Cloning and Expression Analysis of Chalcone Synthase Gene PgCHS1 in Panax ginseng

Abstract: To clone the chalcone synthase (CHS) gene and analyze the relationship of CHS expression profiles and flavonoids content， anti-stress in Panax ginseng， total RNA from fresh 4-years roots of P. ginseng was extracted and synthesized to cDNA. Primers were designed based on the CHS sequence of transcriptome of P. ginseng. The full open reading frame (ORF) of CHS gene was obtained by reverse transcription polymerase chain reaction (RT-PCR) and PCR products were sequenced. The sequence was analyzed by bioinformatics. The expression profiles of CHS gene were identified by qRT-PCR， and the content of the total flavonoids was assayed in the roots， stems， leaves and hairy roots of P. ginseng. The CHS gene was cloned and designated as PgCHS1. The full ORF of PgCHS1 has 1 182 bp and encode 393 amino acids. The sequence analysis indicated that absolute conservation of Cys164， Phe215， His303 and Asn336 occur in PgCHS1 sequence of the catalytic center. Moreover， PgCHS1 protein exhibits strong conservation of residues shaping the geometry of the active site (Pro138， Gly163， Gly167， Leu214， Asp217， Gly262， Pro304， Gly305， Gly306， Gly335， Gly374， Pro375 and Gly376). The PgCHS1 gene expression level remained the highest in leaves， follow by stems， roots and hairy roots. Expression analysis of PgCHS1 in elicitor treatments showed that salicylic acid (SA) and methyl jasmonate (MeJA) obviously induced PgCHS1 expression. Total flavonoids content of P. ginseng also enhanced in response to SA and MeJA， which correlated with increased PgCHS1 expression. Induction of PgCHS1 by SA and MeJA suggested its involvement in production of flavonoids， providing protection from environmental stresses.

CSTR: 32200.14.cjcb.2018.12.0005