García Matías, Ortego Félix, Hernández-Crespo Pedro, Farinós Gema P, Castañera Pedro
Department of Environmental Biology, Centro de Investigaciones Biológicas, CSIC, Madrid, Spain.
Pest Manag Sci. 2015 Dec;71(12):1631-9. doi: 10.1002/ps.3971. Epub 2015 Jan 30.
The low efficacy of MON810 maize against Mythimna unipuncta represents a scenario of non-compliance with the 'high-dose' strategy, raising concerns about potential resistance development and outbreaks of this secondary pest. The present study offers insight into the different components related to resistance in a laboratory-selected MON810-resistant (MR) strain of M. unipuncta.
The resistance in the MR strain is autosomal and inherited as a partially dominant trait. We have found a lack of fitness costs in this strain for essential life history traits, reproductive potential and most of the population growth parameters analysed, the only exception being an increment in the mean generation time. Larvae of the MR strain reared on Bacillus thuringiensis (Bt) maize took longer to develop, presented a high adult cumulative emergence time and had lower growth rate than those reared on non-Bt maize, suggesting the existence of incomplete resistance. Feeding preference assays reveal a low discrimination between Bt and conventional maize.
Both resistant and heterozygous larvae of M. unipuncta survive the Cry1Ab toxin expressed on Bt maize, with a weak fitness cost for the homozygous larvae, indicating the potential risk of field-evolved resistance and its relevance to resistance monitoring. © 2015 Society of Chemical Industry.
MON810玉米对一点谷螟防治效果不佳，这不符合“高剂量”策略，引发了对该次生害虫潜在抗性发展及爆发的担忧。本研究深入探讨了实验室选育的一点谷螟MON810抗性（MR）品系中与抗性相关的不同组成部分。
MR品系的抗性为常染色体遗传，呈部分显性性状。我们发现该品系在基本生活史特征、繁殖潜力以及所分析的大多数种群增长参数方面不存在适合度代价，唯一的例外是平均世代时间有所增加。在苏云金芽孢杆菌（Bt）玉米上饲养的MR品系幼虫发育时间更长，成虫累计羽化时间长，且生长速率低于在非Bt玉米上饲养的幼虫，这表明存在不完全抗性。取食偏好试验表明，Bt玉米和常规玉米之间的区分度较低。
一点谷螟的抗性幼虫和杂合幼虫均可在Bt玉米上表达的Cry1Ab毒素中存活，纯合幼虫的适合度代价较小，这表明田间进化抗性存在潜在风险及其与抗性监测的相关性。© 2015化学工业协会。
