Nguyen Tam T, Collins Patrick J, Ebert Paul R
School of Biological Sciences, University of Queensland, St. Lucia, Queensland, Australia; Faculty of Biology, Hanoi National University of Education, Hanoi, Vietnam.
Department of Agriculture, Fisheries and Forestry, Ecosciences Precinct, Brisbane, Queensland, Australia.
PLoS One. 2015 Apr 17;10(4):e0124335. doi: 10.1371/journal.pone.0124335. eCollection 2015.
Sitophilus oryzae (Linnaeus) is a major pest of stored grain across Southeast Asia and is of increasing concern in other regions due to the advent of strong resistance to phosphine, the fumigant used to protect stored grain from pest insects. We investigated the inheritance of genes controlling resistance to phosphine in a strongly resistant S. oryzae strain (NNSO7525) collected in Australia and find that the trait is autosomally inherited and incompletely recessive with a degree of dominance of -0.66. The strongly resistant strain has an LC50 52 times greater than a susceptible reference strain (LS2) and 9 times greater than a weakly resistant strain (QSO335). Analysis of F2 and backcross progeny indicates that two or more genes are responsible for strong resistance, and that one of these genes, designated So_rph1, not only contributes to strong resistance, but is also responsible for the weak resistance phenotype of strain QSO335. These results demonstrate that the genetic mechanism of phosphine resistance in S. oryzae is similar to that of other stored product insect pests. A unique observation is that a subset of the progeny of an F1 backcross generation are more strongly resistant to phosphine than the parental strongly resistant strain, which may be caused by multiple alleles of one of the resistance genes.
米象（Linnaeus）是东南亚地区储存谷物的主要害虫，由于对用于保护储存谷物免受害虫侵害的熏蒸剂磷化氢产生了强烈抗性，在其他地区也日益受到关注。我们研究了从澳大利亚采集的对磷化氢具有强抗性的米象菌株（NNSO7525）中控制磷化氢抗性的基因遗传情况，发现该性状是常染色体遗传，呈不完全隐性，显性度为-0.66。强抗性菌株的半数致死浓度（LC50）比敏感对照菌株（LS2）高52倍，比弱抗性菌株（QSO335）高9倍。对F2和回交后代的分析表明，两个或更多基因导致了强抗性，其中一个名为So_rph1的基因不仅导致强抗性，还导致了菌株QSO335的弱抗性表型。这些结果表明，米象对磷化氢的抗性遗传机制与其他仓储害虫相似。一个独特的观察结果是，F1回交世代的一部分后代对磷化氢的抗性比亲本强抗性菌株更强，这可能是由其中一个抗性基因的多个等位基因引起的。
