Plant Quarantine Technology Center, Animal and Plant Quarantine Agency, Gimcheon, 39660, Korea.
Department of Plant Medicals, Andong National University, Andong, 36729, Korea.
Sci Rep. 2024 Nov 9;14(1):27334. doi: 10.1038/s41598-024-79082-y.
The fall armyworm (FAW), Spodoptera frugiperda is a cold-sensitive species that overwinters in temperate climates without diapause. Overwintering in insects involves rapid cold hardening (RCH), supported by trehalose (TRE), which serves as an intermediate between glycogen (GLY) and glucose (GLU). However, both GLU and TRE help maintain homeostasis under stress. TRE is hydrolyzed by the enzyme trehalase (Treh) into GLU. This study retrieved Sf-Treh1a, Sf-Treh1b, and Sf-Treh2 from the FAW transcriptome analysis. RNA interference (RNAi) targeting these three Treh genes resulted in significant downregulation of mRNA levels and altered survival rates in RNAi-treated FAW larvae following RCH treatment. High-pressure liquid chromatography (HPLC) quantification of TRE and GLU in treated groups suggests that GLU is an essential component of the hemolymph for survival adaptation to cold conditions in S. frugiperda. This study reveals limited cold adaptability of FAW, as evidenced by lower glucose concentration levels. We found that FAW requires alternative molecules, in conjunction with glucose and trehalose for freeze tolerance and survivability. Our study aims to discover the molecular mechanisms that contribute to freeze tolerance in FAW by exploring the roles of trehalose, glucose, and glycogen.
秋粘虫（FAW），Spodoptera frugiperda 是一种对冷敏感的物种，在没有滞育的情况下在温带地区越冬。昆虫的越冬包括快速冷驯化（RCH），由海藻糖（TRE）支持，海藻糖在糖原（GLY）和葡萄糖（GLU）之间充当中间物。然而，GLU 和 TRE 都有助于在压力下维持体内平衡。TRE 被海藻糖酶（Treh）水解成 GLU。本研究从 FAW 转录组分析中检索到 Sf-Treh1a、Sf-Treh1b 和 Sf-Treh2。针对这三个 Treh 基因的 RNA 干扰（RNAi）导致 RCH 处理后 RNAi 处理的 FAW 幼虫的 mRNA 水平显著下调和生存率改变。经处理组 TRE 和 GLU 的高压液相色谱（HPLC）定量表明，GLU 是 S. frugiperda 血液适应低温条件的生存的必需成分。这项研究表明，FAW 的耐寒性有限，因为葡萄糖浓度水平较低。我们发现，FAW 需要替代分子，与葡萄糖和海藻糖一起用于耐冻结和存活。我们的研究旨在通过探索海藻糖、葡萄糖和糖原的作用，发现导致 FAW 耐冻结的分子机制。
