Diverse genetic basis of field-evolved resistance to Bt cotton in cotton bollworm from China
Diverse genetic basis of field-evolved resistance to Bt cotton in cotton bollworm from China
复制标题
中国棉铃虫田间进化抗Bt棉抗性的多样性遗传基础
DOI：
10.1073/pnas.1200156109
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发表时间：
2012-06-26
影响因子：
11.1
通讯作者：
Wu, Yidong
中科院分区：
文献类型：
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作者：
Zhang, Haonan;Tian, Wen;Wu, Yidong
害虫抗性的进化降低了喷雾剂或转基因作物中使用的苏云金芽孢杆菌（Bt）杀虫蛋白的效力。虽然一些害虫已经在田间进化出对Bt作物的抗性，但关于田间进化出对Bt作物抗性的遗传基础的信息一直有限。特别是，在三种主要的棉花害虫中，已经确定了基于编码毒素结合钙粘蛋白蛋白的基因中的隐性突变的对Bt毒素Cry 1Ac的实验室选择性抗性，但是以前的工作还没有确定这种突变是否与对Bt棉花的田间选择性抗性相关。在中国北方用Bt棉选择的棉铃虫田间种群中，最常见的抗性等位基因具有隐性钙粘蛋白突变，包括通过实验室选择鉴定的缺失突变。然而，不像所有以前研究的钙粘蛋白抗性等位基因，一个字段选择的钙粘蛋白抗性等位基因赋予非隐性抗性。我们还检测到非隐性抗性，这是不与钙粘蛋白基因座遗传连锁。在田间选择群体中，隐性钙粘蛋白等位基因占检测到的抗性等位基因的75-84%。然而，大多数抗性等位基因发生在杂合体中，59-94%的抗性个体携带至少一个非隐性抗性等位基因。结果表明，抗性管理策略必须考虑到田间选择种群中的不同抗性等位基因，包括非隐性等位基因。
Evolution of pest resistance reduces the efficacy of insecticidal proteins from Bacillus thuringiensis (Bt) used in sprays or in transgenic crops. Although several pests have evolved resistance to Bt crops in the field, information about the genetic basis of field-evolved resistance to Bt crops has been limited. In particular, laboratory-selected resistance to Bt toxin Cry1Ac based on recessive mutations in a gene encoding a toxin-binding cadherin protein has been identified in three major cotton pests, but previous work has not determined if such mutations are associated with field-selected resistance to Bt cotton. Here we show that the most common resistance alleles in field populations of cotton bollworm, Helicoverpa armigera, selected with Bt cotton in northern China, had recessive cadherin mutations, including the deletion mutation identified via laboratory selection. However, unlike all previously studied cadherin resistance alleles, one field-selected cadherin resistance allele conferred nonrecessive resistance. We also detected nonrecessive resistance that was not genetically linked with the cadherin locus. In field-selected populations, recessive cadherin alleles accounted for 75–84% of resistance alleles detected. However, most resistance alleles occurred in heterozygotes and 59–94% of resistant individuals carried at least one nonrecessive resistance allele. The results suggest that resistance management strategies must account for diverse resistance alleles in field-selected populations, including nonrecessive alleles.