Identification of the Bisabolol Synthase in the Endangered Candeia Tree (Eremanthus erythropappus (DC) McLeisch).

Leticia Alves Gomes Albertti,Katarina Cankar,Katyuce Souza De Farias,Amanda Galdi Boaretto,Adele Van Houwelingen,Jules Beekwilder,Harro J Bouwmeester,Francel Verstappen,Thierry L Delatte,Carlos Alexandre Carollo

doi:10.3389/fpls.2018.01340

Abstract

Candeia (Eremanthus erythropappus (DC) McLeisch, Asteraceae) is a Brazilian tree, mainly occurring in the cerrado areas. From ethnobotanical information its essential oil is known to have wound healing and nociceptive properties. These properties are ascribed to result from a sesquiterpene alcohol, (–)-α-bisabolol, which is present at high concentrations in this oil. Bisabolol is highly valued by the cosmetic industry because of its antibacterial, anti-inflammatory, skin-smoothing and wound healing properties. Over the past decades, Candeia timber has been collected at large scale for bisabolol extraction from wild reserves and the species is thereby at risk of extinction. To support the development of breeding and nursing practices that would facilitate sustainable cultivation of Candeia, we identified a terpene synthase gene, EeBOS1, that appears to control biosynthesis (–)-α-bisabolol in the plant. Expression of this gene in E. coli showed that EeBOS1 protein is capable of producing (–)-α-bisabolol from farnesyl pyrophosphate in vitro. Analysis of gene expression in different tissues from Candeia plants in different life stages showed a high correlation of EeBOS1 expression and accumulation of (–)-α-bisabolol. This work is the first step to unravel the pathway toward (–)-α-bisabolol in Candeia, and in the further study of the control of (–)-α-bisabolol production.

Highlights

Essential oils from wild plants have been applied for many centuries in traditional medicine (Kamatou and Viljoen, 2010)
Candeia Bisabolol Synthase plant that has been identified as a source of high-value essential oil is the Candeia tree (Eremanthus erythropappus (DC) McLeisch), which primarily grows in the state of Minas Gerais in Brazil
The proportion of bisabolol in the sesquiterpene mixture greatly increases in the 10 year-old samples, which was consistent with previously published research (Mori et al, 2010)

Summary

Introduction

Essential oils from wild plants have been applied for many centuries in traditional medicine (Kamatou and Viljoen, 2010). One. Candeia Bisabolol Synthase plant that has been identified as a source of high-value essential oil is the Candeia tree (Eremanthus erythropappus (DC) McLeisch), which primarily grows in the state of Minas Gerais in Brazil. The oil which is steam distilled from trunks of this plants is known for its wound-healing, antinociceptive and anti-inflammatory properties (Sousa et al, 2008). A dominant active ingredient in Candeia oil is (–)-α-bisabolol, which is a monocyclic sesquiterpene alcohol (Figure 1). Chemical synthesis of bisabolol results in racemic mixtures, which have a lower bio-activity compared to the Candeia oil ingredient (Schwartz and Swanson, 1979). Candeia wood essential oil was reported to be dominated by (–)-α-bisabolol, up to a level of 66 to 91%. In leaves, (–)-α-bisabolol constitutes 2– 24% of the oil (Silverio et al, 2013; Dos Santos et al, 2015)

Methods

Results

Conclusion