Berretta, M. F. | bioRxiv Science

bioRxiv2026

Unlocking the (Coleoptera: Tenebrionidae)-Combatting Capabilities of INTA Mo4-4 through genomic and phenotypic characterization

Bacillus thuringiensis INTA Mo4-4 was characterized phenotypically, genomically, and for insecticidal activity against Alphitobius diaperinus. Microscopy revealed rare flat rectangular parasporal crystals, and SDS-PAGE identified a ca. 67 kDa protein, similar to B. thuringiensis serovar morrisoni strain tenebrionis DSM-2803, which was proteolytically processed to a ca. 55 kDa fragment. Genomic analysis showed a 5.99 Mb genome with 99.43% completeness, clustering phylogenetically with B. cereus and B. thuringiensis. High genomic similarity was observed with B. thuringiensis svar. morrisoni BGSC 4AA1, confirmed by MLST analysis assigning it to ST-23. The genome encodes an interesting arsenal of pesticidal proteins showing significant similarity to Cry3Aa, Mpp23Aa, Xpp37Aa, Mpp5Ab, Vpb1Ad, Vpb1Ae, Vpa2Ab, Vpa2Ba, Vpa2Bb and Spp1Aa, with demonstrated toxicity against coleopteran pests. Biosynthetic gene clusters for toyoncin, fengycin, and bacillibactin were identified. Dose-response bioassays showed that INTA Mo4-4 was nearly four times more toxic to A. diaperinus larvae (LC50 136.9 {micro}g/ml) than DSM-2803 (LC50 540.5 {micro}g/ml), with the difference being statistically significant. No teratological effects were observed on Musca domestica. These findings suggest that INTA Mo4-4 is a promising candidate for the biological control of A. diaperinus.

microbiology↗

bioRxiv2020

Genomic Diversity in a Population of Spodoptera frugiperda Nucleopolyhedrovirus

Spodoptera frugiperda multiple nucleopolyhedrovirus (SfMNPV) represents a strong candidate to develop environmental-friendly pesticides against the fall armyworm (Spodoptera frugiperda), a widespread pest that poses a severe threat to different crops around the world. However, little is known regarding the genomic diversity present inside SfMNPV isolates and how it shapes the interactions between virus and host. Here, the genomic diversity present inside an isolate of SfMNPV was explored using high-throughput sequencing for the first time. We identified 704 intrahost single nucleotide variants, from which 184 are nonsynonymous mutations distributed among 82 different coding sequences. We detected several structural variants affecting SfMNPV genome, including two previously reported deletions inside the egt region. A comparative analysis between polymorphisms present in different SfMNPV isolates and our intraisolate diversity data suggests that coding regions with higher genetic diversity are associated with oral infectivity or unknown functions. In this context, through molecular evolution studies we provide evidence of diversifying selection acting on sf29, a putative collagenase which could contribute to the oral infectivity of SfMNPV. Overall, our results contribute to deepen our understanding of the coevolution between SfMNPV and the fall armyworm and will be useful to improve the applicability of this virus as a biological control agent. HighlightsO_LIWe characterized the genomic diversity within a population of SfMNPV. C_LIO_LICoding regions with higher genetics diversity are associated with oral infectivity or unknown functions. C_LIO_LISeveral structural variants contribute to the genomic diversity of SfMNPV. C_LIO_LISf29, a putative collagenase, shows signs of adaptive evolution. C_LI

microbiology↗