Methyl jasmonate promote protostane triterpenes accumulation by up-regulating the expression of squalene epoxidases in Alisma orientale

Abstract

Protostane triterpenes, which are found in Alisma orientale, are tetracyclic triterpenes with distinctive pharmacological activities. The natural distribution of protostane triterpenes is limited mainly to members of the botanical family Alismataceae. Squalene epoxidase (SE) is the key rate-limiting enzyme in triterpene biosynthesis. In this study, we report the characterization of two SEs from A. orientale. AoSE1 and AoSE2 were expressed as fusion proteins in E. coli, and the purified proteins were used in functional research. In vitro enzyme assays showed that AoSE1 and AoSE2 catalyze the formation of oxidosqualene from squalene. Immunoassays revealed that the tubers contain the highest levels of AoSE1 and AoSE2. After MeJA induction, which is the main elicitor of triterpene biosynthesis, the contents of 2,3-oxidosqualene and alisol B 23-acetate increased by 1.96- and 2.53-fold, respectively. In addition, the expression of both AoSE proteins was significantly increased at four days after MeJA treatment. The contents of 2,3-oxidosqualene and alisol B 23-acetate were also positively correlated with AoSEs expression at different times after MeJA treatment. These results suggest that AoSE1 and AoSE2 are the key regulatory points in protostane triterpenes biosynthesis, and that MeJA regulates the biosynthesis of these compounds by increasing the expression of AoSE1 and AoSE2.

Effect of linolenic acid on triterpenoids production by the liquid fermentation of Antrodia cinnamomea

“…In summary, linolenic acid could regulate the expression of key enzymes involved in the triterpenoid biosynthesis pathway of A. cinnamomea, thereby promoting the biosynthesis of triterpenoids. Tian et al (2019) provided a similar conclusion when studying the mechanism of fatty acid derivative MeJA regulating the triterpenoid biosynthesis of Alisma orientale (Tian et al, 2019).…”

Pharmacological Properties and Molecular Targets of Alisol Triterpenoids from Alismatis Rhizoma

“…In the plant, protostanes are biosynthesized from squalene with the support of squalene epoxidases regulated by methyl jasmonate [ 6 , 46 ]. There are 22 alisol compounds, designated alisol A (Ali-A) to alisol V (Ali-V), and a multitude of related compounds bearing an acetate group at position 23 or 24 of the side chain appended to the tetracyclic protostane unit.…”

Metabolite and Gene Expression Analysis Underlying Temporal and Spatial Accumulation of Pentacyclic Triterpenoids in Jujube

“…Terpenoids' biosynthesis pathway began from the mevalonate (MVA) pathway in most higher plants [13]. 3-hydrocy-3-methylglutaryl-CoA reductase (HMGR), farnesyl pyrophosphate synthase (FPS), squalene synthetase (SQS), squalene epoxidase (SQE), and oxidosqualene cyclases (OSCs) are essential enzymes in triterpenoid biosynthesis [14]. SQS and SQE synthesize squalene and 2,3-oxidosqualene, important intermediates of the various triterpenes.…”