A novel anti-dipteran strain: Unusual Cry toxin genes in a highly dynamic plasmid environment.

emerged as a major bioinsecticide on the global market. It offers a valuable alternative to chemical products classically utilized to control pest insects. Despite the efficiency of several strains and products available on the market, the scientific community is always on the lookout for novel toxins that can replace or supplement the existing products. In this study, H3, a novel B. thuringiensis strain showing mosquitocidal activity, was isolated from Lebanese soil and characterized at an in vivo, genomic and proteomic levels. H3 parasporal crystal is toxic on its own but displays an unusual killing profile with a higher LC50 than the reference serovar israelensis crystal proteins. In addition, H3 has a different toxicity order: it is more toxic to and than to Whole genome sequencing and crystal analysis revealed that H3 can produce eleven novel Cry proteins, eight of which are assembled in genes with an organization, where is a potential Cry4-type crystallization domain. Moreover, pH3-180, the toxin-carrying plasmid, holds a wide repertoire of mobile genetic elements that amount to 22% of its size., including novel insertion sequences and class II transposable elements Two other large plasmids present in H3 carry genetic determinants for the production of many interesting molecules - such as chitinase, cellulase and bacitracin - that may add up to H3 bioactive properties. This study therefore reports a novel mosquitocidal strain with unusual Cry toxin genes in a rich mobile DNA environment. , a soil entomopathogenic bacteria, is at the base of many sustainable eco-friendly bio-insecticides. Hence stems the need to continually characterize insecticidal toxins. H3 is an anti-dipteran strain, isolated from Lebanese soil, whose parasporal crystal contains eleven novel Cry toxins and no Cyt toxins. In addition to its individual activity, H3 showed potential as a co-formulant with classic commercialized products, to delay the emergence of resistance and to shorten the time required for killing. On a genomic level, H3 holds three large plasmids, one of which carries the toxin-coding genes, with four occurrences of the distinct organization. Moreover, this plasmid is extremely rich in mobile genetic elements, unlike its two co-residents. This highlights the important underlying evolutionary traits between toxin-carrying plasmids and the adaptation of a strain to its environment and insect host spectrum.