Function of Vitellogenin receptor gene in reproductive regulation of Zeugodacus cucurbitae (Coquillett) after short-term high-temperature treatment

Abstract

Climate change has increased the frequency of extreme heat events. Zeugodacus cucurbitae (Coquillett) is an important tropical pest that typically changes its reproductive strategies in response to extremely high temperatures. Newly emerged adults of three consecutive generations (F1, F2, and F3) of Z. cucurbitae (Coquillett) were exposed to 25°C, 33°C, 37°C, 41°C, and 45°C treatments for 1 h to clarify the effects of short-term high temperatures on its reproduction. The influence of these temperatures on reproduction was evaluated using indicators, such as egg number. Newly emerged adults were exposed to 25°C and 45°C treatments for 1 h, and the expression of Vitellogenin receptor (VgR) gene in females was interfered with siRNA, and silencing efficiency of RNAi was evaluated. Results showed that short-term high temperatures, except for F1 treated at 45°C for 1 h to stimulate oviposition, exert a general adverse effect on the reproduction of Z. cucurbitae (Coquillett). All F3 died after the 45°C treatment for 1 h. Silencing of the VgR gene resulted in the significant downregulation of VgR gene expression at both 24 and 72 h. The egg number, oviposition days, and hatchability of eggs were significantly lower than those of other treatment groups after interference, and the inhibition effect of egg number was the most evident, with a decrease of 88.4% and 95.2% at 25°C and 45°C, respectively, compared with that of the Control Check (CK). Ovarian development speed and diameter were also significantly lower than those of other treatment groups after the interference. The results of this study can provide a theoretical reference for the integrated control of Z. cucurbitae (Coquillett) during high-temperature seasons.

The ZcVgR gene is involved in the regulation of reproduction and lifespan in female Zeugodacus cucurbitae (Coquillett) mediated by short-term high temperature

“…Following a previous study (Lian et al, 2022a), siRNA for the ZcVgR gene was synthesised by Tsingke Biotech (Shanghai, China) with a positive strand of 5' CGAUGUCGAGGAUGUGUUATT 3' and an antisense strand of 5' UAACACAUCCUCGACAUCGTT 3'.…”

“…The relative expression of the ZcVgR gene was measured in newly emerged female Z. cucurbitae treated at 33°C, 37°C, 41°C and 45°C for 1 h. It was concluded that short-term high temperature treatment drove the downregulation of the ZcVgR gene, and the expression of the ZcVgR gene increased progressively with increasing number of days, and it increased rapidly from 5 d to reach the peak at 7 d (Lian et al, 2022b). To investigate the function of the ZcVgR gene in female Z. cucurbitae mediated by short-term high temperature, newly emerged females were treated at 45°C for 1 h, and then injected with siRNA to silence the ZcVgR gene at 5 d of age, and the egg number and lifespan of females were signi cantly reduced (Lian et al, 2022a), suggesting that the ZcVgR gene is involved in the regulation of reproduction and lifespan in females mediated by short-term high temperature. However, how does the ZcVgR gene regulate short-term high temperature-mediated reproduction and lifespan in female Z. cucurbitae?…”

The vitellogenin receptor gene is involved in lifespan regulation of Zeugodacus cucurbitae (Coquillett) after short-term high-temperature treatment

“…VgR, in concert with Vg, is involved in a range of physiological and behavioral activities in insects ( Lian et al, 2022b ). Our previous research showed that the reproductive ability and ovarian development rate of Z. cucurbitae were significantly decreased after interference with the VgR gene of 5-day-old females ( Lian et al, 2022a ). In addition, we found that interference with the VgR gene impacted the lifespan of female Z. cucurbitae ; however, the mechanism of that effect was unclear.…”

Knockdown of the ecdysone receptor disrupts development and causes mortality in the melon fly, Zeugodacus cucurbitae

“…In Z. cucurbitae, the injection or ingestion of gene-specific dsRNAs successfully suppressed the target gene expression in larvae and adults, leading to developmental defects and mortality. For instance, the knockdown of vitellogenin genes significantly reduced its fecundity and caused ovarian defects (Chen et al, 2022;Li et al, 2021;Lian et al, 2022), while the knockdown of imaginal disc growth factors (IDGF6) caused wing malformation, the knockdown of the tyrosineprotein kinase-like tok gene (Tpk-Tok) caused a black and distorted body and major larval mortality and the knockdown of Argonaute1 (Ago1) and Gawky affected ovarian development and pigmentation (Ahmad et al, 2021(Ahmad et al, , 2023aJamil et al, 2022). To further develop efficient RNAi-based pest control strategies for Z. cucurbitae achieving very high larval mortality (the most destructive stage), it is important to test new gene candidates, which could later be targeted in cosilencing approaches (Ahmad et al, 2023b).…”