Genome sequencing and functional annotation of Metarhizium anisopliae TNAU-MA-GDU: Insights into virulence mechanisms against Spodoptera frugiperda.

BACKGROUND: Entomopathogenic fungi such as Metarhizium anisopliae are widely recognized as promising biocontrol agents against insect pests. The fall armyworm, Spodoptera frugiperda (FAW) is a highly destructive invasive pest that poses serious threat to global food security. Identifying fungal isolates with high virulence and understanding the genomic basis of their pathogenicity are essential steps for developing sustainable biopesticides for managing fall armyworm. METHODS AND RESULTS: Seven fungal isolates, including five Beauveria bassiana and two Metarhizium species, were evaluated for their pathogenicity against second-instar FAW larvae. Among them, the isolate, M. anisopliae TNAU-MA-GDU that showed the highest larval mortality of 90 per cent and was selected for genome sequencing. Whole-genome sequencing was performed using the Illumina NovaSeq platform, yielding a draft genome of 39.75 Mb assembled into 2081 scaffolds. Gene prediction identified 13,188 coding genes, many of which are associated with host–pathogen interactions. These include enzymes involved in cuticle degradation (subtilisin proteases and chitinases), adhesion proteins (Mad1 and Mad2), and enzymes linked to secondary metabolite biosynthesis (including polyketide synthase and nonribosomal peptide synthetase). Comparative genomics revealed the presence of pathogenicity-related genes, coding for destruxin synthase, phosphoketolase, and protein kinases. CONCLUSION: The whole-genome analysis of M. anisopliae TNAU-MA-GDU provides new insights into the molecular mechanisms underlying fungal virulence against FAW. The identification of genes involved in cuticle degradation, adhesion, and secondary metabolite biosynthesis highlights the genomic potential of this isolate as a promising biocontrol agent. These findings support the development of fungal-based biopesticides for integrated pest management strategies targeting S. frugiperda.