LAUSR

BACKGROUND Elevated temperature can directly affect the insect pest population dynamics. Many experimental studies have indicated that high temperatures affect the biological and ecological characteristics of the widely distributed crop pest Aphis gossypii, but the molecular mechanisms underlying its response to heat stress remain unstudied. Here, we used transcriptomic analysis to explore the key genes and metabolic pathways involved in the regulation of thermotolerance in A. gossypii at 29°C, 32°C, and 35°C. RESULTS The results of bioinformatics analysis show that few genes were consistently differentially expressed among the higher temperature treatments compared to 29°C, and a moderate temperature increase of 3°C can elicit gene expression changes that help A. gossypii adapt to warmer temperatures. Based on KEGG pathway enrichment analysis, we found that genes encoding four heat shock protein 70s (Hsp70s) and nine cathepsin B (CathB) proteins were significantly upregulated at 35°C compared with 32°C. Genes related to glutathione production were also highly enriched between 32°C and 29°C. Silencing of two Hsp70s (ApHsp70A1-1 and ApHsp68) and two CathBs (ApCathB01 and ApCathB02) with RNA interference using a nanocarrier-based transdermal dsRNA delivery system significantly increased sensitivity of A. gossypii to high temperatures. CONCLUSION A. gossypii is able to fine-tune its response across a range of temperatures, and Hsp70 and CathB genes are essential for adaption of A. gossypii to warmer temperatures. This article is protected by copyright. All rights reserved.