Spodoptera frugiperda is a highly destructive pest that has become a global problem due to its robust reproductive and migratory capabilities.  Transient receptor potential (TRP) channels, which constitute a vast ion channel family, play pivotal roles in sensing the external environment and maintaining internal homeostasis in insects.  TRP channels have been widely investigated for their critical roles in regulating various insect behaviors in recent years.  In this study, we identified 15 TRP gene loci encoding 26 transcripts in the genome of S. frugiperda and analyzed their expression profiles at different developmental stages.  The results revealed that S. frugiperda possesses four TRPC genes, six TRPA genes, one TRPM gene, two TRPV genes, one TRPN gene, and one TRPML gene, while a canonical TRPP is absent.  Moreover, the SfruTRPA1 was functionally characterized using the Xenopus oocyte expression system.  The results showed that SfruTRPA1 is activated by temperature increases from 20 to 45°C, and there is no significant desensitization after repeated stimuli within the same temperature range.  Additionally, SfruTRPA1 is activated by certain natural chemicals, including allyl isothiocyanate (AITC) and cinnamaldehyde (CA).  These findings provide valuable insights to the TRP genes in S. frugiperda.

Chemicals that modify pest behavior are developed to reduce crop damage by altering pest behavior, using specific genes within the olfactory system as molecular targets. The identification of these molecular targets in Bactrocera dorsalis, also known as the functional study of key olfactory genes, relies on CRISPR/Cas9-mediated gene knockout techniques. However, these techniques face limitations when applied to lethal genes. Transgenic technology offers a solution since it enables precise manipulation of gene expression in specific tissues or during certain developmental stages. Consequently, this study developed a piggyBac-mediated transgenic system in B. dorsalis to investigate reporter gene expression in olfactory organs, and assessed the olfactory behavior and antennal electrophysiological responses in transgenic lines. The goal was to assess the potential of this approach for future research on olfactory gene function. A universally expressed housekeeping gene from the BdorActin family was identified using the developmental transcriptome dataset. Its candidate promoter region (BdorActinA3a-1^P-2k) was then cloned into the piggyBac plasmid. We subsequently established two stable transgenic lines with specific TTAA insertion sites on chromosomes 4 and 5, consistent with the characteristics of piggyBac transposition. The transgenic strains exhibited essentially normal survival, with hatchability and adult lifespan unaffected, although there were slight reductions in the emergence rate and oviposition capacity. The fluorescent reporter has been successfully expressed in olfactory-related organs, such as the antennae, proboscis, maxillary palp, legs, external genitalia, and brain. The antennal electrophysiological responses to representative chemicals in the transgenic lines were consistent with those of the wild type. However, some olfactory-related behaviors, such as pheromone response and mating, were significantly affected in the transgenic lines. These findings suggest that our system could potentially be applied in future olfactory research, such as driving the expression of exogenous elements that are effective in olfactory organs. However, caution is advised regarding its impact when applied to some olfactory-related behavioral phenotypes.

Transient receptor potential (TRP) channels are a class of ion channel proteins that are closely related to thermosensation in insects. They are involved in detecting the ambient temperature and play vital roles in insect survival and reproduction. In this study, we identified and cloned two variants of the TRPA subfamily gene in Myzus persicae, MperTRPA1(A) and MperTRPA1(B), and analyzed their tissue expression by real-time quantitative PCR. Subsequently, these two variants of MperTRPA1 were expressed in the Xenopus oocyte system, and their functions were investigated using the two-electrode voltage clamp technique. The role of the MperTRPA1 gene in temperature adaptation of M. persicae was further determined by RNA interference and a behavioral choice assay to evaluate responses to temperature gradients. The results showed that the MperTRPA1 gene is widely expressed in tissues of M. persicae, with MperTRPA1(A) highly expressed in the mouthparts and MperTRPA1(B) mainly expressed in the antennae. The functional characterization results showed that both variants of MperTRPA1 could be activated and were not desensitized when the temperature increased from 20 to 45°C. The current value and thermal sensitivity (coefficient Q10 value) of MperTRPA1(B) were significantly higher than those of MperTRPA1(A). When the MperTRPA1 gene was knocked down, the behavioral preference of M. persicae for the optimal temperature was reduced and tended to be at a higher temperature, showing a shift in the temperature adaptation range compared to both the wild type and dsGFP-treated M. persicae. In summary, our results elucidated the molecular mechanism of adaptive temperature perception in M. persicae mediated by the thermal sensor MperTRPA1.