Using double-stranded RNA to explore the role of heat shock protein genes in heat tolerance in Bemisia tabaci (Gennadius)

Abstract

SUMMARYThe whitefly, Bemisia tabaci (Gennadius) (Homoptera: Aleyrodidae) biotype B, is one of the most destructive invasive pests of field and glasshouse crops, and has a high tolerance to heat. Our previous work found that whitefly females are more heat tolerant than males. In the present study, real-time PCR and double-stranded RNA (dsRNA) methods were used to explore the role of heat shock protein (Hsp) genes in whitefly of both sexes; this provided further evidence of the mechanism underlying the differential heat tolerance abilities of females and males. The results showed that both hsp23 and hsp70 mRNA expression levels were higher in females than in males from 37.5 to 42°C, while at the extreme temperature of 44°C the hsp70 mRNA level was higher in males than in females. There was no significant difference in hsp90 mRNA expression between females and males under heat shock conditions. Furthermore, the survival rate of females fed hsp23 or hsp70 dsRNA significantly decreased following heat shock at 44°C for 1h, but male survival rate was not significantly affected. Additionally, the survival rate of both females and males showed no significant change after they were fed with hsp90 dsRNA. Collectively, the present study shows that the optimum mRNA expression of Hsp genes in females promotes a higher survival rate under heat shock conditions; hsp23 and hsp70 play a key role for heat tolerance in females but not in males, and hsp90 shows no significant role in heat tolerance in either females or males. Further, our study indicates that feeding with dsRNA is an effective method by which to study gene function, and the simplicity of this approach opens the way for further research on gene function in different sexes and diverse groups of species.

Trade-offs between survival, longevity, and reproduction, and variation of survival tolerance in Mediterranean Bemisia tabaci after temperature stress

“…On the other hand, Chen et al (1987) found that a 2 h pre-treatment at 36°C could enhance the survival of Sarcophaga crassipalpis Macquart (Diptera: Sarcophagidae) at -10°C. Reactions to pre-treatment might have multiple physiological bases and different underlying mechanisms in different species ( Bubliy and Loeschcke 2005 ) and may include responses by stress proteins, such as heat-shock proteins ( Lü and Wan 2008 , 2011), cryoprotectants, etc. The exact reason for different levels of cold tolerance after heat exposure pre-treatment was not clear and needed further investigation to reveal the mechanism operating in Mediterranean B. tabaci.…”

Transient Receptor Potential Is Essential for High Temperature Tolerance in Invasive Bemisia tabaci Middle East Asia Minor 1 Cryptic Species

“…Furthermore, Rosenzweig et al showed that RNA interference (RNAi)-mediated knockdown of dTRPA1 caused warm avoidance defects in Drosophila larvae, suggesting that dTRPA1 was essential for thermotaxis in Drosophila [37]. In recent years, RNAi technology has been successfully applied to the study of gene silencing in whiteflies [18], [26]. Our previous work indicated that feeding with dsRNA could lead to the inhibition of target gene mRNA expression [18] because whiteflies have a cross-membrane transport mechanism.…”

“…In recent years, RNAi technology has been successfully applied to the study of gene silencing in whiteflies [18], [26]. Our previous work indicated that feeding with dsRNA could lead to the inhibition of target gene mRNA expression [18] because whiteflies have a cross-membrane transport mechanism. Thus, we used the feeding dsRNA method to identify the function of the MEAM1 BtTRP gene under high temperature conditions.…”

“…Feeding was performed using the parafilm clip nutrient solution method [18], [27]. The parafilm was pre-treated with 0.1% diethyl pyrocarbonate (DEPC) solution to remove any RNases, and then RNase-free water was used to clean the DEPC from the parafilm.…”

“…Previous studies have suggested that the ability of B. tabaci MEAM1 to resist heat may be one of the mechanisms that potentially underlies its invasive traits [15]–[17]. Lü and Wan [18] found that hsp23 and hsp70 plays a key role in heat tolerance in B. tabaci MEAM1 females. However, it remains unclear how the information of surrounding temperature transfers to the insect’s neural network and stimulates the expression of hsp23 and hsp70 to increase the heat resistance ability of B. tabaci MEAM1 adults.…”