Genome-wide characterization of miRNA and siRNA pathways in the parasitoid wasp Pteromalus puparum

Authors: XIAO, SHAN - Zhejiang University Of Technology; FANG, QI - Zhejiang University Of Technology; LIU, MING-MING - Zheijiang University; ZHANG, JIAO - Zhejiang University Of Technology; WANG, BEI-BEI - Zhejian University; YAN, ZHICHAO - Zhejiang University Of Technology; WANG, FANG - Zhejiang University Of Technology; Stanley, David; YE, GONG-YIN - Zhejiang University Of Technology

Submitted to: Insects
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/10/2020
Publication Date: 3/15/2022
Citation: Xiao, S., Fang, Q., Liu, M., Zhang, J., Wang, B., Yan, Z., Wang, F., Stanley, D.W., Ye, G. 2022. Genome-wide characterization of miRNA and siRNA pathways in the parasitoid wasp Pteromalus puparum. Insects. 21(4):1106-1115. https://doi.org/10.1016/S2095-3119(20)63465-7.
DOI: https://doi.org/10.1016/S2095-3119(20)63465-7

Interpretive Summary: Application of classical insecticides has introduced severe problems in agricultural sustainability. The concept of biological control of insects is a potentially powerful alternative to classical insecticides. Biological control is based on the idea that direct application of insect-specific pathogens and parasites can reduce pest insect populations and the economic damage due to pest insects. The problem, however, is the efficiency of these organisms in biological control programs is limited by insect immune defense reactions to challenge. One approach to improving the efficiency of biocontrol agents would be to somehow disable insect immune reactions to viral, bacterial, fungal and parasitic infections. With this goal, we are investigating how insect immune reactions to infection are signaled. In this paper we report on two signal pathways that may be responsible for stimulating insect defenses to infection. This new research will be directly useful to scientists who are working to improve the efficacy of biological control methods. The ensuing improved biological control methods will benefit a wide range of agricultural producers by supporting the long-term sustainability of agriculture.

Technical Abstract: microRNAs (miRNAs) and small interfering RNAs (siRNAs) are small non-coding RNAs (ncRNAs) that trigger RNA interference (RNAi) in eukaryotic organisms. The biogenesis pathways for these ncRNAs are well established in Drosophila melanogaster, Aedes aegypti, Bombyx mori and other insects, but lacking in hymenopteran species, particularly in parasitoid wasps. Pteromalus puparum is a pupal parasitoid of butterflies. In this study, we identified and analyzed the two pathways by interrogating the P. puparum genome. Our results showed that all core genes of the two pathways are present in the genome as a single copy, except for two genes in the siRNA pathway, R2D2 (two copies) and Argonaute-2 (three). Conserved domain analysis showed structures consistent with cognate proteins in other insect species. Phylogenetic analyses of hymenopteran Dicer and Argonaute genes suggested significantly accelerated molecular evolution rates of the genes involved in siRNA pathway. Whereas we found a decelerated rate of P. puparum Dicer-2 with respect to Dicer-1, and was contrary to other hymenopteran insects. The expression analyses revealed higher mRNA levels of all miRNA pathway genes in parasitoid wasp adults. While the siRNA machinery genes were expressed in different patterns. Our information enriches the knowledge of the miRNA and siRNA pathways in parasitoid wasps.