Classification, biosynthesis, and biological functions of triterpene esters in plants

• Published in: Plant communications 2024-04, Vol.5 (4), p.100845-100845, Article 100845
• Main Authors: Liu, Jia, Yin, Xue, Kou, Chengxi, Thimmappa, Ramesha, Hua, Xin, Xue, Zheyong
• Format: Article
• Language: English
• Subjects: acyltransferases; biological functions; biosynthesis; classification; triterpene esters
• ISSN: 2590-3462; 2590-3462
• DOI: 10.1016/j.xplc.2024.100845

Triterpene esters comprise a class of secondary metabolites that are synthesized by decorating triterpene skeletons with a series of oxidation, glycosylation, and acylation modifications. Many triterpene esters with important bioactivities have been isolated and identified, including those with applications in the pesticide, pharmaceutical, and cosmetic industries. They also play essential roles in plant defense against pests, diseases, physical damage (as part of the cuticle), and regulation of root microorganisms. However, there has been no recent summary of the biosynthetic pathways and biological functions of plant triterpene esters. Here, we classify triterpene esters into five categories based on their skeletons and find that C-3 oxidation may have a significant effect on triterpenoid acylation. Fatty acid and aromatic moieties are common ligands present in triterpene esters. We further analyze triterpene ester synthesis-related acyltransferases (TEsACTs) in the triterpene biosynthetic pathway. Using an evolutionary classification of BAHD acyltransferases (BAHD-ATs) and serine carboxypeptidase-like acyltransferases (SCPL-ATs) in Arabidopsis thaliana and Oryza sativa, we classify 18 TEsACTs with identified functions from 11 species. All the triterpene-skeleton-related TEsACTs belong to BAHD-AT clades IIIa and I, and the only identified TEsACT from the SCPL-AT family belongs to the CP-I subfamily. This comprehensive review of the biosynthetic pathways and bioactivities of triterpene esters provides a foundation for further study of their bioactivities and applications in industry, agricultural production, and human health. Triterpene esters are secondary metabolites formed by modification of triterpene skeletons through oxidation, glycosylation, and acylation. In this review, Liu et al. classify triterpene esters on the basis of their skeletons and ligands, review their biosynthetic pathways and bioactivities, and analyze triterpene ester synthesis-related acyltransferases. This review provides a foundation for studying the biosynthesis pathway and biological activities of triterpene esters and their potential uses in industry, agricultural production, and human health.