Characterization of Ionotropic Receptor Gene EonuIR25a in the Tea Green Leafhopper, Empoasca onukii Matsuda

Abstract

Ionotropic receptors (IRs) play a central role in detecting chemosensory information from the environment and guiding insect behaviors and are potential target genes for pest control. Empoasca onukii Matsuda is a major pest of the tea plant Camellia sinensis (L.) O. Ktze, and seriously influences tea yields and quality. In this study, the ionotropic receptor gene EnouIR25a in E. onukii was cloned, and the expression pattern of EnouIR25a was detected in various tissues. Behavioral responses of E. onukii to volatile compounds emitted by tea plants were determined using olfactometer bioassay and field trials. To further explore the function of EnouIR25a in olfactory recognition of compounds, RNA interference (RNAi) of EnouIR25a was carried out by ingestion of in vitro synthesized dsRNAs. The coding sequence (CDS) length of EnouIR25a was 1266 bp and it encoded a 48.87 kD protein. EnouIR25a was enriched in the antennae of E. onukii. E. onukii was more significantly attracted by 1-phenylethanol at a concentration of 100 µL/mL. Feeding with dsEonuIR25a significantly downregulated the expression level of EonuIR25a, after 3 h of treatment, which disturbed the behavioral responses of E. onukii to 1-phenylethanol at a concentration of 100 µL/mL. The response rate of E. onukii to 1-phenylethanol was significantly decreased after dsEonuIR25a treatment for 12 h. In summary, the ionotropic receptor gene EnouIR25a was highly expressed in the antennae of E. onukii and was involved in olfactory recognition of the tea plant volatile 1-phenylethanol. The present study may help us to use the ionotropic receptor gene as a target for the behavioral manipulation of E. onukii in the future.

Mutagenesis of Odorant Receptor Coreceptor Orco Reveals the Odorant-Detected Behavior of the Predator Eupeodes corollae

“…Interestingly, EcorOrco −/− mutants of both male and female hoverflies still exhibited responses to several of the tested chemicals, such as 3-methyl-2-butenal and 2,3-butanedione (Figure 2C,D). This suggests that, in addition to the OR-dependent olfactory pathways, there may be other pathways in hoverflies, such as the ionotropic receptors (IRs), which play a role in recognizing these compounds [22]. This is consistent with studies in D. melanogaster, where single sensillum recording (SSR) recording showed that 2,3-butanedione not only activates ORs, but also elicits electrophysiological responses from IRs [23].…”

RNAi-Mediated Interference with EonuGR1 Affects the Recognition of Phenylacetaldehyde by Empoasca onukii Matsuda (Hemiptera: Cicadellidae)

“…PxylGR34 is a relevant receptor for the detection of brassinolide and 24-epibrassinolide in P. xylostella [37]. Previous studies showed that 63%, 70%, and 67% of E. onukii adults responded to phenylacetaldehyde at concentrations of 0.1, 10, and 100 µL/mL and were more attracted to phenylacetaldehyde at concentrations of 10 and 100 µL/mL [42]. After interference with EonuGR1 for 3 h, the responses to acetophenone decreased insignificantly, with no significant differences from the controls, and some decrease for 1-phenylethanol at 10 µL/mL, but no significant differences at other concentrations in E. onukii.…”

“…In our previous research, olfactory responses of E. onukii to 1-phenylethanol, acetophenone, and phenylacetaldehyde were studied [42], and the results showed that the E. onukii adults were more attracted to volatiles, including phenylacetaldehyde at a concentration of 10 µL/mL, acetophenone as well as 1-phenylethanol at a concentration of 100 µL/mL. A Y-tube olfactometer was used to determine the behavioral changes of E. onukii in response to tea plant volatile compounds after interference with EonuGR1.…”

An Antennae-Enriched Odorant-Binding Protein EonuOBP43 Mediate the Behavioral Response of the Tea Green Leafhopper, Empoasca onukii Matsuda to the Host and Nonhost Volatiles

“…RNAi referred to Zhang et al (2023) method. 34 EonuOBP43 was silenced by feeding dsEonuOBP43. The purified products, dsEo-nuOBP43, were thawed on ice, and the concentration was diluted to 1000 ng/μL.…”