Quantification of curcumin and molecular analysis of curcumin synthase genes in <i>Curcuma alismatifolia</i> genotypes

ABSTRACT Curcumin content and expression patterns of curcumin synthase (CURS ) genes in three tissues (corms, leaves and inflorescences) of 16 Curcuma alismatifolia genotypes were analysed in this study. This study aimed to investigate the variability of curcumin content and the expression patterns of CURS genes in different tissues of various C. alismatifolia genotypes, in order to identify potential resources for curcumin extraction and genetic improvement. The curcumin synthase 2 (CURS2 ) and curcumin synthase 3 ( CURS3 ) gene sequences were successfully cloned. Significant variations in curcumin content were observed among different genotypes and tissues. In corms, Twister (0.299 mg · g −1 ) and Doitung (0.296 mg · g −1 ) had the highest curcumin levels. In inflorescences, Lanna Snow (0.375 mg · g −1 ) had the highest curcumin levels. In leaves, NewSolo (0.783 mg · g −1 ) had the highest curcumin levels. Quantitative PCR analysis revealed tissue-specific expression patterns of CURS genes: curcumin synthase 1 (CURS1 ) was highly expressed in corms, CURS2 in leaves and CURS3 in inflorescences. Additionally, CURS2 and CURS3 were successfully cloned from C. alismatifolia . Both genes have a CDS length of 1173 bp, encoding 390 amino acids, with high sequence conservation. Phylogenetic analysis indicated close evolutionary relationships between CURS genes and those from Curcuma xanthorrhiza, Curcuma longa and Zingiber officinale . This study provides a basis for curcumin extraction and genetic improvement of C. alismatifolia , and contributes to further research on curcumin biosynthesis.