# A Thermo-Sensitive Molecular Switch: Pyrexia-1 Dynamically Regulates Low-Temperature Adaptation in Chrysoperla nipponensis

## TL;DR

This study identifies a temperature-sensitive gene, Pyrexia-1, that helps green lacewings survive cold temperatures by regulating metabolic changes.

## Contribution

The study reveals Pyrexia-1 as a novel molecular switch linking temperature sensing to cold tolerance in insects.

## Key findings

- Knockdown of Pyrexia-1 lowers the supercooling and freezing points in C. nipponensis, improving cold survival.
- Pyrexia-1 inhibition increases trehalose accumulation and activates Hsp70, aiding freeze resistance.
- Pyrexia-1 acts as a negative regulator of cold tolerance by modulating metabolic pathways.

## Abstract

Cold tolerance of natural enemy insects is a critical determinant of their overwintering survival and efficacy in biological control. The green lacewing (Chrysoperla nipponensis) is an important natural enemy insect that overwinters as adults in nature; however, its high overwintering mortality severely limits its effective application in spring. To investigate the molecular mechanisms underlying low-temperature adaptation, this study focuses on the temperature-sensitive Transient Receptor Potential (TRP) channels and their roles in the cold tolerance of C. nipponensis. The TRPA subfamily gene, Pyrexia-1, was identified and found to be significantly downregulated upon cold exposure. A functional analysis indicates RNAi-mediated knockdown of Pyrexia-1 significantly lowered both the supercooling point and the freezing point of C. nipponensis adults, enhancing their survival rate at −10 °C. These results indicate Pyrexia-1 as a negative regulator of cold tolerance. Further mechanistic investigation revealed that inhibition of Pyrexia-1 function specifically down regulates the expression of trehalase (TRE1) genes, resulting in a marked accumulation of the cryoprotectant trehalose in adults. This metabolic adjustment was accompanied by the upregulation of heat shock protein Hsp70. Overall, these findings establish Pyrexia-1 as a critical molecular switch linking temperature-sensing signals to the metabolic pathways governing freeze resistance, thereby orchestrating the systemic cold adaptation in C. nipponensis. This discovery provides novel insights into the molecular basis of insect low-temperature adaptation and suggests a potential strategy for enhancing the overwintering capacity of natural enemy insects by targeting this regulatory node.