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The Dynamics of Multiple Infection in Pyrenophora semeniperda. Trevor Davis and Julie Beckstead, Gonzaga University, Department of Biology. Cheatgrass Invasion. Native to Eurasia Transported in crop seed Found in all U.S. states Outcompetes natives Alters fire cycle Persistent seedbank.
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The Dynamics of Multiple Infection in Pyrenophora semeniperda Trevor Davis and Julie Beckstead, Gonzaga University, Department of Biology
Cheatgrass Invasion • Native to Eurasia • Transported in crop seed • Found in all U.S. states • Outcompetes natives • Alters fire cycle • Persistent seedbank
Pyrenophora semeniperda • Fungus: “BFOD” • Possible biocontrol • Naturally occurring • Seed Pathogen • Generalist • High infection and death rates in cheatgrass
Multiple Infections • Species and strains • Common in nature • Complicated: competition, toxins, genetics, growth rate, virulence. • Varied response • May affect BFOD
Research Questions • Will co-infecting species and strains of fungi reduce BFOD’s potential as a biocontrol? • What characteristics of two co-infectors’ relationship determines their response to one another?
Materials and Methods • Double inoculation • Species and strains • Blotter-plate bioassays • Analyze seeds and stromata
Research Question • Will co-infecting species of fungi reduce BFOD’s potential as a biocontrol? Probably not.
Research Question • Will co-infecting strains of fungi reduce BFOD’s potential as a biocontrol? No.
Experiment 2 contd. Virulent Fast
Research Question • What characteristics of two co-infectors’ relationship determines their response to one another? Virulence > Growth Rate
Conclusions • Co-infectors will not affect BFOD’s performance as a biocontrol. • Minimal (<30% impact) • Reduction in virulence offset by high inoculum load • Inoculation combined with other methods
Conclusions contd. • Co-infections may be useful • Combine strains for application • Example: virulent kills, fast-growing “eats” • Lessens risk of non-target death • Location-specific genotypes
Acknowledgements • Dr. Julie Beckstead • Dr. Susan Meyer • Dr. David Boose • Dr. Ann Kennedy • Sandra Dooley • Laura Street • Kellene Bergen • Lindsay Poston • Lauren Miller • Kristina Bair • Stephen Harrison