Molecular cloning and characterization of chalcone synthase gene from Coelogyne ovalis Lindl. and its stress-dependent expression

• Published in: Gene Vol. 762; p. 145104
• Main Authors: Singh, Nutan, Kumaria, Suman
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 15.12.2020
• Subjects: Abiotic stress; Characterization; Gene expression; Orchid; Secondary metabolites; Orchid; ORF; Abiotic stress; PLBs; Gene expression; CHS; TFC; Characterization; FW; UTR; Secondary metabolites; RACE PCR; TAC; KC; PKS; qPCR; cDNA
• ISSN: 0378-1119; 1879-0038
• DOI: 10.1016/j.gene.2020.145104

[Display omitted] •A full-length cDNA of CHS gene was isolated and characterized from Coelogyne ovalis.•In silico analysis showed that CoCHS protein contained all motifs and signature sequence for the gene’s functions.•Expression of CHS transcripts was upregulated by abiotic stress (dark, cold, UV-B, wounding, salinity stresses).•A positive correlation existed between CHS expression and secondary metabolites content. Chalcone synthase (CHS, EC 2.3.1.74) is one of the key and rate-limiting enzymes of phenylpropanoid pathway which plays superior roles in the production of secondary metabolites. In the present study a full-length cDNA of CHS gene was isolated and characterized from Coelogyne ovalis, an orchid of ornamental and medicinal importance. The CHS gene sequence from C. ovalis (CoCHS) was found to be 1445 bp and comprised an open reading frame of 1182 bp, encoding for 394 amino acid residues. Further, the sequence alignment and phylogenetic analysis revealed that CoCHS protein shared high degree of similarity with CHS protein of other orchid species. It also confirmed that it contained all four motifs (I to IV) and signature sequence for the functionality of this gene. Structural modeling of CoCHS based on the crystallographic structure of Freesia hybrida indicated that CoCHS had a similar structure. Quantitative polymerase chain reaction (qPCR) disclosed that CoCHS was expressed in all tissues examined, with the highest transcript being in leaves, followed by pseudobulbs and roots. CoCHS expression was also evaluated in the in vitro-raised plantlets under the abiotic stress (dark, cold, UV-B, wounding, salinity). mRNA transcript expression of CHS gene was found to be positively enhanced and regulated by the different stress types. A correlation between the CoCHS transcript expression with flavonoid and anthocyanin contents revealed that a positive correlation existed between metabolites’ content and CoCHS expression within the in vivo as well as in the in vitro-raised plant parts.