Abstract

The 70-kDa heat shock protein is a key factor for stress resistance and cellular network of plant. It plays an important role in protein assembly, folding, localization, degradation, tumor immunity etc. In this study, the complete HSP70-coding sequences were cloned from sweet potato by RT-PCR. They contain an open reading frame (ORF) of 1959 bp coding for a peptide of 652 amino acids with a molecular mass of 71.39 kD. Sequence analysis showed that sweet potato HSP70 gene has high homology with other plantHSP70 genes. The results from quantitative real-time RT-PCR demonstrated that the transcription level of the HSP70 gene in initial tuberous roots was much higher than that in young leaves, stems, mature leaves and fibrous roots. HSP70 gene was inserted into the vector pET-32a(+) by SLIC (sequence and ligation independent cloning) and successfully expressed in Escherichia coli BL21(DE3). 

Key words: Sweet potato, HSP70 gene, gene cloning, gene expression, quantitative RT-PCR analysis.