Plants are dependent on their root systems for survival, and thus are defended from belowground enemies by a range of strategies, including plant secondary metabolites (PSMs). These compounds vary among species, and an understanding of this variation may provide generality in predicting the susceptibility of forest trees to belowground enemies and the quality of their organic matter input to soil. Here, we investigated phylogenetic patterns in the root chemistry of species within the genus Eucalyptus. Given the known diversity of PSMs in eucalypt foliage, we hypothesized that (i) the range and concentrations of PSMs and carbohydrates in roots vary among Eucalyptus species, and (ii) that phylogenetic relationships explain a significant component of this variation. To test for interspecific variation in root chemistry and the influence of tree phylogeny, we grew 24 Eucalyptus species representing two subgenera (Eucalyptus and Symphyomyrtus) in a common garden for two years. Fine root samples were collected from each species and analyzed for total phenolics, condensed tannins, carbohydrates, terpenes, and formylated phloroglucinol compounds. Compounds displaying significant interspecific variation were mapped onto a molecular phylogeny and tested for phylogenetic signal. Although all targeted groups of compounds were present, we found that phenolics dominated root defenses and that all phenolic traits displayed significant interspecific variation. Further, these compounds displayed a significant phylogenetic signal. Overall, our results suggest that within these representatives of genus Eucalyptus, more closely related species have more similar root chemistry, which may influence their susceptibility to belowground enemies and soil organic matter accrual.

Item Type:	Refereed Article
Keywords:	Eucalyptus, phenolics, phylogenetic signal, roots, terpenes
Research Division:	Biological Sciences
Research Group:	Plant biology
Research Field:	Plant cell and molecular biology
Objective Division:	Expanding Knowledge
Objective Group:	Expanding knowledge
Objective Field:	Expanding knowledge in the biological sciences
UTAS Author:	Senior, J (Mr John Senior)
UTAS Author:	Potts, BM (Professor Brad Potts)
UTAS Author:	Davies, NW (Associate Professor Noel Davies)
UTAS Author:	O'Reilly-Wapstra, JM (Professor Julianne O'Reilly-Wapstra)
ID Code:	115706
Year Published:	2016
Web of Science® Times Cited:	23
Deposited By:	Plant Science
Deposited On:	2017-04-05
Last Modified:	2017-11-03
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