Gene expression profiles of heat shock proteins 70 and 90 from empoasca onukii (Hemiptera: Cicadellidae) in response to temperature stress

Abstract

Empoasca onukii Matsuda is a worldwide pest that causes great economic loss in tea growing areas and is significantly affected by temperatures. Heat shock protein (Hsp) genes are important in insects' response to temperature stress. In this study, two full-length Hsp genes, Eohsp90 and Eohsp70, were cloned from E. onukii using rapid amplification of complementary DNA ends. The open reading frames of Eohsp90 and Eohsp70 were 2,172 bp and 2,016 bp in length, respectively. Their deduced amino acid sequences of Eohsp90 and Eohsp70 showed high homology with other species. Subsequently, the transcriptional expression of Eohsp90 and Eohsp70 in E. onukii adults exposed to various temperatures (-5, 0, 10, 15, 20, 25, 30, 35, 38, 41 and 44°C) for 1 h, and at extreme temperatures (0°C and 41°C) for various time duration (0, 20, 40, 60, 80, 100, and 120 min) were investigated via real-time quantitative polymerase chain reaction. The relative expression levels of both Eohsp90 and Eohsp70 in E. onukii adults were upregulated as the temperature rises or falls over time, except in the -5°C or 44°C temperature groups. Moreover, the expression level in the temperature elevated groups was higher than that of the lower temperature groups. In addition, the Eohsp70 generally demonstrated a higher transcriptional level than Eohsp90, and both genes had a higher expression profile in female adults compared with the males. The expression profiles indicated that Eohsp90 and Eohsp70 may play important roles in E. onukii adult responses to ecologically relevant environmental temperature threat.