The Extended Community-Level Effects of Genetic Variation in Foliar Wax Chemistry in the Forest Tree Eucalyptus globulus.
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.
['Gosney|Benjamin|B|http://orcid.org/0000-0002-4127-5532', "O'Reilly-Wapstra|Julianne|J|", 'Forster|Lynne|L|', 'Whiteley|Carmen|C|', 'Potts|Brad|B|']
D000818:Animals D001181:Arthropods D005052:Eucalyptus D065928:Forests D005658:Fungi D008401:Gas Chromatography-Mass Spectrometry D014644:Genetic Variation D008954:Models, Biological D010641:Phenotype D018515:Plant Leaves D013729:Terpenes D014885:Waxes
Eucalyptus globulus Foundation trees Foliar terpenes Community genetics Cuticular wax compounds Extended phenotype