在Helicoverpa zea的转基因Bt作物中,实验室产生的和现场产生的抗性之间的不匹配
Andrew W Legan1, Carson W Allan1, Zoe N Jensen1
1Department of Entomology, University of Arizona, Tucson, AZ 85721.
概括
玉米耳 (Helicoverpa zea) 对Bacillus thuringiensis (Bt) Cry1Ac毒素的野外发生的耐药性是复杂的. 基因组分析显示,在一些耐药种群中,素基因拷贝数量增加,但其他遗传因素也会有所贡献.
科学领域:
- 农业昆虫学 农业昆虫学
- 遗传学和基因组学 遗传学和基因组学
- 虫害管理 虫害管理 虫害管理
背景情况:
- 转基因作物表达Bacillus thuringiensis (Bt) 晶体 (Cry) 蛋白质对于控制农业害虫至关重要.
- 美国主要的农作物害虫Helicoverpa zea已经对Bt Cry1Ac蛋白质产生了耐药性,这对害虫管理构成了重大挑战.
- 在H. zea中现场进化的耐药性的遗传基础在很大程度上是未知的,与实验室选择的耐药性机制形成鲜明对比.
研究的目的:
- 为了研究Helicoverpa zea. 在自然种群中对Cry1Ac现场进化的耐药性的基因组基础.
- 确定导致关键农业害虫实用耐药性的遗传因素.
- 了解实验室识别和现场观察到的阻力机制之间的差异.
主要方法:
- 对来自美国南部七个州的17个地点的937个Helicoverpa zea个体进行基因组分析.
- 查20个候选基因的突变,这些基因以前与Bt耐药性或易感性有关.
- 评估基因群中的拷贝数变异,特别关注素基因.
主要成果:
- 在所有研究的H. zea种群中观察到广泛的基因流动的证据.
- 现场进化的耐药性与20个先前涉及的候选基因的突变无关.
- 增加九素基因群的拷贝数与耐药性有关,但这种放大也在敏感样本中发现,并且在所有耐药样本中并不普遍存在.
结论:
- 在H. zea中现场进化的Cry1Ac耐药性是遗传复杂的,不仅仅是通过实验室研究中发现的单基因突变来解释的.
- 素基因放大可能有助于耐药性,但不是唯一或一致的机制,这表明其他遗传因素也参与其中.
- 实验室衍生和现场发展的耐药性之间的差异凸显了管理Helicoverpa zea种群的挑战,并强调了需要综合性害虫管理策略的需要.
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