Bautista Ma Anita M, Bhandary Binny, Wijeratne Asela J, Michel Andrew P, Hoy Casey W, Mittapalli Omprakash
Department of Entomology, Ohio Agricultural Research and Development Center, The Ohio State University, Wooster, OH, USA; Present address: National Institute of Molecular Biology and Biotechnology, College of Science, University of the Philippines Diliman, Quezon City 1101, Philippines.
Pest Manag Sci. 2015 Mar;71(3):423-32. doi: 10.1002/ps.3822. Epub 2014 Jun 13.
Detoxification genes have been associated with insecticide adaptation in the diamondback moth, Plutella xylostella. The link between chemosensation genes and adaptation, however, remains unexplored. To gain a better understanding of the involvement of these genes in insecticide adaptation, the authors exposed lines of P. xylostella to either high uniform (HU) or low heterogeneous (LH) concentrations of permethrin, expecting primarily physiological or behavioral selection respectively. Initially, 454 pyrosequencing was applied, followed by an examination of expression profiles of candidate genes that responded to selection [cytochrome P450 (CYP), glutathione S-transferase (GST), carboxylesterase (CarE), chemosensory protein (CSP) and odorant-binding protein (OBP)] by quantitative PCR in the larvae. Toxicity and behavioral assays were also conducted to document the effects of the two forms of exposure.
Pyrosequencing of the P. xylostella transcriptome from adult heads and third instars produced 198,753 reads with 52,752,486 bases. Quantitative PCR revealed overexpression of CYP4M14, CYP305B1 and CSP8 in HU larvae. OBP13, however, was highest in LH. Larvae from LH and HU lines had up to five- and 752-fold resistance levels respectively, which could be due to overexpression of P450s. However, the behavioral responses of all lines to a series of permethrin concentrations did not vary significantly in any of the generations examined, in spite of the observed upregulation of CSP8 and OBP13.
Expression patterns from the target genes provide insights into behavioral and physiological responses to permethrin and suggest a new avenue of research on the role of chemosensation genes in insect adaptation to toxins.
解毒基因已与小菜蛾（Plutella xylostella）对杀虫剂的适应性相关联。然而，化学感应基因与适应性之间的联系仍未得到探索。为了更好地理解这些基因在杀虫剂适应性中的作用，作者将小菜蛾品系暴露于高均匀（HU）或低异质性（LH）浓度的氯菊酯中，分别预期主要进行生理或行为选择。最初，应用了454焦磷酸测序，随后通过定量PCR检测了对选择有反应的候选基因（细胞色素P450（CYP）、谷胱甘肽S - 转移酶（GST）、羧酸酯酶（CarE）、化学感应蛋白（CSP）和气味结合蛋白（OBP））在幼虫中的表达谱。还进行了毒性和行为测定，以记录两种暴露形式的影响。
对成虫头部和三龄幼虫的小菜蛾转录组进行焦磷酸测序，产生了198,753条读数，共52,752,486个碱基。定量PCR显示，HU幼虫中CYP4M14、CYP305B1和CSP8过表达。然而，OBP13在LH中表达最高。LH和HU品系的幼虫分别具有高达5倍和752倍的抗性水平，这可能是由于P450s的过表达。然而，尽管观察到CSP8和OBP13上调，但在所有检测世代中，所有品系对一系列氯菊酯浓度的行为反应均无显著差异。
靶基因的表达模式为对氯菊酯的行为和生理反应提供了见解，并为化学感应基因在昆虫对毒素适应性中的作用提出了新的研究途径。
