Genomic signatures associated with maintenance of genome stability and venom turnover in two parasitoid wasps

Abstract

Parasitoid wasps are rapidly developing as a model for evolutionary biology. Here we present chromosomal genomes of two Anastatus wasps, A. japonicus and A. fulloi, and leverage these genomes to study two fundamental questions—genome size evolution and venom evolution. Anastatus shows a much larger genome than is known among other wasps, with unexpectedly recent bursts of LTR retrotransposons. Importantly, several genomic innovations, including Piwi gene family expansion, ubiquitous Piwi expression profiles, as well as transposable element-piRNA coevolution, have likely emerged for transposable element silencing to maintain genomic stability. Additionally, we show that the co-option evolution arose by expression shifts in the venom gland plays a dominant role in venom turnover. We also highlight the potential importance of non-venom genes that are coexpressed with venom genes during venom evolution. Our findings greatly advance the current understanding of genome size evolution and venom evolution, and these genomic resources will facilitate comparative genomics studies of insects in the future.

Genomic analyses provide insights into the genome evolution and environmental adaptation of the tobacco moth Ephestia elutella

“…A total of·2,126 strictly single-copy orthologous genes among ten Pyraloidea insects were used for identification of rapidly evolving genes and positively selected genes. We used Codeml in PAML v4.9 ( Yang, 2007 ) to detect rapidly evolving and positive selection signals on the E. elutella branch as we described previously ( Yang et al, 2021 ; Ye et al, 2022 ). Briefly, we used the branch model in Codeml to detect rapidly evolving genes on the E. elutella branch, and a likelihood ratio test (LRT) was performed compare the null model (assuming that all branches have evolved at the same rate) and the alternative model ( E. elutella branch has a different evolutionary rate).…”

Genome assembly of the ectoparasitoid wasp Theocolax elegans

“…The highly dynamic evolution of OR genes, which discriminate odour molecules derived from hosts and host habitats, is crucial for parasitoids to locate different hosts 17 – 19 . Additionally, venom proteins, which regulate host immunity, development and metabolism, likely evolve quickly and adopt novel functions in response to different host species 15 , 16 , 20 . Although the biology of T. elegans has been studied, little genetic information is presently available, which constrains its desirability and application as a biocontrol agent.…”

Identification and Comparative Expression Profiles of Candidate Olfactory Receptors in the Transcriptomes of the Important Egg Parasitoid Wasp Anastatus japonicus Ashmead (Hymenoptera: Eupelmidae)

“…In particular, Peng et al (2020) reported that Anastatus fulloi Sheng and Wang (Hymenoptera: Eupelmidae) appears to have been consistently misidentified as A. japonicus in mainland China; the extensive biological literature published under A. japonicus in China has thus been called into question [ 1 ]. Lately, Ye et al identified that 104 ORs in the genome of A. japonicus had a highly duplicated 9-exon subfamily but did not analyze the expression profiles of ORs and other olfactory genes [ 40 ].…”