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Comparison of host susceptibilities to native and exotic pathogens provides evidence for pathogen-imposed selection in forest trees

journal contribution
posted on 2023-05-19, 23:12 authored by Jules FreemanJules Freeman, Hamilton, MG, Lee, DJ, Pegg, GS, Brawner, JT, Paul TilyardPaul Tilyard, Bradley PottsBradley Potts
  • The extent to which spatial structuring of host resistance in wild plant populations reflects direct pathogen‐imposed selection is a subject of debate. To examine this issue, genetic susceptibilities to an exotic and a coevolved native fungal pathogen were compared using two Australian host tree species.
  • Damage to common host germplasm of Corymbia citriodora ssp. variegata (CCV) and Eucalyptus globulus, caused by recently introduced (Austropuccinia psidii) and native (Quambalaria pitereka and Teratosphaeria sp.) pathogens was evaluated in common‐garden experiments.
  • There was significant additive genetic variation within host species for susceptibility to both the exotic and native pathogens. However, susceptibility to A. psidii was not genetically correlated with susceptibility to either native pathogen, providing support for pathogen‐specific rather than general mechanisms of resistance.
  • Population differentiation (QST) for susceptibility to the native pathogens was greater than neutral expectations (molecular FST), arguing for divergent selection. Coupled with lower native, but not exotic, pathogen susceptibility in host populations from areas climatically more prone to fungal proliferation, these findings suggest that pathogen‐imposed selection has contributed directly to a geographic mosaic of host resistance to native pathogens.

Funding

Department of Industry, Science, Energy and Resources

History

Publication title

New Phytologist

Volume

221

Issue

4

Pagination

2261-2272

ISSN

0028-646X

Department/School

School of Natural Sciences

Publisher

Blackwell Publishing Ltd

Place of publication

9600 Garsington Rd, Oxford, England, Oxon, Ox4 2Dg

Rights statement

Copyright 2018 The Authors

Repository Status

  • Restricted

Socio-economic Objectives

Hardwood plantations; Native forests