HAL Id: hal-02742329
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Submitted on 3 Jun 2020
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Assessing the mismatch between incubation and latency
for a vector-borne plant disease
Loup Rimbaud, Agnès Delaunay, Sylvie Dallot, Sonia Borron, Samuel
Soubeyrand, Gael Thébaud, Emmanuel Jacquot
To cite this version:
Loup Rimbaud, Agnès Delaunay, Sylvie Dallot, Sonia Borron, Samuel Soubeyrand, et al.. Assessing the mismatch between incubation and latency for a vector-borne plant disease. 2014 APS-CPS Joint Meeting, The American Phytopathological Society. Saint-Paul, USA., Aug 2014, Minneapolis, United States. �10.1094/PHYTO-104-11-S3.1�. �hal-02742329�
Loup Rimbaud, Ph.D. student
Montpellier SupAgro
UMR BGPI, Montpellier, France
Assessing the mismatch between incubation
and latency for a vector-borne plant disease
Latency vs. Incubation
t
i
Symptom expression
t
0
Inoculation
t
L
Infectious plant
t
L
= t
i
t
LATENCY
INCUBATION
t
Transmission
Influenza virus
Hepatitis B virus
Examples
Latency vs. Incubation
t
L
> t
i
t
LATENCY
INCUBATION
t
t
0
Inoculation
Symptom expression
t
i
t
L
Infectious plant
Transmission
Mycosphaerella fijiensis
Septoria nodorum
Examples
Latency vs. Incubation
t
L
< t
i
t
LATENCY
INCUBATION
t
t
0
Inoculation
Symptom expression
t
i
t
L
Infectious plant
Transmission
Rabies virus
Hepatitis A virus
Examples
t
LATENCY
INCUBATION
t
?
t
0
PPV inoculation
Symptom expression
t
i
t
L
Infectious plant
PPV
transmission
Disease
Sharka
Most damaging disease on Prunus
10 billions Euros of economic losses
worldwide in 30 years
Pathogen
Plum pox virus (PPV)
Potyvirus
Vectors
Aphids: > 20 species
Human: transfer of infected material
Hosts of
economic
interest
Prunus
e.g.: apricot, plum and peach trees
Sc o tt B a u er
Sharka management strategy in France
Since the 1990’s
Frequent visual inspections of the orchards
Removal of the symptomatic trees (or whole orchards)
Protection of the nurseries
Disappointing outcomes:
Costly strategy
Still many trees infected each year
0 1000 2000 3000 4000 5000 6000 2004 2005 2006 2007 2008 2009 2010 2011 2012 Year of prospection
Symptomatic trees detected in Gard (South of France)
(Data from regional offices of French food agency)
N u mbe r o f tr e e s
Infected trees without symptoms
cannot be detected?
Transmission
rate
Experimental approach
Inoculation
t
0Transmission 1
t
1= t
0+ 7 days
Transmission 2
t
2= t
0+ 11 days
Symptom expression
t
iN. benthamiana
Transmission 3
t
3= t
0+ 18 days
Δt
k
= t
k
- t
i
GF 305
A generic approach
for infectious diseases
Inoculation
Transmission
test
Symptom monitoring
No
symptom
1
2
3
Definition of 5 classes of leaves:
Highly severe
symptoms
Intermediary
symptoms
Light
symptoms
4
0
Severe
symptoms
Validation of the protocol by simulation
3 transition speeds to
simulate the latency period
3 scenarios for the
mismatch value
Unbiased and precise
estimate of the mismatch
Rimbaud et al., Acta Horticulturae, in press.
2 symptom expression dynamics to
simulate the incubation period
Data Models Fast Intermediate Slow DPI Inf e c ti ous pote nt ia l
t
m
s
m
e
max
.
4
max
1
Maximum
transmission rate
(plateau)
Transition speed
(slope at the
inflection point)
Mismatch between
incubation and latency
(abscissa of the inflection point)
Binomial generalized linear model
Parameters estimated by maximum likelihood
,
~
tested
infected
B
n
N
Pr o p o rtion o f in fec te d te st p lan tsDay after symptom expression
Result: a 0.85 day mismatch at the leaf scale
Symptoms appear on a
leaf 1 day before it rapidly
becomes infectious
INCUBATION
LATENCY
m = 0.85 day [0.51 ; 1.22]
τ
max
= 0.84
[0.78 ; 0.89]
s
m
= 0.40 day
-1
[0.22 ; 0.61]
Symptom severity class
Symptom category
No symptom Highly severe
symptoms Intermediary symptoms Light symptoms Severe symptoms
