup1gene expression. All lengths ofTup1-dsRNA inhibited fungal growth and caused morphological changes in the fungal hyphae. Further plant experiments and Reverse Transcription Quantitative Polymerase Chain Reaction (RT-qPCR) analysis indicated thatTup1-dsRNA treatment significantly reduced the incidence of root rot disease inA. macrocephala, which was supported by the reduction in peroxidase (POD) and catalase (CAT) enzyme activities, malondialdehyde (MDA) content, and proline (Pro) levels in treated root tissues. This study demonstrated that exogenous dsRNA could reduce the virulence ofF. oxysporumby silencing theTup1gene and effectively mitigate the root rot disease it causes inA. macrocephala. The successful application ofTup1-dsRNA provided strong evidence for the potential of RNA interference (RNAi) technology in plant disease control. Future research could further optimize the design and application of dsRNA to enhance its practical value in agriculture.