摘要
Over-expression of the cytochrome P450 CYP6CM1 gene has been associated with imidacloprid resistance in a number of Q and B biotype Bemisia tabaci laboratory strains from distinct geographical origins worldwide. We recently demonstrated that the Q biotype version of the CYP6CM 1 protein （CYP6CMlvQ） is capable of metabolizing imida- cloprid. Here, we show that the levels of BtCYP6CMlvQ were also elevated in laboratory- resistant strains and field-derived populations, with variable imidacloprid resistance levels, collected in Crete. High levels of CYP6CMlvQ transcripts were also determined in survivors of a heterogeneous field population, after exposure to discriminating imidacloprid dosage. Using peptide antibody-based detection assays, we demonstrated that in line with transcriptional data, the CYP6CMlvQ protein levels were higher in imidacloprid-resistant insects, which further implicates the gene as the causal factor of resistance. Finally, assess- ment of the cross-metabolism potential of CYP6CMlvQ against additional neonicotinoid molecules used for B. tabaci control revealed that clothianidin and thiacloprid, but not acetamiprid or thiamethoxam, are metabolized by the recombinant enzyme in vitro.
Over-expression of the cytochrome P450 CYP6CM1 gene has been associated with imidacloprid resistance in a number of Q and B biotype Bemisia tabaci laboratory strains from distinct geographical origins worldwide. We recently demonstrated that the Q biotype version of the CYP6CM 1 protein （CYP6CMlvQ） is capable of metabolizing imida- cloprid. Here, we show that the levels of BtCYP6CMlvQ were also elevated in laboratory- resistant strains and field-derived populations, with variable imidacloprid resistance levels, collected in Crete. High levels of CYP6CMlvQ transcripts were also determined in survivors of a heterogeneous field population, after exposure to discriminating imidacloprid dosage. Using peptide antibody-based detection assays, we demonstrated that in line with transcriptional data, the CYP6CMlvQ protein levels were higher in imidacloprid-resistant insects, which further implicates the gene as the causal factor of resistance. Finally, assess- ment of the cross-metabolism potential of CYP6CMlvQ against additional neonicotinoid molecules used for B. tabaci control revealed that clothianidin and thiacloprid, but not acetamiprid or thiamethoxam, are metabolized by the recombinant enzyme in vitro.
