Broad-Spectrum Disease Control and Enhanced Resilience in Wheat via an Endophytic Biocontrol Fungus

Wheat production is threatened by many destructive diseases, particularly Fusarium crown rot (FCR) and Fusarium head blight (FHB), for which effective control strategies are urgently needed. Here, we systematically screened 28 Clonostachys spp. strains for biocontrol efficacy against FCR and identified Clonostachys chloroleuca strain Cc620 as a highly promising agent. Cc620 exhibited strong mycoparasitic activity against Fusarium pathogens and functioned as an endophyte primarily colonizing wheat roots. Seed treatment with Cc620 significantly promoted wheat seed germination, root development, and enhanced resistance to both FCR and FHB under greenhouse and multi-location field conditions. Furthermore, the Cc620 application improved agronomic traits of wheat in fields and suppressed a broad spectrum of wheat and soybean diseases. Genomic and transcriptomic analyses revealed that Cc620 induces extensive metabolic reprogramming and upregulates defense-related pathways in wheat, including key immune regulators such as TaWRKY33. Moderate overexpression of TaWRKY33 in wheat conferred increased resistance to both FCR and FHB without a yield penalty. Field surveys confirmed the natural occurrence and strong colonization potential of C. chloroleuca in major wheat-growing regions. Our findings demonstrate that Cc620 is a robust and sustainable biocontrol agent, offering a promising alternative for integrated disease management in wheat production.