Abstract Detail

Ecology/Pathology

Vandegrift, Roo [1], Blaser, Wilma [2], Campos-Cerda, Felipe [1], Heneghan, Allison [3], Carroll, George [1], Roy, Bitty [4].

Mixed fitness effects of grass endophytes modulate impact of enemy release and rapid evolution in an invasive grass.

Endophytic fungi in grasses are often considered to be mutualistic because they can increase host resistance to herbivory and drought. However, not all endophytes are beneficial to their hosts, but may instead be specialist enemies. Brachypodium sylvaticum is an invasive grass in the USA. In its European native range, it is always infected by the host-specific endophyte Epichloë sylvatica. While this fungus decreases herbivory, it also decreases the growth rate and size of infected plants, making them less competitive. After showing that B. sylvaticum has lost its endophyte in the invaded range, we use greenhouse assays to de-confound the effects of endophyte infection and origin to test assumption of the evolution of increased competitive abilities (EICA) hypothesis. Brachypodium in its invaded range appears to have lost tolerance mechanisms present in the native range, allowing Epichloë to greatly increase seedling mortality and reduce growth rates, supporting the EICA hypothesis.

1 - University of Oregon, Institute of Ecology and Evolution, 335 Pacific Hall, 5289 University of Oregon, Eugene, OR, 97403-5389, USA
2 - Swiss Federal Institute of Technology, Institute of Integrative Biology, Universitätstrasse 16, ETH Zentrum, CHN, Zuerich, CH-8092 , Switzerland
3 - New Mexico State University, Las Cruces, NM, USA
4 - University of Oregon, Biology, Institute of Ecology and Evolution, 335 Pacific Hall, 5289 University of Oregon, Eugene, OR, 97403-5289, USA

Keywords:
Biological invasion
enemy release hypothesis (ERH)
evol. of incr. compet. abilities
EICA
ERH
Brachypodium sylvaticum
endophyte
Epichloë sylvatica
germination
growth rates
fungal plant pathogen
mutualist-pathogen continuum.

Presentation Type: Offered Paper - Paper
Session: 16
Location: Room 104 AB/Kellogg Hotel and Conference Center
Date: Wednesday, June 11th, 2014
Time: 11:45 AM
Number: 16006
Abstract ID:129
Candidate for Awards:None