title: The midgut cadherin-like gene is not associated with resistance to Bacillus thuringiensis toxin Cry1Ac in Plutella xylostella (L.).
abstract: 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.
authors.affiliation: Department of Plant Protection, Institute of Vegetables and Flowers, Chinese Academy of Agricultural Sciences, Beijing 100081, China. Electronic address: zjguo1988@163.com.
authors.forename: Zhaojiang
authors.initials: Z
authors.lastname: Guo
authors.affiliation: Department of Plant Protection, Institute of Vegetables and Flowers, Chinese Academy of Agricultural Sciences, Beijing 100081, China. Electronic address: kangshi0718@163.com.
authors.forename: Shi
authors.initials: S
authors.lastname: Kang
authors.affiliation: Department of Plant Protection, Institute of Vegetables and Flowers, Chinese Academy of Agricultural Sciences, Beijing 100081, China. Electronic address: zhuxun99@gmail.com.
authors.forename: Xun
authors.initials: X
authors.lastname: Zhu
authors.affiliation: Department of Plant Protection, Institute of Vegetables and Flowers, Chinese Academy of Agricultural Sciences, Beijing 100081, China. Electronic address: wuqingjun@caas.cn.
authors.forename: Qingjun
authors.initials: Q
authors.lastname: Wu
authors.affiliation: Department of Plant Protection, Institute of Vegetables and Flowers, Chinese Academy of Agricultural Sciences, Beijing 100081, China. Electronic address: wangshaoli@caas.cn.
authors.forename: Shaoli
authors.initials: S
authors.lastname: Wang
authors.affiliation: Department of Plant Protection, Institute of Vegetables and Flowers, Chinese Academy of Agricultural Sciences, Beijing 100081, China. Electronic address: xiewen@caas.cn.
authors.forename: Wen
authors.initials: W
authors.lastname: Xie
authors.affiliation: Department of Plant Protection, Institute of Vegetables and Flowers, Chinese Academy of Agricultural Sciences, Beijing 100081, China. Electronic address: zhangyoujun@caas.cn.
authors.forename: Youjun
authors.initials: Y
authors.lastname: Zhang
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001413:Bacillus thuringiensis; D000083722:Bacillus thuringiensis Toxins; D001426:Bacterial Proteins / Q000494:pharmacology*; D015820:Cadherins / Q000737:chemistry / Q000235:genetics*; D003001:Cloning, Molecular; D004731:Endotoxins / Q000494:pharmacology*; D020868:Gene Silencing; D006460:Hemolysin Proteins / Q000494:pharmacology*; D054884:Host-Pathogen Interactions; D019476:Insect Proteins / Q000737:chemistry / Q000235:genetics*; D007305:Insecticide Resistance / Q000235:genetics; D008969:Molecular Sequence Data; D009036:Moths / Q000187:drug effects* / Q000235:genetics; D010802:Phylogeny; D016415:Sequence Alignment; D017422:Sequence Analysis, DNA; D020539:Sequence Analysis, Protein
chemical_list: D000083722:Bacillus thuringiensis Toxins; D001426:Bacterial Proteins; D015820:Cadherins; D004731:Endotoxins; D006460:Hemolysin Proteins; D019476:Insect Proteins; C030956:insecticidal crystal protein, Bacillus Thuringiensis
keywords: Bacillus thuringiensis; Cadherin-like gene; Cry toxin receptor; Cry1Ac resistance; Plutella xylostella