Abstract: The aims of this study are to clone the gene GrDXS encoding 1-deoxy-D-xylulose 5-phosphate synthase from Gentiana rigescens，and to analyze its expression. Based on the transcriptome of G. rigescens，a GrDXS gene was cloned from young leaves of G. rigescens by RT-PCR technology，and its prokaryotic and tissue-specific expression were also performed. The GrDXS gene（GenBank accession number：KJ624995）had a length of 2 145 bp coding for 714 amino acids，and the relative molecular weight of GrDXS protein was 76.75 kD with its pI of 6.93. GrDXS protein belonged to the member of DXS superfamily，and may localize in chloroplast，GrDXS protein composed of mainly random coil（47.06%）and α-helix（34.45%）. Four kinds of conserved domains: Thiamin diphosphate-binding fold（IPR029061，69-425，366-555，87-268，315-407，407-558），Transketolase-like，pyrimidine-binding domain（IPR005475，394-559，394-555），Transketolase C-terminal/Pyruvate-ferredoxin oxidoreductase，domain II（IPR009014，568-704，572-704），and Transketolase binding site（IPR020826，500-516），were all existing in GrDXS protein. GrDXS protein was the closest with CrDXS in Catharanthus roseus. The recombinant protein of GrDXS gene in Escherichia coli was approximately 100.00 kD（containing GST tag protein 26 kD），which was consistent with the anticipated size. GrDXS gene was primarily expressed in leaf.

Key words: Gentiana rigescens, 1-deoxy-D-xylulose 5-phosphate synthase, bioinformatics, expression pattern