Molecular cloning, expression profiling and functional characterization of three small heat shock protein genes in Sogatella furcifera reveals their roles in heat tolerance

The white-backed planthopper (WBPH), Sogatella furcifera (Horváth), is a destructive rice pest in Asia that causes significant economic losses in China's major rice-growing regions. Small heat shock proteins (shsps) play a vital role in temperature adaptation across a wide range of organisms. To evaluate the impact of shsp on high-temperature tolerance in Sogatella furcifera , we cloned the complete cDNA sequences of SfHsp21.9 , SfHsp22.4 , and SfHsp23.1 , and analyzed their expression under high-temperature conditions. Additionally, we confirmed their functionality using RNA interference (RNAi). Overall, the results indicated that the SfHsp21.9, SfHsp22.4, and SfHsp23.1 genes encode 192, 199, and 192 amino acids, respectively. Their molecular weights were 21.69, 22.47, and 21.81 ​kDa, respectively. Phylogenetic analysis revealed the relative conservation of three shsp genes in the WBPH. Real-time quantitative PCR (qPCR) showed that all three shsp genes were significantly upregulated after 1 ​h of high-temperature exposure, with their expression levels increasing progressively as the temperature increased. RNAi experiments demonstrated that the injection of double-stranded RNAs (dsRNAs) targeting these three shsp genes effectively inhibited their expression at the transcriptional level and significantly reduced the survival rate of the WBPH. After high-temperature treatment, silencing these proteins leads to an increased mortality rate. Accordingly, our study contributes to a better understanding of the heat tolerance mechanisms in this species and provides valuable insights for the integrated pest management of rice planthoppers in eastern Asia. • Phylogenetic analysis revealed the relative conservation of three sHsp genes in the WBPH. • The expression of the SfHsp21.9 and SfHsp23.1 genes was significantly upregulated after heat shock. • RNAi bioassays revealed that the three Hsps play key roles in the heat resistance of the WBPH.