Objective To clone the chalcone synthase gene SsCHS1 from Spatholobus suberectus and conduct bioinformatics and functional analyses, in order to elucidate its role in flavonoid biosynthesis. Methods Using cDNA from S. suberectus as a template, SsCHS1 was cloned by RT-PCR. Systematic bioinformatics analyses were performed on the sequence characteristics, protein structure, and function of the gene. An SsCHS1 overexpression vector was constructed and genetically transformed into Nicotiana benthamiana. The total flavonoid content and the expression levels of key enzyme genes in the flavonoid biosynthesis pathway in transgenic plants were determined. Results The full-length SsCHS1 gene was 1 176 bp, encoding a protein consisting of 391 amino acids, with a theoretical relative molecular mass of 42 825.35, an isoelectric point of 6.10, and was characterized as a hydrophilic protein. It showed high homology with CHS proteins from leguminous plants such as Glycyrrhiza uralensis and Glycine max. Promoter analysis revealed that SsCHS1 contains multiple cis-acting elements associated with hormone response, light response, stress response, and transcription factor binding sites. Functional analysis demonstrated that overexpression of SsCHS1 significantly promoted flavonoid accumulation in transgenic tobacco and upregulated the expression levels of key enzyme genes in the flavonoid biosynthesis pathway. Conclusion The SsCHS1 gene from S. suberectus promotes flavonoid biosynthesis. The identification of this gene provides an important theoretical basis and a candidate gene for further elucidation of the biosynthetic mechanisms of active components in S. suberectus.

Spatholobus suberectus Dunn  /  SsCHS1  /  gene cloning  /  flavonoid  /  gene function