Genome mining of insecticidal toxins and comparative genomic analysis of Lysinibacillus pinotti VCRC B653, a promising mosquito biocontrol agent with dual larvicidal and oviposition-attractant activities
摘要
Bacterial entomopathogens are widely used in mosquito control, however, the functional and genomic potential of many promising strains remains insufficiently explored. Here, we report Lysinibacillus pinotti VCRC B653, isolated from indian soil, with potent mosquitocidal activity. The spore–crystal complex showed remarkable toxicity against Culex(Cx.) quinquefasciatus, Anopheles(An.) stephensi, and Aedes(Ae.) aegypti (LC₅₀:0.014, 0.215, and 0.8 µg/mL, respectively), while remaining non-toxic to beneficial aquatic organisms. Additionally, cell-free supernatant strongly attracted for oviposition in Cx. quinquefasciatus (OAI:0.94 at 0.5% CFS). GC–MS profiling identified 22 volatile compounds, including benzeneacetic acid and 2-piperidinone, compounds previously associated with insecticidal and antimicrobial activities. Whole-genome sequencing revealed a 4.76 Mb genome (GC content: 37.1%) comprising 4948 predicted coding sequences and no plasmids. Phylogenomic analysis placed the isolate within Lysinibacillus pinotti, supported by 99.47% ANI and 96% dDDH with type strain Lysinibacillus pinotti PB211. Comparative genomics showed > 90% protein homology with PB211, alongside 511 unique genes, and diverse biosynthetic gene clusters (NRPS, PKS, and RiPPs), highlighting strain-specific features that may enhance ecological adaptability and mosquitocidal potential. Genome mining uncovered multiple insecticidal toxin families, including Tpp1Aa1/BinA, Tpp2Aa1/BinB, Cry48Aa3–Tpp49Aa4 with distinct RicinB-like lectin and P42 crystal toxin domains, and aerolysin-like β-pore-forming proteins (Mpp, Mtx, Spp). Analysis of conserved pore-forming and receptor-binding motifs provided a molecular explanation for the high larvicidal potency. Genome-based safety evaluation revealed a low probability of human pathogenicity and absence of virulence. Collectively, these findings establish L. pinotti VCRC B653 as a safe and potent mosquito-control agent and expand genomic resources to support the development of targeted and sustainable biocontrol.