Comprehensive Candidate Gene for Ginsenoside Rg1 Biosynthesis: Identification, Systematic Analysis, and Verification

Area of Science:

• Plant biochemistry
• Molecular genetics
• Pharmacology

Background:

• Ginsenoside Rg1 is a crucial compound in ginseng, indicating its quality and possessing diverse pharmacological effects.
• Ginsenoside Rg1 levels are complex quantitative traits influenced by multiple genes and environmental factors, necessitating genetic investigation for enhanced production.

Purpose of the Study:

• To identify and functionally characterize genes involved in ginsenoside Rg1 biosynthesis in ginseng.
• To elucidate the regulatory mechanisms of ginsenoside Rg1 production and establish a foundation for genetic improvement of ginseng.

Main Methods:

• Transcriptome analysis of 344 ginseng roots to identify candidate genes.
• Differential expression analysis, mutation screening, correlation analysis, and co-expression network analysis were employed.
• Functional verification through gene overexpression and RNA interference (RNAi) in ginseng hairy roots.

Main Results:

• Thirty-three candidate genes implicated in Rg1 biosynthesis were identified.
• A putative ginsenoside Rg1 biosynthetic pathway was inferred, and the role of PgRg1-021 was preliminarily clarified.
• Overexpression of PgRg1-021 decreased Rg1 levels, while RNAi increased them, confirming its negative regulatory role in Rg1 biosynthesis.

Conclusions:

• The study successfully verified the negative regulatory role of PgRg1-021 in ginsenoside Rg1 biosynthesis.
• This research provides essential gene resources for further pathway analysis and targeted breeding of ginseng.
• The findings serve as a valuable reference for identifying genes associated with other complex traits in plants.