Chemical signaling plays a critical role in the behavior and physiology of many animals. Female insects, as many other animals, release sex pheromones to attract males for mating. The evolutionary and ecological success of insects therefore hinges on their ability to precisely mediate (including initiation and termination) pheromone biosynthesis. Pheromone biosynthesis activating neuropeptide (PBAN) acts directly on pheromone glands to regulate sex pheromone production using Ca²⁺ and cyclic-AMP as secondary messengers in the majority of species. However, the molecular mechanism downstream of the secondary messengers has not yet been elucidated in heliothine species. The present study shows that calcineurin, protein kinase A (PKA) and acetyl-coA carboxylase (ACC) are key components involved in PBAN-induced sex pheromone biosynthesis in Helicoverpa armigera using PBAN-dependent phosphoproteomics in combination with transcriptomics. RNAi-mediated knockdown and inhibitor assay demonstrated that calcineurin A is required for PBAN-induced ACC activation and sex pheromone production. Calcineurin-dependent phosphoproteomics and in vitro calcineurin phosphorylation assay further revealed that calcineurin regulated ACC activity by dephosphorylating ser84 and ser92. In addition, PKA-dependent phosphoproteomics and activity analysis revealed that PKA reduces the activity of AMP-activated protein kinase (AMPK), a negative regulator of ACC by phosphorylating the conserved ser92. Taken together, our findings indicate that calcineurin acts as the downstream signal of PBAN/G-protein receptor/Ca²⁺ to activate ACC through dephosphorylation while inactivating AMPK via PKA to reduce ACC phosphorylation, thus facilitating calcineurin activation of ACC.

RNA interference (RNAi)-based biopesticides are novel biologic products, developed using RNAi principles. They are engineered to target genes of agricultural diseases, insects, and weeds, interfering with their target gene expression so as to hinder their growth and alleviate their damaging effects on crops. RNAi-based biopesticides are broadly classified into resistant plant-based plant-incorporated protectants (PIPs) and non-plant-incorporated protectants. PIP RNAi-based biopesticides are novel biopesticides that combine the advantages of RNAi and resistant transgenic crops. Such RNAi-based biopesticides are developed through nuclear or plastid transformation to breed resistant plants, i.e., dsRNA-expressing transgenic plants. The dsRNA of target genes is expressed in the plant cell, with pest and disease control being achieved through plant-target organism interactions. Here, we review the action mechanism and strategies of RNAi for pest management, the development of RNAi-based transgenic plant, and the current status and advantages of deploying these products for pest control, as well as the future research directions and problems in production and commercialization. Overall, this study aims to elucidate the current development status of RNAi-based biopesticides and provide guidelines for future research.

DNA methylation has been proposed to play critical roles in caste fate and behavioral plasticity in bumblebees, however, there is little information on its regulatory mechanisms. Here, we identified six important genes mediating the modification of DNA methylation and determined their expression patterns in the bumblebee Bombus terrestris. There is a complete functional DNA methylation system, including four DNA methyltransferases (DNMT1a, DNMT1b, DNMT2, and DNMT3), a DNA demethylase (Ten-eleven translocation), and a methyl-CpG-binding domain protein in B. terrestris. Most of these genes were highly expressed in fat bodies and gonads but lowly expressed in antennae and brains of bumblebee adults. Besides, these genes exhibited caste-specific expression patterns in bumblebees, with higher transcription levels in queens than workers and drones. Whereas their expression levels showed no remarkable difference in queenright and queenless workers. These results suggested potential roles of DNA methylation-related genes in caste differentiation in bumblebees.

Summary: Sugar deficiency is the persistent challenge for plants during development. Trehalose‐6‐phosphate (T6P) is recognized as a key regulator in balancing plant sugar homeostasis. However, the underlying mechanisms by which sugar starvation limits plant development are unclear. Here, a basic helix–loop–helix (bHLH) transcription factor (OsbHLH111) was named starvation‐associated growth inhibitor 1 (OsSGI1) and the focus is on the sugar shortage of rice. The transcript and protein levels of OsSGI1 were markedly increased during sugar starvation. The knockout mutants sgi1‐1/2/3 exhibited increased grain size and promoted seed germination and vegetative growth, which were opposite to those of overexpression lines. The direct binding of OsSGI1 to sucrose non‐fermenting‐1 (SNF1)‐related protein kinase 1a (OsSnRK1a) was enhanced during sugar shortage. Subsequently, OsSnRK1a‐dependent phosphorylation of OsSGI1 enhanced the direct binding to the E‐box of trehalose 6‐phosphate phosphatase 7 (OsTPP7) promoter, thus rose the transcription inhibition on OsTPP7, then elevated trehalose 6‐phosphate (Tre6P) content but decreased sucrose content. Meanwhile, OsSnRK1a degraded phosphorylated‐OsSGI1 by proteasome pathway to prevent the cumulative toxicity of OsSGI1. Overall, we established the OsSGI1‐OsTPP7‐Tre6P loop with OsSnRK1a as center and OsSGI1 as forward, which is activated by sugar starvation to regulate sugar homeostasis and thus inhibits rice growth.