Identification and characterization of miRNAs in an endoparasitoid wasp, Pteromalus puparum

Authors: XIAO, SHAN - Zhejiang University; WANG, BEIBEI - Zhejiang University; LI, KAI - Donghua University; XIONG, SHIJIAO - Zhejiang University; YE, XINHAI - Zhejiang University; WANG, JIALE - Zhejiang University; ZHANG, JIAO - Zhejiang University; YAN, ZHICHAO - Zhejiang University; WANG, FANG - Zhejiang University; SONG, QISHENG - University Of Missouri; Stanley, David; YE, GONGYIN - Zhejiang University; FANG, QI - Zhejiang University

Submitted to: Archives of Insect Biochemistry and Physiology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/19/2019
Publication Date: 10/6/2019
Citation: Xiao, S., Wang, B., Li, K., Xiong, S., Ye, X., Wang, J., Zhang, J., Yan, Z., Wang, F., Song, Q., Stanley, D.W., Ye, G., Fang, Q. 2019. Identification and characterization of miRNAs in an endoparasitoid wasp, Pteromalus puparum. Archives of Insect Biochemistry and Physiology. 103(2):e21633. https://doi.org/10.1002/arch.21633.
DOI: https://doi.org/10.1002/arch.21633

Interpretive Summary: Beneficial insect species provide valuable ecological services to humans. Many beneficials, such as honey bees, bumble bees, solitary bees, hoverfiies, butterflies, moths and flower beetles (in total, more than 20,000 insect species), are responsible for pollinating nearly 900 high-value food crops. Other beneficial insects are natural enemies of pest insect species. Parasitoid insects deposit their eggs into or onto other insect species, where larvae hatch from the eggs and develop to adulthood using the resources of their host insect. Many parasitoid species provide important biological control services by killing pest insects. Some parasitoid species are commercially raised and released to control pest insects. Despite their economic importance, there is very little genetic information on the beneficials. Such information is crucial to optimizing their use and economic value. This paper is one of a series of seven papers reporting on genomic analyses of the beneficial parasitoid, Pteromalus puparum. Here, we report on identification of regulatory elements that control expression of some genes. We identified 254 regulatory elements, many of which are expressed in specific development stages. The identies of these elements will enhance understanding of gene expression in beneficial parasitoid wasps. This information will be used by scientists globally to improve our understanding of parasitoid biology, which may lead to improved biological control technologies that contribute to food and nutrition sustainability generally.

Technical Abstract: MicroRNAs (miRNAs) are a form of endogenous small non-coding RNAs that regulate protein-coding gene expression at the post-transcriptional level. So far, knowledge of miRNAs in parasitoids remains rudimentary. We investigated miRNAs in Pteromalus puparum, a pupal endoparasitoid wasp with genome and transcriptome sequences completed. In this study, we constructed 8 small RNA libraries from selected developmental stages and genders: male embryos (ME), male larvae (ML), male pupae (MP), male adults (MA), mixed-sex embryos (MSE), mixed-sex larvae (MSL), mixed-sex pupae (MSP) and female adults (FA). We identified 254 mature miRNAs with 5p/3p arm features originated from 75 known and 119 novel miRNAs genes in P. puparum, 88 of which reside in 26 clusters. The miRNAs in more than half of the clusters exhibit a consistent expression pattern, indicating they were co-transcribed from a long transcript. Comparing miRNA expression in the eight libraries, we found 84 mature miRNAs were differentially expressed between embryos and larvae, 20 between larvae and pupae, and 26 between pupae and adults. We found some miRNAs were differentially expressed between sexes in embryoes (10), larvae (29), pupae (8) and adults (14). Target predictions resulted in 350 263 miRNA-mRNA interactions for 254 different mature miRNAs. These may be involved in sexual and developmental regulation by miRNAs.