Isolation of new Micro RNAs from the diamondback moth (Lepidoptera: Yponomeutidae) genome by a computational method

Abstract

The diamondback moth, Plutella xylostella (L.) (Lepidoptera: Yponomeutidae) is a serious pest of crucifers, worldwide, and has developed high levels of resistance to insecticides including Bacillus thuringiensis (Bt). This serious situation requires the identification of non-chemical, alternate, futuristic pest management strategies, which might involve gene silencing. This would first require the identification of small RNAs and their targets, and later their suitable deployment. Micro RNAs (miRNAs) are a class of small RNAs directly involved in various biological functions by regulating gene expression at the post transcriptional level. Finding new miRNAs and predicting their targets from Insect genome would lead to better understanding of their diverse functions. In the present study we have identified 8 new mature miRNAs of P. xylostella and predicting their mRNA targets by computational methods. The following 4 miRNAs are reported for the first time in arthropods, viz., miR-244, miR-3529, miR-4704, and miR-7267. We have also analyzed the precursor sequences of the newly identified miRNAs, and we have predicted their secondary structure with minimum free energy index, MFEI, which ranges 0.85 to 1.24. The mRNA target predictions for novel miRNAs were carried out using the Miranda program employing the available putative gene set sequences of P. xylostella.