Next-generation sequencing-based transcriptome analysis of Cryptolaemus montrouzieri under insecticide stress reveals resistance-relevant genes in ladybirds.

As the most efficient natural enemy of mealybugs, the ladybird Cryptolaemus montrouzieri Mulsant plays an important role in integrated pest management. We report here a profiling analysis of C. montrouzieri under insecticide stress to gain a deeper view of insecticide resistance in ladybirds. For transcriptome sequencing, more than 26 million sequencing reads were produced. These reads were assembled into 38,369 non-redundant transcripts (mean size=453 nt). 23,248 transcripts were annotated with their gene description. Using a tag-based DGE (Digital gene expression) system, over 5.7 million tags were sequenced in both the insecticide stress group and the control group, and mapped to 38,369 transcripts. We obtained 993 genes that were significantly up- or down-regulated under insecticide stress in the ladybird transcriptome. These results can contribute to in-depth research into the molecular mechanisms of resistance and enhance our current understanding of the effects of insecticides on natural enemies.