# The ZcVg3 Gene Regulates the Reproduction and Lifespan of Female Zeugodacus cucurbitae (Coquillett) Mediated by Short-Term High Temperatures

## TL;DR

A gene called ZcVg3 is crucial for the reproduction of a pest insect under short-term high temperatures, and silencing it reduces their reproduction and lifespan.

## Contribution

The study identifies the ZcVg3 gene's role in enhancing reproduction of Zeugodacus cucurbitae under high temperatures and its potential as an RNAi target for pest control.

## Key findings

- Silencing the ZcVg3 gene reduced fecundity, spawning days, ovarian development, and lifespan of female pests.
- ZcVg3 gene suppression led to upregulation of ZcVg1 and ZcVg2 genes and altered ZcVgR gene expression.
- RNAi targeting ZcVg3 shows potential for controlling pest populations under high-temperature conditions.

## Abstract

Exposure to short-term high temperatures of 45 °C can enhance the development and reproduction of Zeugodacus cucurbitae (Coquillett). In this study, the function of the ZcVg3 gene in reproduction was studied by interfering with its expression via the injection of siRNA. The silencing of the ZcVg3 gene could affect the expression of other related genes. It also resulted in a significant reduction in egg production, spawning days, ovarian development and lifespan. The results suggest that the ZcVg3 gene plays a crucial role in pest reproduction under short-term high temperatures.

Zeugodacus cucurbitae (Coquillett) is a significant pest affecting fruit and vegetables in tropical and subtropical regions, and its development and reproduction are enhanced after exposure to short-term high-temperature stress at 45 °C. Vitellogenin (Vg) is an essential precursor of yolk protein formation in eggs and plays a vital role in the ovarian development of insects. Interfering with the Z. cucurbitae vitellogenin receptor (ZcVgR) gene in short-term high-temperature conditions decreases the fecundity of female adults, while the transcription level of the ZcVg3 gene increases. To elucidate the reproductive function of the ZcVg3 gene and the synergistic relationship among the ZcVgs genes under short-term high temperatures, this study injected siRNA to interfere with the ZcVg3 gene after subjecting Z. cucurbitae to a 1 h treatment at 45 °C and 25 °C. The expression of the ZcVg3 gene was suppressed, leading to the upregulation of the ZcVg1 and ZcVg2 genes, and the expression of the ZcVgR gene was initially decreased and then increased. Silencing the ZcVg3 gene after a 1 h treatment at 45 °C resulted in a reduction of approximately 84.7% and 75.9% in the fecundity and spawning days of female adults compared to the control. The development rate of their ovaries and the ovarian diameter significantly decreased, and their lifespan was reduced by 71%. The ZcVg3 gene plays a crucial role in the reproduction of Z. cucurbitae in short-term high-temperature conditions. The results of this study provide potential targets for the development of RNAi-based techniques for the control of Z. cucurbitae.