Identification and functional analysis of cytochrome P450 CYP346 family genes associated with phosphine resistance in Tribolium castaneum.

Resistance to phosphine fumigation has been frequently reported in insect pests of stored products and remains one of the obstacles in controlling these pests, including Tribolium castaneum. In this study, six field populations of T. castaneum were collected from different localities in China. Bioassay data showed that SZ population was strongly resistant to phosphine, followed by moderate-resistance populations WL and SF and three susceptible populations JX, YN, and ML. In addition, synergism assays showed that piperonyl butoxide significantly increased the toxicity of phosphine in resistant population SZ. Furthermore, CYP346B subfamily genes, CYP346B1, CYP346B2, and CYP346B3, were significantly overexpressed in resistant populations. Expression of CYP346B1, CYP346B2, and CYP346B3 were significantly upregulated following exposure to phosphine. RNAi assays showed that depletions on the expression levels of CYP346B1, CYP346B2, and CYP346B3 resulted in an increase of susceptibility to phosphine in T. castaneum, respectively. Our data demonstrated that CYP346B subfamily genes in T. castaneum were associated with the resistance of phosphine. Moreover, the study also increased our understanding of the molecular basis of phosphine resistance in stored pest insects.
Competing Interests: Declaration of Competing Interest The authors declare that they have no conflict of interest.
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