Table 2_Laboratory screening and field validation of Myxococcus fulvus and Cystobacter fuscus for the biocontrol of wheat Fusarium Crown Rot.docx

Fusarium Crown Rot (FCR), primarily caused by Fusarium species, is a significant soil-borne disease that severely threatens global wheat production and food security. To identify myxobacterial resources with biocontrol potential against FCR, we screened 81 myxobacterial strains using dual-culture assays and evaluated their efficacy through greenhouse and field experiments. Three strains—HM-E, KT23, and KE15—were identified for their potent broad-spectrum activity against the dominant pathogens F. pseudograminearum, F. graminearum, and F. culmorum, achieving mycelial inhibition rates ranging from 82.01 to 94.84%. Their cell-free filtrates significantly inhibited hyphal growth while inducing spore lysis and suppressing germination. These strains employed a range of inhibitory mechanisms complementary to their conventional predatory activity. Greenhouse trials demonstrated that both fermentation broths and solid agents provided control efficacies of 52.94–88.24% against single and complex infections, consistently outperforming the chemical fungicide Tebuconazole (40.75–59.15%). Furthermore, myxobacterial treatments significantly promoted wheat growth, as evidenced by increased plant height, primary root length, and fresh weight. In field trials, the biocontrol efficacy reached 61.60–74.67% at the flowering stage and 57.95–71.53% at the grain-filling stage. Compared to the pathogen-only control (5,860.00 kg/ha), myxobacterial treatments increased grain yield by 13.71–27.82%. Based on morphological and multigene phylogenetic analyses, strains KT23 and KE15 were identified as Myxococcus fulvus, while HM-E was identified as Cystobacter fuscus. This study identifies C. fuscus HM-E and M. fulvus KT23 and KE15 as robust biocontrol resources with dual functions in disease suppression and growth promotion, providing a novel technical framework and microbial candidates for the sustainable management of wheat Fusarium Crown Rot.