Transcripts of the nicotinic acetylcholine receptor subunit gene Pxylα6 with premature stop codons are associated with spinosad resistance in diamondback moth, Plutella xylostella

The cDNA sequence of the α6 nicotinic acetylcholine receptor subunit of diamondback moth (Plutella xylostella) was cloned and sequenced. Transcripts were similar between the spinosad susceptible G88 and Wapio strains. Transcripts from the spinosad resistant Pearl-Sel strain contained premature stop codons, and most transcripts have not been previously reported. None of these truncated transcripts were seen in the spinosad susceptible strains. Proteins made from these transcripts would likely have no, or greatly altered, receptor function. An F2 backcross and spinosad bioassay showed that spinosad bioassay survivors produced truncated transcripts and those that died produced both full length and truncated transcripts. Thus it appears that spinosad resistance in diamondback moth is due to a mutation(s) that results in no functional Pxylα6 being produced.