a multitrophic interaction between a fly, a fungus and orchardgrass in the willamette valley...
TRANSCRIPT
A Multitrophic Interaction A Multitrophic Interaction between a Fly, a Fungus between a Fly, a Fungus and Orchardgrass in the and Orchardgrass in the
Willamette ValleyWillamette Valley
Undergraduate Researcher: Denise Undergraduate Researcher: Denise BaumannBaumann
Mentor: Dr. Sujaya RaoMentor: Dr. Sujaya Rao
Oregon State UniversityOregon State University
Summer 2003Summer 2003
Orchardgrass in Orchardgrass in the Willamette the Willamette
ValleyValley
Dactylis glomerataDactylis glomerata
Approx. 20,000 acres Approx. 20,000 acres in the Willamettte in the Willamettte ValleyValley
Seed CropSeed Crop Forage CropForage Crop
Endophyte AssociationEndophyte Association
Single grass plant
Seed Stalk
Tillers
Fungal Stroma
Endophytic Fungi
+ +++
- --
-
- --
-
Spermatial Transfer
(Egg Deposition)
Sexual Development of the Fungus
(Egg Hatch)
(Larval Feeding)Harvest
(Pupae Formation)
Overwintering &New growth in Spring
(Adult Emergence)
Choke in orchardgrassChoke in orchardgrass((Epichloe typhinaEpichloe typhina))
Unfertilized
Fertilized Fungus
Fungal Stoma
Past ResearchPast ResearchBultman and White (midwest)Bultman and White (midwest)
Trials carried out in the wild (isolated grass Trials carried out in the wild (isolated grass plants)plants)
0-7 larvae per fungal stroma0-7 larvae per fungal stroma
63.8 % of stromata collected had 1 larva only 63.8 % of stromata collected had 1 larva only and less than 6% had >3 larvae per stromaand less than 6% had >3 larvae per stroma
Stomata with mesh bag had NO perithecia; Stomata with mesh bag had NO perithecia; uncovered stromata had 86.6 % peritheciauncovered stromata had 86.6 % perithecia
Fly is necessary for fungal fertilizationFly is necessary for fungal fertilization
HypothesisHypothesisIn this fly-fungal interaction in orchardgrass In this fly-fungal interaction in orchardgrass
in the Willamette Valley, the fly is not the in the Willamette Valley, the fly is not the sole factor for fungal fertilization.sole factor for fungal fertilization.
Objective OneObjective One
To determine whether this fly-To determine whether this fly-fungal interaction is fungal interaction is mutualistic.mutualistic.
Two treatmentsTwo treatments
1.1. Fly physically excluded, spore Fly physically excluded, spore allowedallowed
2.2. Control (no exclusion)Control (no exclusion)
ResultsResultsTreatment % Fertilization
Exclusion (Fly Only)
56% ns
No Exclusion 69% ns
Conclusion: The fly is not necessary for fungal fertilization in agrass field setting here in the Willamette Valley.
ns = no significant difference
Objective TwoObjective Two
Surveying orchardgrass in the Surveying orchardgrass in the Willamette Valley to determine Willamette Valley to determine the presence of the fly.the presence of the fly.
Orchardgrass SitesOrchardgrass Sites
Benton Co.
Linn Co.
Lane Co.
SRCorvallis
HPLR
CH
WD
AD
KRIB
PR ND
RR3RR2
RR1
Relationship between Avg Larva/stroma and % Larval infestation
0
10
20
30
40
50
60
RR1 RR2 KR SR WD IB HP RR3 LR AD PR ND CH
Field Site
Lar
val I
nfe
stat
ion
0
0.5
1
1.5
2
2.5
3
3.5
4
4.5
Avg
Lar
/Str
om
a
Larval Infested Stroma AvgLar/stroma
ResultsResults
0-10 larvae per fungal stroma0-10 larvae per fungal stroma
49.2 % of stromata collected had 1 49.2 % of stromata collected had 1 larva/stroma and 15 % had >3 larva/stromalarva/stroma and 15 % had >3 larva/stroma
When 10 larvae were present, >90% of the When 10 larvae were present, >90% of the fertilized stroma was consumedfertilized stroma was consumed
100 % of stromata fertilized irrespective of 100 % of stromata fertilized irrespective of larval presencelarval presence
Results continued…Results continued…
% Perithecial development at 3 sites% Perithecial development at 3 sites
SR = 94% (Average of .62 larva/stroma)SR = 94% (Average of .62 larva/stroma)
CH = 97% (no fly found at this site)CH = 97% (no fly found at this site)
RR1 = 95.7% (Average of 4.16 larva/stroma)RR1 = 95.7% (Average of 4.16 larva/stroma)
In Comparison…In Comparison… Past ResearchPast Research
1.1. Stated that the fly was Stated that the fly was obligatory for fungal obligatory for fungal fertilizationfertilization
2.2. 63.8% of stromata 63.8% of stromata collected had 1 larva collected had 1 larva only and less than 6% only and less than 6% had >3 larvae per had >3 larvae per stromastroma
3.3. Without presence of Without presence of the fly 0% fungal the fly 0% fungal stroma developed stroma developed peritheciaperithecia
My ResearchMy Research
1.1. Shows that there may Shows that there may be other factors be other factors besides the fly besides the fly fertilizing the fungus fertilizing the fungus here in the Valleyhere in the Valley
2.2. 49.2% of stromata 49.2% of stromata collected had 1 collected had 1 larva/stroma and 15% larva/stroma and 15% had >3 larva/stromahad >3 larva/stroma
3.3. 100% of fungal stroma 100% of fungal stroma developed perithecia developed perithecia irrespective of fly irrespective of fly presencepresence
Final SummationFinal Summation
It appears the fly benefits from this interaction in the
Willamette Valley; however it is unclear whether there is a
positive or negative effect on the fungus.
Future ResearchFuture Research
Preference StudiesPreference Studies Fungal host preferences by the flyFungal host preferences by the fly
Isolation trialsIsolation trials How does fertilization occur?How does fertilization occur?
Other factors of fungal fertilizationOther factors of fungal fertilization Wind, other insects, etc.?Wind, other insects, etc.?
AcknowledgementsAcknowledgements
Howard Hughes Medical Institute (HHMI)Howard Hughes Medical Institute (HHMI) Undergraduate Research Innovation, Undergraduate Research Innovation,
Scholarship, Creativity (URISC)Scholarship, Creativity (URISC)
Sujaya Rao, Jon Umble, Devorah Shamah, Sujaya Rao, Jon Umble, Devorah Shamah, Bill Pfender, Steve Alderman, Mark Bill Pfender, Steve Alderman, Mark Mellbye, Glenn Fisher, Lynn RoyceMellbye, Glenn Fisher, Lynn Royce
Orchardgrass Growers, especially James Orchardgrass Growers, especially James VanLeeuwenVanLeeuwen