Small heat shock proteins (sHSPs) function as molecular chaperones in multiple physiological processes and are active during thermal stress. sHSP expression is controlled by heat shock transcription factor (HSF); however, few studies have been conducted on HSF in agricultural pests. Liriomyza trifolii is an introduced insect pest of horticultural and vegetable crops in China. In this study, the master regulator, HSF1, was cloned and characterized from L. trifolii, and the expression levels of HSF1 and five sHSPs were studied during heat stress. HSF1 expression in L. trifolii generally decreased with rising temperatures, whereas expression of the five sHSPs showed an increasing trend that correlated with elevated temperatures. All five sHSPs and HSF1 showed an upward trend in expression with exposure to 40 ℃ without a recovery period. When a recovery period was incorporated after thermal stress, the expression patterns of HSF1 and sHSPs in L. trifolii exposed to 40 °C was significantly lower than expression with no recovery period. To elucidate potential interactions between HSF1 and sHSPs, double-stranded RNA was synthesized to knock down HSF1 in L. trifolii by RNA interference. The knockdown of HSF1 by RNAi decreased the survival rate and expression of HSP19.5, HSP20.8, and HSP21.3 during high-temperature stress. This study expands our understanding of HSF1-regulated gene expression in L. trifolii exposed to heat stress.

小热休克蛋白 (sHSP) 在多种生理过程中充当分子伴侣，并在热应激期间活跃。 sHSP表达受热休克转录因子 (HSF) 控制；然而，对于农业害虫中HSF的研究却很少。三叶斑潜蝇是我国园艺和蔬菜作物的外来害虫。本研究从三叶草中克隆并鉴定了主调节因子HSF1 ，并研究了热应激期间HSF1和5个sHSP的表达水平。 L. trifolii中的HSF1表达通常随着温度升高而降低，而 5 个sHSP的表达则显示出与升高相关的增加趋势。所有5个sHSP和HSF1在暴露于40℃时均表现出表达上升趋势，且没有恢复期。当热应激后加入恢复期时，暴露于40℃的三叶草中HSF1和sHSP的表达模式显着低于没有恢复期的表达。为了阐明HSF1和sHSP之间的潜在相互作用，合成了双链 RNA，通过 RNA 干扰敲低三叶草中的HSF1 。通过RNAi敲低HSF1降低了高温胁迫期间HSP19.5 、 HSP20.8和HSP21.3的存活率和表达。这项研究扩展了我们对暴露于热应激的三叶草中HSF1调节基因表达的理解。