Cloning and Expression of Heat Shock Protein 90 Gene from the Diapausing Larvae of the Rice Stem Borer, Chilo Suppressalis (Lepidoptera: Pyralidae) exposed to Temperature Stress

The rice stem borer, Chilo suppressalis Walker, is an economically important pest distributed in rice producing regions of China To understand its molecular adaptation, the authors cloned the cDNA sequence of CcsHsp90 which is essential for dealing with many environmental stresses in all organisms and measured the mRNA expression in the diapausing larvae exposed to temperature stress The results showed that CcsHsp90 (GenBank accession no FJ866608) is potentially encoded to 312 amino acids with calculated molecular weight of 35 59KDa and the theoretical isoeletric point of 4 72 The deduced amino acid sequence of CcsHsp90 is displayed over 80% of the degree of conservation to other Lepidopteran insects The relative mRNA expression levels of CcsHsp90 in the diapausing larvae which were exposed to different temperatures from 28 degrees C (CK) to -14 degrees C with a gradient of 7 degrees C for 4h increased first and decreased later and peaked at 0 C Then the larvae were exposed to 0 degrees C for 0 similar to 8h, the change of the levels was the same as the above and peaked at 4h treatment Therefore, it could be concluded that 0 degrees C for 4h treatment might induce the maximal expression of CcsHsp90 in the diapausing larvae of the rice stem borer