Cloning of CmHSP90 Gene in Cucurbita moschata and Its Expression Analysis under Several Adversity Stresses
WANG Bin, CHEN Mindong, LIN Hui, ZHU Haisheng*, WEN Qingfang*
HSP90 (Heat shock protein 90) widely mediates stress signal transduction and plays an important role in plant stress response. In order to investigate the function of HSP90 gene in Cucurbita moschata, we isolated the ORFs (open reading frames) of two HSP90 gene from Cucurbita moschata seedling using RT-PCR method and named CmHSP90-5 and CmHSP90-6. Their sequence length were 2 357 and 2 472 bp, encoding 793 and 824 amino acids, respectively. Protein sequence analysis showed that both CmHSP90 were hydrophilic proteins with signal peptide and no transmembrane region. They all contain typical conserved domains of ATPase and subcells were located in chloroplasts and mitochondria, respectively. Homologous comparison and evolutionary analysis revealed that two CmHSP90 had the highest consistency with the HSP90 of Momordica charantia, Cucumis melo and Cucumis sativus, and the genetic distance was the closest. The qRT-PCR analysis showed that both CmHSP90 genes were induced by hot, cold, ABA, high-salt, H2O2, drought and SA (salicylic acid) treatments, but the response speed and intensity were not the same. Specifically, two genes responded strongly to hot and salicylic acid treatments for a short time. It is speculated that CmHSP90 gene may play a regulatory role in heat stress and salicylic acid signal pathway of Cucurbita moschata. The results provided a theoretical basis for further understanding the function of HSP90 and elucidating the stress resistance mechanism of Cucurbita moschata.
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