| Article ID | Journal | Published Year | Pages | File Type |
|---|---|---|---|---|
| 4557624 | Journal of Invertebrate Pathology | 2015 | 10 Pages |
•Bona fide cadherin cDNA sequence of Plutella xylostella was cloned and analyzed.•The Cry1Ac-susceptible and -resistant cadherin protein sequences are not different.•Midgut cadherin transcript levels are similar in susceptible and resistant strains.•Cadherin gene silencing shows no effect on larval susceptibility to Cry1Ac toxin.•No genetic linkage was detected between cadherin gene and Bt Cry1Ac resistance.
The Gram-positive bacterium Bacillus thuringiensis (Bt) produces Cry toxins that have been used to control important agricultural pests. Evolution of resistance in target pests threatens the effectiveness of these toxins when used either in sprayed biopesticides or in Bt transgenic crops. Although alterations of the midgut cadherin-like receptor can lead to Bt Cry toxin resistance in many insects, whether the cadherin gene is involved in Cry1Ac resistance of Plutella xylostella (L.) remains unclear. Here, we present experimental evidence that resistance to Cry1Ac or Bt var. kurstaki (Btk) in P. xylostella is not due to alterations of the cadherin gene. The bona fide P. xylostella cadherin cDNA sequence was cloned and analyzed, and comparisons of the cadherin cDNA sequence among susceptible and resistant P. xylostella strains confirmed that Cry1Ac resistance was independent of mutations in this gene. In addition, real-time quantitative PCR (qPCR) indicated that cadherin transcript levels did not significantly differ among susceptible and resistant P. xylostella strains. RNA interference (RNAi)-mediated suppression of cadherin gene expression did not affect larval susceptibility to Cry1Ac toxin. Furthermore, genetic linkage assays using four cadherin gDNA allelic biomarkers confirmed that the cadherin gene is not linked to resistance against Cry1Ac in P. xylostella. Taken together, our findings demonstrate that Cry1Ac resistance of P. xylostella is independent of the cadherin gene.
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