1. Fungal endophytes of red fescue increase host survival but reduce tolerance to simulated herbivory
James Santangelo and Peter Kotanen
Department of Biology
University of Toronto Mississauga

2. Outline Introduction What are endophytes System natural history
Experiment: Effects of endophytes on plant performance
Results
Conclusion and significance

3. Endophytes are found in all plant species
Can be either bacterial or fungal
Live within plant tissues
Varied reproductive (i.e. sexual or asexual) and transmission (i.e. vertical or horizontal) modes

4. Fungal endophytes span the range of species interactions
Interactions are categorized based on fitness consequences
Don’t forget to mention that endophytes were traditionally studied for their effects on herbivores due to the alkaloids that they produce. Endophytes infect a broad range of plant species, among which is Red fescue.
Parasitism (-,+)
(e.g. Choke disease)
Mutualism (+,+)
(e.g. disease resistance)

5. Red fescue is commonly infected with fungal endophytes
Reproduces vegetatively and sexually
Forms large clonal patches
Dominant plant in our study system where it is heavily grazed by snow and Canada geese.

6. Endophytes can negatively impact Canada geese
Geese fed uninfected plants
Geese fed infected plants
Geese fed infected plants had reduced mass
Few studies examining endophyte-goose interactions
Conover and Messmer, The Condor (1996)

7. Kotanen and Abraham, Plant Ecology (2013)

8. Geese alter plant communities and soil properties
Endophytes obviously not acting as deterrents in this system. Plants are in a goose colony!!! No evidence of geese becoming ill.
Kotanen and Abraham, Plant Ecology (2013)

9. Role of fungal endophytes in this system is unexplored
We address the following questions:
Do endophytes influence plant survival?
Do endophytes influence plant growth and tolerance to simulated herbivory?
Do the above patterns depend on soil salinity?

10. Removing endophytes from plants
Endophyte free plant
Endophyte infected plant
dH2O
Fungicide

11. Experimental design Endophytes Clipping Salt Genotype 0 ppt 32 ppt
Endophyte free plant
Endophyte infected plant
Endophytes
Clipping
Salt
Genotype
0 ppt
32 ppt
64 ppt
Gen. 1
Gen. 3
Gen. 2
Gen. 4 X X X

12. Fully crossed design
48 treatments. 480 pots

13. Endophytes increase survival by 70%
Endophyte-free
Endophytes *

14. Endophytes reduced tolerance by 55%
Endophyte-free
Endophytes *

15. Endophytes did not influence plant growth
Endophyte-free
Endophytes

16. Returning to our questions…
Do endophytes influence plant survival?
YES! They increase survival.
Do endophytes influence plant growth tolerance to simulated herbivory?
NOT growth but they decrease tolerance
Do the above patterns depend on soil salinity?
YES! Survival was the same at high salinity

17. Conclusions
Endophytes appear to impose a trade-off – increasing plant survival but reducing tolerance to herbivory.
This trade-off may be modified by abiotic conditions (e.g. salinity).
Endophytes may help plants survive in saline soil.

18. Acknowledgements Graduate Students Krystal Nunes Colin Cassin Staff
Marianne Kalich
Brenda Pitton
Undergraduates
Ariana Longley
Cheyenne Cameron
OMNR
Ken Abraham
Sarah Hagey