De novo transcriptomic analysis to reveal insecticide action and detoxification-related genes of the predatory bug, Cyrtorhinus lividipennis

Abstract

The mirid bug, Cyrtorhinus lividipennis Reuter, an important predatory natural enemy of rice planthoppers, is widely distributed in rice fields. However, genetic information on C. lividipennis is lacking. Especially, limited data about mechanisms of insecticide selectivity between this piercing-sucking predator (C. lividipennis) and piercing-sucking preys (rice planthoppers), inhibits development of selective insecticides and the integration of chemical and biological control systems to control insect pests of rice. Hence, we performed de novo assembly of a transcriptome from adult and nymph whole bodies of C. lividipennis. A total of >29 million of reads were generated, and 34,752 transcripts matched known proteins. Then, the genes related to insecticide action and detoxification were manually identified, including 26 carboxylesterases (containing 2 acetylcholinesterases), 57 cytochrome P450s, 19 glutathione S-transferases, 15 nicotinic acetylcholine receptors, 3 GABA-gated ion channels, and 1 glutamate receptor. Comparisons of sequence differences in these genes between C. lividipennis and rice planthoppers, revealed that quite a lot of diversity was found among genes related to insecticide action and detoxification, while a few of these genes share much higher identities between this predator and prey. The present study provides useful information for our understanding of insecticide selectivity between rice planthoppers and the predator mirid bug.