Single nucleotide deletion of cqm1 gene results in the development of resistance to Bacillus sphaericus in Culex quinquefasciatus
Autor: | Qing-yun Guo, Zhiming Yuan, Dasheng Zheng, Xiaomin Hu, Jianping Yan, Quanxin Cai |
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Rok vydání: | 2013 |
Předmět: |
Physiology
Culex Bacterial Toxins Bacillus Genes Insect medicine.disease_cause Bacillus sphaericus Microbiology Insecticide Resistance Complementary DNA parasitic diseases medicine Animals Pest Control Biological Escherichia coli Gene Sequence Deletion biology Toxin fungi alpha-Glucosidases Sequence Analysis DNA biology.organism_classification Culex quinquefasciatus genomic DNA Larva Insect Science Host-Pathogen Interactions Female |
Zdroj: | Journal of Insect Physiology. 59:967-973 |
ISSN: | 0022-1910 |
DOI: | 10.1016/j.jinsphys.2013.07.002 |
Popis: | The entomopathogen Bacillus sphaericus is one of the most effective biolarvicides used to control the Culex species of mosquito. The appearance of resistance in mosquitoes to this bacterium, however, remains a threat to its continuous use in integrated mosquito control programs. Previous work showed that the resistance to B. sphaericus in Culex colonies was associated with the absence of the 60-kDa binary toxin receptor (Cpm1/Cqm1), an alpha-glucosidase present in the larval midgut microvilli. In this work, we studied the molecular basis of the resistance developed by Culex quinquefasciatus to B. sphaericus C3-41. The cqm1 genes were cloned from susceptible (CqSL) and resistant (CqRL/C3-41) colonies, respectively. The sequence of the cDNA and genomic DNA derived from CqRL/C3-41 colony differed from that of CqSL one by a one-nucleotide deletion which resulted in a premature stop codon, leading to production of a truncated protein. Recombinant Cqm1S from the CqSL colony expressed in Escherichia coli specifically bound to the Bin toxin and had α-glucosidase activity, whereas the Cqm1R from the CqRL/C3-41 colony, with a deletion of three quarters of the receptor’s C-terminal lost its α-glucosidase activity and could not bind to the binary toxin. Immunoblotting experiments showed that Cqm1 was undetectable in CqRL/C3-41 larvae, although the gene was correctly transcribed. Thus, the cqm1R represents a new allele in C. quinquefasciatus that confers resistance to B. sphaericus. |
Databáze: | OpenAIRE |
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