# Developmental and Reproductive Impacts of Arsenophonus Symbiont on the Population of Nilaparvata lugens

## TL;DR

This study shows that the Arsenophonus bacterium slows the development and reproduction of rice pests, especially when they feed on transgenic rice.

## Contribution

The study reveals how Arsenophonus affects pest biology on transgenic rice, offering new insights for sustainable pest control.

## Key findings

- Arsenophonus infection increased development time and reduced reproductive capacity in N. lugens.
- Infected females had smaller reproductive organs and lower expression of key reproduction-related genes.
- Arsenophonus altered lipid metabolism and other metabolic pathways, impacting pest fitness.

## Abstract

The Brown Planthopper (Nilaparvata lugens) is a major pest of rice that significantly impacts crop yields. This research explores how the bacterium Arsenophonus, a common microorganism in insects, influences the development and reproduction of N. lugens. The research compared the development and reproductive traits of N. lugens on two rice varieties: the transgenic variety KF30-14 and the non-transgenic Minghui 86. The results showed that Arsenophonus infection decreased the development of N. lugens, particularly when fed on the transgenic rice. Infected insects exhibited slower development and produced fewer offspring. Additionally, the infection altered the size of their reproductive organs and impacted important genes related to development and reproduction. These findings suggest that Arsenophonus can reduce the insect’s ability to reproduce, particularly on transgenic rice, potentially helping manage this insect in rice farming. This research highlights the complex relationship between insects’ microbial partners and their food sources. Understanding these interactions could lead to more effective and environmentally friendly insect control strategies in agriculture.

The Brown Planthopper, Nilaparvata lugens (Stål.) (Hemiptera: Delphinidae), is one of the most destructive pests of rice. Its reproductive and developmental traits are influenced by various environmental and biological factors including endosymbiotic microorganisms. Arsenophonus, a widespread endosymbiotic bacterium of insects, can affect host fitness and metabolic processes. This study investigates the role of Arsenophonus in modulating the developmental and reproductive traits of N. lugens fed on transgenic cry30Fa1 rice (KF30-14) and its parent variety Minghui 86 (MH86). Life table analysis revealed that Arsenophonus infection (Ars+) increased the development time and reduced the reproductive capacity of N. lugens, especially those feeding on KF30-14. The first-instar nymphs in MH86 Ars+ (infected) exhibited slower development compared to MH86 Ars− (uninfected). Similarly, the third and fourth-instar nymphs in KF30-14 Ars+ exhibited prolonged development time compared to KF30-14 Ars−. In addition, KF30-14 Ars+ females had significantly reduced reproductive capacity, smaller ovarian tubules and lower relative expression levels of reproduction-related genes including Trehalose transporter (Tret), Vitellogenin (Vg) and Cytochrome P450 hydroxylase (cyp314a1), while Juvenile hormone acid methyltransferase (JHAMT) expression was upregulated. RNA sequencing and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis revealed significant enrichment of genes involved in lipid, amino acid, and vitamin metabolisms, with Long-chain acyl-CoA synthetase implicated as a key regulator of lipid metabolism and reproductive fitness. These results highlight the complex interactions between endosymbionts, host plants and pest biology, offering a solid foundation for sustainable approaches to control N. lugens in rice production systems.