Zhu Xun, Yang Yanjv, Wu Qingjun, Wang Shaoli, Xie Wen, Guo Zhaojiang, Kang Shi, Xia Jixing, Zhang Youjun
Department of Plant Protection, Institute of Vegetables and Flowers, Chinese Academy of Agricultural Sciences, Beijing, China.
Pest Manag Sci. 2016 Feb;72(2):289-97. doi: 10.1002/ps.3991. Epub 2015 Mar 13.
Resistance to Bacillus thuringiensis (Bt) formulations in insects may be associated with fitness costs. A lack of costs enables resistance alleles to persist, which may contribute to the rapid development and spread of resistance in populations.
To assess the fitness costs associated with Bt Cry1Ac resistance in Plutella xylostella, life tables were constructed for a near-isogenic resistant strain (NIL-R) and a susceptible strain in this study. No fitness costs associated with Cry1Ac resistance in NIL-R were detected, based on the duration of egg and larval stages, the survival of eggs and larvae, adult longevity, fecundity, net reproductive rate, gross reproduction rate, finite rate of increase and mean generation time. Based on log dose-probit lines, resistance in NIL-R is incompletely recessive and results from a single, autosomal, recessive locus; the degree of dominance was estimated to be -0.74 and -0.71 for F1 (resistant ♀ × susceptible ♂) and F1 ' (susceptible ♀ × resistant ♂) progeny respectively.
Assessment of near-isogenic Cry1Ac-resistant and Cry1Ac-susceptible strains of P. xylostella indicated that resistance is not accompanied with fitness costs, and that resistance is incompletely recessive. These findings should be useful in managing the development of Bt Cry1Ac resistance.
昆虫对苏云金芽孢杆菌（Bt）制剂的抗性可能与适合度代价相关。缺乏适合度代价会使抗性等位基因持续存在，这可能导致种群中抗性的快速发展和传播。
为评估小菜蛾对Bt Cry1Ac抗性相关的适合度代价，本研究构建了近等基因抗性品系（NIL-R）和敏感品系的生命表。基于卵期和幼虫期的持续时间、卵和幼虫的存活率、成虫寿命、繁殖力、净生殖率、总生殖率、有限增长率和平均世代时间，未检测到NIL-R中与Cry1Ac抗性相关的适合度代价。基于对数剂量-概率线，NIL-R中的抗性为不完全隐性，由单个常染色体隐性位点导致；F1（抗性♀×敏感♂）和F1'（敏感♀×抗性♂）后代的显性度估计分别为-0.74和-0.71。
对小菜蛾近等基因Cry1Ac抗性和Cry1Ac敏感品系的评估表明，抗性不伴有适合度代价，且抗性为不完全隐性。这些发现对于管理Bt Cry1Ac抗性的发展应是有用的。
