Exploring Genomic Variations and Phenotypic Traits of Chrysodeixis includens Nucleopolyhedrovirus Isolates to Improve...

Soybean production is a cornerstone of Brazilian agriculture but is heavily threatened by insect pests such as the soybean looper Chrysodeixis includens, capable of reducing yields by up to 70% if uncontrolled. Reliance on chemical insecticides is increasingly unsustainable due to environmental impacts and resistance, highlighting the need for eco-friendly alternatives. The alphabaculovirus Chrysodeixis includens nucleopolyhedrovirus (ChinNPV) is an important biocontrol agent largely used in Brazilian fields because of its host specificity and safety, although its persistence is limited by ultraviolet (UV) sensitivity. Here, we characterize two ChinNPV isolates, CNPSo-168 (C168) and Tabatinga (Tb), using genomic and phenotypic analyses. Whole-genome sequencing revealed circular dsDNA genomes of 139,290 bp (154 ORFs) for C168 and 139,131 bp (153 ORFs) for Tb, both encoding the 38 baculovirus core genes and sharing >98.9% identity with reference genomes. Comparative genomics identified 431 SNPs, including 132 nonsynonymous changes in structural, regulatory, and infection-related genes. At low concentrations, C168 showed an approximately 2-fold lower LC₅₀ than Tb (higher potency), while both achieved near-complete mortality within 8 days at higher concentrations. This greater potency at lower concentrations reinforces the efficacy-based rationale for selecting isolate C168 for biocontrol applications. Infection reduced larval growth, pupation, and adult emergence, often with developmental impairments. Despite genetic differences, both isolates were highly UV-sensitive, and formulation tests indicated that titanium dioxide combined with kaolin conferred partial protection. These results provide insights into ChinNPV diversity and support its development as a sustainable tool for soybean pest management.