State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, China.
Beijing Institutes of Life Sciences, Chinese Academy of Sciences, Beijing 100101, China.
Toxins (Basel). 2022 Jun 2;14(6):388. doi: 10.3390/toxins14060388.
The “high-dose/refuge” strategy is expected to work most effectively when resistance is inherited as a functionally recessive trait and the fitness costs associated with resistance are present. In the present study, a laboratory selected Mythimna separata strain that have evolved >634.5-fold resistance to Vip3Aa19 was used to determine the mode of inheritance. To determine if fitness costs were associated with the resistance, life history parameters (larva stage, pupa stage, pupal weight, adult longevity and fecundity) of resistant (RR), -susceptible (SS) and heterozygous (R♂S♀ and R♀S♂) strains on nontoxic diet were assayed. The LC50 values of R♀S♂ were significantly higher than that of R♂S♀ (254.58 μg/g vs. 14.75 μg/g), suggesting that maternal effects or sex linkage were present. The effective dominance h of F1 offspring decreased as concentration increased, suggesting the resistance was functionally dominant at low concentration and recessive at high concentration. The analysis of observed and expected mortality of the progeny from a backcross suggested that more than one locus is involved in conferring Vip3Aa19 resistance. The results showed that significant differences in many life history traits were observed among the four insect genotypes. In short, resistance to Vip3Aa19 in M. separata was inherited as maternal and multigene and the resistance in the strain was associated with significant fitness costs. The results described here provide useful information for understanding resistance evolution and for developing resistance management strategies.
“高剂量/避难所”策略预计在抗性作为功能隐性性状遗传且存在与抗性相关的适应代价时最为有效。在本研究中，使用了一种已进化出对 Vip3Aa19 抗性>634.5 倍的实验室选择的粘虫（Mythimna separata）菌株来确定遗传方式。为了确定抗性是否与适应代价相关，在非毒性饮食上测定了抗性（RR）、敏感（SS）和杂合（R♂S♀和 R♀S♂）菌株的生活史参数（幼虫期、蛹期、蛹重、成虫寿命和繁殖力）。R♀S♂的 LC50 值显著高于 R♂S♀（254.58μg/g 对 14.75μg/g），表明存在母体效应或性连锁。随着浓度的增加，F1 后代的有效显性 h 值降低，表明在低浓度时抗性为功能显性，而在高浓度时为隐性。对回交后代的观察和预期死亡率的分析表明，有一个以上的基因座参与赋予 Vip3Aa19 抗性。结果表明，在这四个昆虫基因型之间观察到许多生活史特征存在显著差异。简而言之，粘虫对 Vip3Aa19 的抗性是母体和多基因遗传的，该抗性与显著的适应代价相关。这里描述的结果为理解抗性进化和制定抗性管理策略提供了有用的信息。
