An Orphan Gene Enhances Male Reproductive Success in Plutella xylostella

Genomic Analysis Reveals the Role of New Genes in Venom Regulatory Network of Parasitoid Wasps

New genes play a critical role in phenotypic diversity and evolutionary innovation. Parasitoid wasps, a highly abundant and diverse group of insects, parasitize other arthropods and exhibit remarkable evolutionary adaptations, such as evading host immune responses and exploiting host resources. However, the specific contributions of new genes to their unique traits remain poorly understood. Here, we identified 480 new genes that emerged after the Nasonia-Pteromalus divergence. Among these, 272 (56.7%) originated through DNA-mediated duplication, representing the largest proportion, followed by 77 (16.0%) derived from RNA-mediated duplication and 131 (27.3%) that arose de novo. Comparative analysis revealed that these new genes generally have shorter coding sequences and fewer exons compared to single-copy older genes conserved in the seven parasitoid wasps. These new genes are predominantly expressed in the reproductive glands and exhibit venom gland-biased expression. Notably, gene co-expression network analysis further identified that a new gene may act as a hub by interacting with older genes to regulate venom-related networks rather than directly encoding venom proteins. Together, our findings provide novel insights into the role of new genes in driving venom innovation in parasitoid wasps.

Knockout of silk fibroin genes in Plutella xylostella results in decreased fitness and performance

BACKGROUND

The ability of insects to spin silk is crucial for their survival, reproduction, and interactions with the environment. The diamondback moth (DBM), Plutella xylostella, a serious agricultural pest, relies on silk production, which influences its behavior and population dynamics.

RESULTS

This study employed CRISPR/Cas9 technology to knock out three genes, that is, silk fibroin heavy chain (PxFibH), silk fibroin light chain (PxFibL), and fibrohexamerin (PxP25), to investigate their roles in silk gland development and related biological traits. We successfully generated PxFibH, PxFibL, and PxP25 knockout mutants, which displayed defective cocoon formation and developed into naked pupae. Further analysis revealed significant alterations in silk gland structure and various biological parameters, including increased larval mortality, prolonged developmental time, reduced pupal weight, and shortened adult lifespan.

CONCLUSIONS

These findings highlight the importance of silk fibroin genes in silk production and growth development in P. xylostella, positioning them as potential targets for innovative pest control strategies. © 2025 Society of Chemical Industry.

An orphan gene is essential for efficient sperm entry into eggs in Drosophila melanogaster

While spermatogenesis has been extensively characterized in the Drosophila melanogaster model system, very little is known about the genes required for fly sperm entry into eggs. We identified a lineage-specific gene, which we named katherine johnson (kj), that is required for efficient fertilization. Males that do not express kj produce and transfer sperm that are stored normally in females, but sperm from these males enter eggs with severely reduced efficiency. Using a tagged transgenic rescue construct, we observed that the KJ protein localizes around the edge of the nucleus at various stages of spermatogenesis but is undetectable in mature sperm. These data suggest that kj exerts an effect on sperm development, the loss of which results in reduced fertilization ability. Interestingly, KJ protein lacks detectable sequence similarity to any other known protein, suggesting that kj could be a lineage-specific orphan gene. While previous bioinformatic analyses indicated that kj was restricted to the melanogaster group of Drosophila, we identified putative orthologs with conserved synteny, male-biased expression, and predicted protein features across the genus, as well as likely instances of gene loss in some lineages. Thus, kj was likely present in the Drosophila common ancestor. It is unclear whether its role in fertility had already evolved at that time or developed later in the lineage leading to D. melanogaster. Our results demonstrate a new aspect of male reproduction that has been shaped by a lineage-specific gene and provide a molecular foothold for further investigating the mechanism of sperm entry into eggs in Drosophila.

Chromosome-level genome of the brown lacewing Micromus angulatus (Stephens, 1836) (Neuroptera: Hemerobiidae)

The brown lacewing Micromus angulatus (Stephens), a member within the subfamily Microminae of the family Hemerobiidae, is a globally distributed species and an important predatory natural enemy of various agricultural and forestry crop pests. Despite its global distribution and agricultural significance, genomic resources for the development of novel pest management strategies for M. angulatus and the family Hemerobiidae remain limited. Here, we present the first high-quality chromosome-level reference genome for M. angulatus, achieved through PacBio HiFi and Hi-C technologies. The assembled genome spans 1.29 Gb, with scaffold N50 of 63.78 Mb, and complete BUSCO score of 97.00%, containing eight pseudochromosomes, demonstrates a high degree of continuity. Functional annotation identified 13,250 protein-coding genes, and repetitive sequences, which account for 83.65% of the genome, were also characterized. This comprehensive assembly offers a robust reference for in-depth research on the genetic basis of predation and adaptability in M. angulatus, supports further research into the understanding the genetic diversity within Hemerobiidae, contributing to the broader knowledge within the group and its related species.