Culex quinquefasciatus carrying Wolbachia is less susceptible to entomopathogenic bacteria
Leonardo M. Díaz-Nieto, María Florencia Gil, Jorge Nicolás Lazarte, M. Alejandra Perotti, Corina M. Berón
Abstract
Abstract In an attempt to evaluate the susceptibility of the mosquito Culex quinquefasciatus to bacterial agents, a population naturally infected with a Wolbachia pipientis w PipSJ native strain was tested against the action of three bacterial mosquitocides, Bacillus thuringiensis subsp. israelensis , Bacillus wiedmannii biovar thuringiensis and Lysinibacillus sphaericus. Tests were carried out on mosquito larvae with and without Wolbachia (controls). Cx. quinquefasciatus naturally infected with the native w PipSJ strain proved to be more resistant to the pathogenic action of the three mosquitocidal bacterial strains. Additionally, w PipSJ was fully characterised using metagenome-assembled genomics, PCR–RFLP (PCR-Restriction Fragment Length Polymorphism) and MLST (MultiLocus Sequence Typing) analyses. This Wolbachia strain w PipSJ belongs to haplotype I, group w Pip-III and supergroup B, clustering with other mosquito w Pip strains, such as w Pip PEL, w Pip JHB, w Pip Mol, and w AlbB; showing the southernmost distribution in America. The cytoplasmic incompatibility phenotype of this strain was revealed via crosses between wildtype ( Wolbachia + ) and antibiotic treated mosquito populations. The results of the tests with the bacterial agents suggest that Cx. quinquefasciatus naturally infected with w PipSJ is less susceptible to the pathogenic action of mosquitocidal bacterial strains when compared with the antibiotic-treated mosquito isoline, and is more susceptible to B. thuringiensis subsp. israelensis than to the other two mosquitocidal agents.