Abstract: The CDS sequence of Jc5β-StR gene was cloned with Jatropha curcas cDNA as template，and analyzed by bioinformatics analysis. The opening reading frame（ORF）of Jc5β-StR was 1 173 bp encoded 390 amino acids. The predicted molecular weight was 44.23 kD，and theoretical isoelectric point（pI）was 5.22. Blast searching and phylogenetic analysis showed that Jc5β-StR had highest identity（87%）and closest relationships with the 5β-StR of Ricinus communis. Jc5β-StR was a short-chain reductase，containing a progesterone 5β reductase（5β-POR）in a family of short chain reductase（SDRs），and also 6 conserved domains of SDRs. Jc5β-StR expressed in different tissues of root，stem，leave，flower，seed capsule，and seed，the 1highest in seed；moreover，the expression gradually rose with the development of seed，and declined after peak in the later stage of seed development（50 d）. The abiotic stress such as NaCl，PEG，4℃，and mechanical damage resulted in the up-regulation of Jc5β-StR expression in varied level，indicating that Jc5β-StR involved in the response to abiotic stress.

Key words: Jatropha curcas L., Jc5β-StR, clone, bioinformatics analysis, expression analysis