RNAi knockdown of heat shock proteins affects thermotolerance of Ephestia kuehniella (Lepidoptera: Pyralidae)

The Mediterranean flour moth, Ephestia kueheniella is one of the most severe pests in stores worldwide. Like many other stored product pests, chemical pesticides are often used to control this insect. As many of these chemicals negatively impact non-target species, safer alternative methods are needed. Temperature is one of the environmentally friendly control methods that can achieve the desired levels of control. Still, the insects' induction of cold and heat tolerance can decrease control efficacy. In the current study, we first investigated the susceptibility of all developmental stages of the Mediterranean flour moth to extreme heat and cold temperatures. Exposure to ۴۴ °C for ۸۰ minutes or -۱۵ °C for ۳۰ minutes caused significant mortalities in all developmental stages. Exposure to mild low or high temperatures induced cold or heat tolerance and reduced the mortality rate. Quantitative RT-PCR confirmed that heat or cold-inducible tolerance was accompanied by up-regulation of transcripts for two heat shock proteins, HSP۷۰ and HSP۹۰; transcript levels of HSP۷۰ and HSP۹۰ increased ۳.۸ and ۴.۳-fold after pre-exposure to ۳۵°C for ۳۰ min and ۳.۸ and ۳.۳-fold after pre-exposure to ۱۰°C for ۳۰ min compared to controls, respectively. Suppression of HSP۷۰ and HSP۹۰ transcripts using RNA interference (RNAi) significantly reduced heat and cold tolerance, indicating that these two proteins play a crucial role in the induction of heat and cold tolerance in the Mediterranean flour moth.

کلیدواژه ها:

HSP۷۰ ، HSP۹۰ ، RNA interference ، Integrated pest management