The Extended Community-Level Effects of Genetic Variation in Foliar Wax Chemistry in the Forest Tree Eucalyptus globulus

Abstract

Genetic variation in foundation trees can influence dependent communities, but little is known about the mechanisms driving these extended genetic effects. We studied the potential chemical drivers of genetic variation in the dependent foliar community of the focal tree Eucalyptus globulus. We focus on the role of cuticular waxes and compare the effects to that of the terpenes, a well-studied group of secondary compounds known to be bioactive in eucalypts. The canopy community was quantified based on the abundance of thirty-nine distinctive arthropod and fungal symptoms on foliar samples collected from canopies of 246 progeny from 13 E. globulus sub-races grown in a common garden trial. Cuticular waxes and foliar terpenes were quantified using gas chromatography - mass spectrometry (GC-MC). A total of 4 of the 13 quantified waxes and 7 of the 16 quantified terpenes were significantly associated with the dependent foliar community. Variation in waxes explained 22.9% of the community variation among sub-races, which was equivalent to that explained by terpenes. In combination, waxes and terpenes explained 35% of the genetic variation among sub-races. Only a small proportion of wax and terpene compounds showing statistically significant differences among sub-races were implicated in community level effects. The few significant waxes have previously shown evidence of divergent selection in E. globulus, which signals that adaptive variation in phenotypic traits may have extended effects. While highlighting the role of the understudied cuticular waxes, this study demonstrates the complexity of factors likely to lead to community genetic effects in foundation trees.

Phytochemical variation in treetops: causes and consequences for tree-insect herbivore interactions

“…Studies in poplar trees have shown that intra-specific genotypic variation has strong effects on the concentration of compounds in the two major groups of phenolic defences, condensed tannins and salicinoids (e.g., Donaldson and Lindroth 2007). Genotypic effects on tree phytochemistry were, e.g., also shown in studies on willow (Barbour et al 2015), Eucalyptus (Barbour et al 2009; Gosney et al 2017) and birch (Haviola et al 2012). The phytochemistry of trees has been suggested to be the intermediate link between tree genes and the arthropods associated with trees by the genetic similarity rule (Bangert et al 2006).…”

Priority Actions to Improve Provenance Decision-Making

“…However, there are largely unappreciated extended effects of provenance choice on organisms that colonize and inhabit restoration plantings (Whitham et al 2006, Crémieux et al 2008, Bucharova 2017). Provenance effects have been shown to affect individual organism responses, as well as biotic communities both above- (Bucharova et al 2016, Gosney et al 2017) and belowground (Senior et al 2016, Gehring et al 2017, Urbina et al 2018. The coevolutionary relationships between local provenances and their dependent communities (e.g., Toju andSota 2005, Gehring et al 2017) further emphasize the importance of considering the extended effects of using local or nonlocal provenances on ecological networks.…”

Identification of novel compounds in rose absolute with gas chromatography/high‐resolution mass spectrometry

“…Phenylethyl heptanoate has been identified in another species of rose, Rosa rugosa , 38 and also in citrus, Stachys species and vanillin 39‐41 . Phenylethyl arachidate and phenylethyl behenate have been found in potato, poplar and eucalyptus, phenylethyl behenate was also found in Sambucus nigra 42‐46 . Phenylethyl heneicosanoate has also been descripted in eucalyptus 45 .…”

“…[39][40][41] Phenylethyl arachidate and phenylethyl behenate have been found in potato, poplar and eucalyptus, phenylethyl behenate was also found in Sambucus nigra. [42][43][44][45][46] Phenylethyl heneicosanoate has also been descripted in eucalyptus. 45 Phenylethyl linolenate has been identified in jasmine absolute and karo-karounde absolute.…”