Yuting Li, Qi Zhao, Xinle Duan, Chunman Song, Maohua Chen.Transcription of Four Rhopalosiphum Padi (L.) Heat Shock Protein Genes and Their Responses to Heat Stress and Insecticide Exposure

Transcription of Four Rhopalosiphum Padi (L.) Heat Shock Protein Genes and Their Responses to Heat Stress and Insecticide Exposure.

Yuting Li, Qi Zhao, Xinle Duan, Chunman Song, Maohua Chen.

Comparative Biochemistry and Physiology

DOI:10.1016/j.cbpa.2016.12.021

Abstract: The bird cherry-oataphid, Rhopalosiphum padi(L.), a worldwide destructive pest, is more heat tolerant than other wheat aphids, and it has developed resistance to different insecticides. Heat shock proteins(HSPs) play an important role in coping with environmental stresses. To investigate Hsp transcriptional responses to heat and insecticide stress, four full-length Hsp genes from R. padi (RpHsp60, RpHsc70, RpHsp70-1, and RpHsp70-2) were cloned. Four RpHsps were expressed during all R. padi developmental stages, but at varying levels. The mRNA levels of RpHsps were increased under thermal stress and reached maximal induction at a lower temperature (36 °C) in the alate morph than in the apterous morph (37 °C or 38 °C). RpHsp expressions under heat stress suggest that RpHsp70-1 and RpHsp70-2 are inducible in both apterous andalatemorphs, RpHsc70 is only heat-inducible inapterous morph, and RpHsp60 exhibits poor sensitivity to heat stress. The pretreatment at 37 °C significantly increase both the survival rate and the RpHsps expression level of R. padi at subsequent lethal temperature. Under exposure to two sublethal concentrations (LC 10 and LC 30 ) of beta-cypermethrin, both RpHsp70-1 and RpHsp70-2 expressions were induced and reached a maximum 24 h after exposure. In contrast, expression of RpHsp60 was not induced by either sublethal concentration of beta-cypermethrin. Moreover, the responses of RpHsp70-1 and RpHsp70-2 to heat shock were more sensitive than those to beta-cypermethrin.The seresults suggest that induction of RpHsp expression is related to thermal tolerance, and that RpHsp70-1 and RpHsp70-2 are the primary genes involved in the response to both heat and pesticide stress.