Identification and Expression Analysis of Cytochrome P450 Genes Probably Involved in Triterpenoid Saponins Biosynthesis in Astragalus mongholicus.

Abstract

Cytochromes P450 (P450s) are one of the largest enzymatic protein families and play critical roles in the synthesis and metabolism of plant secondary metabolites. Astragaloside IV (AS-IV) is one of the primary active components in Astragalus herbs, exhibiting diverse biological activities and pharmacological effects. However, P450s involved in the astragaloside biosynthesis have not been systematically analyzed in Astragalus mongholicus (A. mongholicus). In this study, we identified 209 P450 genes from the genome of A. mongholicus (AmP450s), which were classified into nine clans and 47 families and performed a systematic overview of their physical and chemical properties, phylogeny, gene structures and conserved motifs. Weighted gene co-expression network analysis (WGCNA) revealed that AmP450s are critical in the astragaloside biosynthesis pathway. The expression levels of these AmP450s were verified by quantitative real-time PCR (qRT-PCR) analysis in the root, stem and leaf, showing that most AmP450s are abundant in the root. Additionally, the correlation analysis between gene expressions and AS-IV content showed that twelve AmP450s, especially CYP71A28, CYP71D16 and CYP72A69, may have significant potential in the biosynthesis of astragaloside. This study systematically investigates the P450s of A. mongholicus and offers valuable insights into further exploring the functions of CYP450s in the astragaloside biosynthesis pathway.