ABSTRACT
Objective: To clone the chalcone synthase (CHS) gene in Carthamus tinctorius, to analyze the bioinformation of CHS, to compare the expression of CHS during the florescence, and to provide the foundation for composition and regulation mechanism of the active ingredients in C. tinctorius. Methods: RNA was obtained from fresh safflower corolla, cDNA was reversely transcriped, specific primers were designed, and then CHS was cloned. The protein characteristics was analyzed using bioinformatics, the phylogenetic tree of CHS was constructed using MEGA5.1, the expression of CHS during the florescence was analyzed using real time-PCR. Results: The 1 149 bp CHS sequence in C. tinctorius was obtained, which has a 1 041 bp ORF, encoding 346 amino acids. This protein belongs to the CHS family according to Blastp in NCBI. The CHS in safflower was similar to that in above 100 plants, and the similarities to Silybum marianum, Callistephus chinensis, Chrysanthemum x morifolium, and Gynura bicolor were respectively reaching 95%, 95%, 94%, and 94%. It has the closest relationship to S. marianum according to the phylogenetic tree using MEGA5.1. The CHS formula was C1678H2693N451O493S20 and the molecular weight was 37 700, with the isoelectric point of 6.10. The number of negatively charged amino acid residues (Asp + Glu) was 42, and the number of positively charged amino acid residues (Arg + Lys) was 38. The gene expression analysis showed that the highest expression of CHS in safflower was on day 3 of florescence, much higher than that on the other days. Conclusion: The CHS in safflower is successfully cloned, analyzed, and expressed, which provides the foundation for composite and regulation mechanism of the active ingredients in C. tinctorius.