Gene cloning and expression of a cystosolic small heat shock protein gene (HSP17.7) from Ageratina adenophora.

Cytoplasmic classI sHSP cDNA with full length of 683 bp was cloned from heat-shocked leaves of Crofton weed(Ageratina adenophora) by conducting RT-PCR and RACE-PCR.The accession number is EF105483 in the GeneBank.The semi-quantitative RT-PCR results revealed that the gene HSP17.7 could be detected and expressed significantly different between organ tissues at normal temperature.The transcription of HSP17.7 in leaves and stems was higher than that in roots.The expression of HSP17.7 significantly increased under heat treatment and chilling treatment in all root,stem and leaf tissues.To verify its possible function under heat and chilling stress,recombinant HSP17.7 was overexpressed in Escherichia coli.After the temperature being transferred from 37℃ to 50℃,which was known to cause cell autolysis,those cells with accumulated HSP17.7 exhibited improved viability compared with control.Similar results were observed under chilling treatment at 4℃ as well.Overall,the results indicate that sHSP of Crofton weed is positively involved in the responses to heat and chilling stress.