Genetic and environmental parameters show associations with essential oil composition in West Australian sandalwood (Santalum spicatum)

Abstract

Santalum spicatum (R.Br.) A.DC is a West Australian sandalwood species highly valued for the sesquiterpene-rich oil in mature heartwood. The oil composition, particularly levels of the valuable sesquiterpenoids α- and β-santalol and the allergenic E,E-farnesol, are known to vary across its natural distribution. Our study investigated associations of oil characteristics in 186 S. spicatum trees in semiarid and arid regions of Western Australia with genetic structure, environmental parameters and morphological features. We found associations between oil composition and genetic structure, as well as between oil composition and environmental factors. Analysis of individuals using STRUCTURE revealed two major genetic clusters (K = 2), comprising trees from the arid north clustered together, and the semiarid south-west clustered separately. Mantel tests revealed a significant association between oil characteristics and genetic distance (r = 0.129, P = 0.02). There was considerable variation in the growing environment of S. spicatum. An Adonis test showed a significant association between oil composition and provenance (P = 0.001) and between oil composition and soil type (P = 0.002) but not oil composition and other environmental characters. Soil type was significantly related to santalol and E,E-farnesol content. No significant associations between oil composition and morphological features were identified.

Influence of Soil Nutrients, Tree Age, and Sandalwood Provenances on Sandalwood Oil Yield and Quality

“…Te phytochemical composition of genus Osyris includes volatile constituents that are important in essential oils and are known as sesquiterpenes. Te superiority of sandalwood oil is determined by the level of alpha (α) and beta (β) santalol relative to the international oil quality standards for these compounds [27]. Te GC-MS analysis in this study recognized compounds belonging to groups of hydrocarbons, fatty acids, esters, alcohols, amines, sesquiterpenes, among others, in Osyris oil.…”

Assessment of morphological and genetic variability through genic microsatellite markers for essential oil in Sandalwood (Santalum album L.)

“…In the present study, we found that the oil composition and genetic structure by the genic markers were not significantly correlated in S. album (Table 6). Likewise, the association of genetic structure as well as oil composition in S. spicatum was independent variables and determined by environmental factors mainly on geographical regions (soil-type factor) of the populations (Moniodis et al 2018). In this study, we found that the pattern of sandalwood oil component variation (α-santalol, trans-β-santalol, E-cis-epi-β bergamotol, and trans Z-α santalol) was significantly associated with environmental factors, which might affect the genetic structure variability.…”

Elicitors Modulate Young Sandalwood (Santalum album L.) Growth, Heartwood Formation, and Concrete Oil Synthesis

“…Moreover, global sandalwood resources have diminished since 1980, and demand is high [ 5 ]. In the long run, expanding plantations could alleviate the need to harvest natural populations but stringent conservation efforts are needed to thwart the decline of natural resources [ 6 ]. Enhancement of heartwood formation, especially through increasing plantation productivity, is an important means for creating sustainable sandalwood resources.…”