Genomic characterization and biocontrol potential of the endophytic Purpureocillium lilacinum PL6 and Beauveria bassiana YC-1 against southern corn rust

Southern corn rust (SCR), caused by Puccinia polysora , is a destructive foliar disease that threatens maize production worldwide. Excessive dependence on synthetic chemical fungicides has led to an urgent demand for eco-friendly biocontrol alternatives based on beneficial microorganisms. Here, we characterized two maize-derived endophytic fungi, Purpureocillium lilacinum PL6 and Beauveria bassiana YC-1, using morphological observation, molecular phylogenetic identification, whole-genome sequencing, laboratory bioassays, and insect pathogenicity tests. Illumina sequencing generated draft genomes of 36.68 Mb for PL6 and 33.05 Mb for YC-1. dbCAN3 identified 187 and 137 carbohydrate-active enzyme-encoding genes, respectively, and antiSMASH predicted 34 and 32 secondary metabolite biosynthesis-related gene clusters, including PKS-, NRPS- and terpene-associated clusters. Root-drench inoculation with either strain restricted the development of SCR under the controlled conditions used in this study. At 24 days post-inoculation, the disease incidence remained below 4% in the PL6 treatment group and was approximately 21% in the YC-1 treatment, compared with nearly 48% in the untreated control group. The area under the disease progress curve (AUDPC) decreased from 87.12 in the control to 20.92 following the YC-1 treatment and 10.58 following the PL6 treatment, corresponding to reductions of 76.0% and 87.9%, respectively. In the fifth-instar Spodoptera frugiperda larvae bioassays, 10-day survival was approximately 73% with YC-1 and 83% with PL6 corresponding to mortality of approximately 27% and 17%, respectively. These findings demonstrate that PL6 and YC-1 have potential as genome-reported, dual-purpose fungal resources for the integrated management of foliar rust disease and lepidopteran pests.