environmental dependency of ranavirus/amphibian genotypic interactions
TRANSCRIPT
Pierre Echaubard,and David Lesbarrères
Ranavirus II, Knoxville, TN
Environmental dependency of Ranavirus/Amphibian genotypic interactions: a coevolutionary Rubik’s Cube
(Lambrechts et al 2005)
(Salvaudon et al 2005)
(Carius et al 2001)
(Lambrechts et al 2006)
(P1)
(P2)
GH x GP
indicate the potential for nontrivial coevolution based onFrequency dependent selection
(Wolinska and King 2009)
GH x GP x EReaction norm and Phenotypic
plasticity
On the importance of H-P genotypic interactions in understanding coevolution
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L > H
• Density is detrimentalPollutionCompetition for resources
• Virulence is context dependentVisible effects in low density only
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Context-dependent effects
Echaubard et al. 2010 PLoS One
Investigation of GHxGPxE
Hosts
Parasites
Environments
Wt FV3 Azac Ssme
Objectives
WtFV3 AzacFV3 SsMV Control
14 °C
Life history traits:-Size-Time to metamorphose-Growth rate-Mortality rate
22 °C
2
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WtFV3 AzacFV3 SsMV Control
Infection:1.0x104 pfu/ml)
Temperature (F1,369 =5.422;
p=1.07x 10-7)
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COLD WARM
We
igh
t (g
), ±
SE
COLD
WARM
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TEMP effects are SPECIES specific
TEMP affects Weight at
metamorphosis
Temp*Species*Strain (F23,3369 =7.584; p=2.2x 10-16)
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Azac Control SsMeV WtW
eig
ht
(g),
±SE
COLD LF
COLD WF1
COLD WF2
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Azac Control SsMeV Wt
We
igh
t (g
), ±
SE
WARM LF
WARM WF1WARM WF2
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LF WF1 WF2
We
igh
t (g
), ±
SE
COLD
WARM
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Temp*Species (F5,387 =21.98; p=2.2x 10-16)
STRAIN effects are conditional of both TEMP and SPECIES
-No difference between virus Strains in cold temperature but strong effect of Wt in Warm
-No difference for Wood frogs but strong effect of Wt in Leopard frogs
Weight at metamorphosis
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1 2 3 4 5 6 7 8 9 10
Cu
mu
lati
ve m
ort
alit
y ra
te (
%)
Time period
WARM
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Cu
mu
lati
ve m
ort
alit
y ra
te (
%)
Time period
COLD
Mortality
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1 2 3 4 5 6 7 8 9 10
Cu
mu
lati
ve m
ort
alit
y ra
te (
%)
Time period
WARM
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1 2 3 4 5 6 7 8 9 10
Cu
mu
lati
ve m
ort
alit
y ra
te (
%)
Time period
COLD
Significant Effects1. Temperature (Warm)(t =-2.33 ; p=0.021)2. Time(t =-3.553 ; p<0.0001)3. TempWarm:WF1(t =-3.553 ; p<0.02)4. TempWarm:WF2(t =2.165; p<0.03)5. WF2:Control (t =-4.188; p= 4.29x 10-5)6. Warm:Time (t =-2.513; p= 0.013)7. Warm:WF1:Control (t =-2.011; p= 0.045)8. Warm:WF2:SsMeV (t =2.034; p= 0.043)9. Warm:WF1:Wt (t =2.253; p= 0.025)10. Warm:Wt:Time (t =2.798; p= 0.005)11. Warm:WF2:Wt:Time (t =-1.808; p= 0.001)
-Mortality is influenced by both TEMP (1) and TIME (2)
- TEMP effect is different among SPECIES (3, 4)
- Mortality is dependant of STRAIN (7, 8, 9)
- TIME effect is dependent of TEMP (6), SPECIES and STRAIN (10,11)
Repeated measure ANOVA, Bonferroni correction applied
Conclusion/Interpretation
2 – Infection stimulates resource allocation to growth
End point Growth Rate
COLD WF Azac WF ControlLF Azac LF Control
Trade-off immuno/development
1 - Interaction Species*Strain
Growth Rate
3 - Below a certain threshold of virulence, allocation of more resources to growth than when confronted with a more virulent strain (Wt).
Susceptibility
Azac SsMeVWt
Virulence
Weight Growth RateMortality rate
LFFLIGHT or FIGHT?
Conclusions
The analysis revealed considerable variation in life history trait in response to:
Temperature Host Species Virus Strain
GHxGPxE
Amphibian / Ranavirus associated die-offs variability
Integrative approaches for H-P epidemiology and coevolution.
Take Home
Work in progress
-Pathogens co-occurrence and environmental variability
-TCID50 at different temperatures
-Strain variability and distribution
deletion of 757bp of coding region
