Characterization of heat shock protein 90, 70 and their transcriptional expression patterns on high temperature in adult of Grapholita molesta (Busck).

Grapholita molesta (Busck) is a worldwide insect pest damaging stone and pome fruits. High temperature can significantly affect insect survival, development and fecundity. Heat shock protein (Hsp) genes were speculated to possess a pivotal function in response to high temperature stress. In this study, two full-length Hsp genes, Gmhsp90 and Gmhsp70, were cloned from G. molesta using rapid amplification of complementary DNA ends (RACE). The open reading frames of Gmhsp90 and Gmhsp70 obtained were 2 148 bp and 1 998 bp in length, respectively. Their deduced amino acids showed high homology to Hsp genes of other species. Subsequently, the transcriptional expression of Gmhsp90 and Gmhsp70 in G. molesta adults exposed at various temperatures (26, 29, 32, 35, 38, 41 and 44°C) for 1 h and at 41°C for various time duration (0, 15, 30, 45, 60, 75, 90 and 105 min) were investigated via real time quantitative polymerase chain reaction (qPCR). The relative expression levels of Gmhsp90 and Gmhsp70 in G. molesta adults were both up-regulated with the rise of temperature and time duration. In addition, the Gmhsp70 usually showed a higher transcription accumulation than Gmhsp90. Interestingly, Gmhsp90 and Gmhsp70 in female adults could be induced much earlier than that in males, and the effective induction temperature in females was also lower than that in males. The distinct expression profiles of Gmhsp90 and Gmhsp70 indicated that Gmhsp90 and Gmhsp70 may play important roles in G. molesta adults responding to a thermal threat, and there is difference on induction between sexes.