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7/31/2019 Overview of the PVY management in France by the seed potato sector (PowerPoint)
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Overview of the PVY management inFrance by the seed potato sector
Presentacin por Ana Ponce de Len, Comit Nord/[email protected]
Glais
1,2
, L.; Boquel
3,5
, S.; Khelifa
4,5
, M. ; Ponce de Leon
5
, A. ;Deveaux5, V. ; Le Hingrat1, Y.
XXV Congreso ALAP
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- Transmission in a non persistent manner by at least 70 aphids species
(including Myzus persicae)
Vectors
Host range (500 plant species)Cultivated Solanacea
Potato virus Y(PVY): main characteristics
- Potyviridae family, type-member of Potyvirus genus
-Filamentous and flexuous particle (700 nm x 11 nm)
Potato virus Y
Genome
HC-Pro P3 CI VPg NIa NIb CPP135
VPg (A)n
100 nm
- Positive single strand RNA of almost 10 Kb
- Coding for 9 viral proteins
Ornemental plants Weeds
XXV Congreso ALAP
http://fr.wikipedia.org/wiki/Image:PetuniaHybridaPiebald.jpghttp://images.google.fr/imgres?imgurl=http://www.interet-general.info/IMG/Piment-Rouge-2.jpg&imgrefurl=http://www.interet-general.info/article.php3%3Fid_article%3D6554&h=340&w=219&sz=14&hl=fr&start=32&tbnid=GFjYge_NyVXlQM:&tbnh=119&tbnw=77&prev=/images%3Fq%3Dphttp://fr.wikipedia.org/wiki/Image:Patates.jpghttp://upload.wikimedia.org/wikipedia/commons/f/f3/Tomatoes-on-the-bush.jpg -
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XXV Congreso ALAP
Ensayos Comit Nord, 2010
-52% -39%
El PVY causa perdidas de rendimiento
Semente con 0% virusSemente con 0% virus
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PVYN
PVYNTN
PVYN-W
PVYN:O
Mosaic and/ornecrosis
Biological
type-O
type-N
type-N
type-O
Serological
PVYOP1 HC P3 CI NIa NIb CP
(Schubert et al 2007; Lorenzen et al 2006 et 2008; Glais et al non publi)
Molecular
PVY: main characteristics
Tobacco Potato
vein necrosis,leaf deformation
Mosaic and/ornecrosis
PTNRD
Mosaic
Straingroups
Variants
XXV Congreso ALAP
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1931
South ofAmerica
1935
O NFrance
1958
NHungary
1978
NTN
Poland
1984
N-WRussia
Tunisia
Lebanon
Japan
Oceania
Historic and distribution of PVY
in Europe
0%
20%
40%
60%
80%
100%
PVYN
YNTN
YN-WPVYO
0%
20%
40%
60%
80%
100%
PVYNYNTN
YN-W
PVYO
Today in USA
- PVYN and its variants (PVYN-W, PVYNTN) in relation with PVY unceasant evolution are widespreadin most potato growing areas in the world (independently of the closed systems)- The issue for the seed potato sector in France is to maintain a low level of PVY (as a viruscomplex) with a strong attention on PTNRD: thanks to specific management PVY incidence isvery low in France
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Main viral programs engaged bythe french seed potato growers
DISEASE
Aphids
PVY
Potato
To describe the biological,serological and molecular diversity of
natural PVY populations.
To identify viral moleculardeterminants involved in PVY
pathogenicity.
To identify the aphid vectors of PVY in natural conditions.
To evaluate the ability to transmitPVY to potato plants of different
aphid species.
To evaluate the aphid locomotiveand feeding behaviours allowing
PVY spreading.
To find solutions to protect the crop
DIAGNOSTIC
To develop serological and/or moleculardiagnostic tools to identify and to detect
PVY populations specifically.To control the sanitary
quality of seed potatoes.
Laurent Glais
XXV Congreso ALAP
Sbastien BOQUEL
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+N605O139 -
p1 HC-Pro P3 CI NIa NIb CP
+
-
+++
-+
-
Clone 1
Clone 2
Clone 3Clone 4
Clone 5
Clone 6
Clone 7
Identification of PVY pathogenicitydeterminants
-
Clone 11
Clone 12
Clone 13
Clone 14
Clone 8
-
+
-
+
Clone 9
Clone 10
Necrosis symptoms on tobacco plants
Involvement of two PVYgenomic regions (HC-Pro, NIa).
-
Three amino acid residues arecrucial in the induction of
tobacco vein necrosis symptomon tobacco plants.
Three amino acid residues arerequired and sufficient to confernecrotic properties of a PVYisolate with a non-necrotic HC-
Pro sequence.
Tribodet et al., 2005Faurez et al., 2012
Other determinants in otherparts of the PVY genome areinvolved in the tobaccopathogenicity.
XXV Congreso ALAP
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+N605O139 -
p1 HC-Pro P3 CI NIa NIb CP
+
-
+++
-+
-
Clone 1
Clone 2
Clone 3Clone 4
Clone 5
Clone 6
Clone 7
Identification of PVY pathogenicitydeterminants
-
Clone 11
Clone 12
Clone 13
Clone 14
Clone 8
-
+
-
+
Clone 9
Clone 10
Necrosis symptoms on potato tubers
-
In progress
XXV Congreso ALAP
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P1 HC P3 CI NIa NIb CP
(Schubert et al., 2007; Oshima et al, 2008 ; Glais et al., non published)
Analyse of the PVY serological diversity
1 26798
27
29
(Dhar et al., 1997 ; Chikh Ali et al. 2007 ; Karasev et al., 2009)
: amino acid sequence of O-type
: amino acid sequence of N-type
: Mutation point
Impacton the PVY antigenic properties :
- isolates escape to the serological detection
- false serological typing (mutations)
- some isolates are detected with both monoclonalantibodies against PVYN or PVYO isolates
What is the serologicalvariability of PVY isolates ?
XXV Congreso ALAP
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P1 HC P3 CI NIa NIb CP
(Schubert et al., 2007; Oshima et al, 2008 ; Glais et al., non published)
1 26798
27
29
(Dhar et al., 1997 ; Chikh Ali et al. 2007 ; Karasev et al., 2009)
: amino acid sequence of O-type
: amino acid sequence of N-type
: Mutation point
To improve academic knowledge of serological diversitywithin/between PVY strain groups and variants (numberand frequency of PVY antigenic structure )
To develop reliable serological diagnostic tools to allowright control of the potato seeds.
To set up a PVY monoclonal antibody librarylinked to the actual knowledge of PVYepitopic diversity (77 Mabs).
Analyse of the PVY serological diversity
Analyse of the Mab reactivity with acollection of 148 european and non europeanPVY isolates.
XXV Congreso ALAP
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Reactivity of 77 monoclonal antibodies
The 77 MAbs are distributed in 3main groups according to theaverage percentage of detectedserotype-N orO PVY isolates.
Almost all MAbs presentdifferent reactivity.
77 MAbs defined 75 reactivitygroups = at least 75 antigenicsites on PVY particles.
0
10
20
30
40
50
0 10 20 30 40 50 60 70 80 90
MAb polyvalent
: Mab2
: Mab YO/C
: Y123
: 4C3
: Mab YNINRA/FN3PT
: Mab YN-Sw
MAb anti-PVYO MAb anti-PVYN
: Mabs of the library: Mab YN-1F5
NberofdetectedPVYOi
solates(54)
Nber of detected PVYN isolates (94)
80% correspond to polyvalentMabs.
17% are close to Mabs specific toserotype-N isolates
3% are close to Mabs specific toserotype-O isolates
The PVY serological diversity is very large XXV Congreso ALAP
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Impact of these knowledge onthe PVY diagnosis
To identify molecular determinants
of PVY pathogenicity
To describe the serological PVY
diversity
To set up new reliable diagnostic tools for theidentification and detection of PVY isolates
The developed assays are transferred to the french organisationsin charge of the seed potato certification:
Molecular tools are developed with
non-neutral determinants link to thePVY pathogenicity (PCRq, SNP).
Selection of cocktails of monoclonal
antibodies allowing the detection ofspecific PVY populations.
XXV Congreso ALAPEach year production of ELISA reagents for the seed laboratories (>1,2 millions ELISA tests)
1
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Sbastien BOQUEL
Vector propensity of aphids to transmit
Potato virus Y (PVY) to potato
PhD funding by the Comit Nord Plants de Pomme de Terre (France)
Supervisors: P. Giordanengo et A. Ameline
Post Doctoral Research funded by SIPRE at Agriculture and Agri-Food Canada
1
Objective 1: Evaluate aphid vector activity
Objective 2: Evaluate aphid vector efficiency
?
3
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What is vector propensity?
Orientation
Virus acquisition
Aphid becoming infectious
Virus inoculation
Irwin & Ruesink 1986
Orientation
Represent the probability of a vector, having had the opportunity to acquire a virus on an infected plant, will
transmit it to a healthy one.
This concept includes two important notions:
3
Probing, Feeding
Vector activity
Behaviours adapted to virus transmission
Vector efficiency
Vectors ability to acquire and inoculate viral particles
Probing, Feeding
4
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Vector activity
Behaviours adapted to non-persistent virus transmission:
Vector which:
Vector activity involves 2 behavioural parameters:
Probing behaviour (needful for virus acquisition/inoculation) and...
locomotive behaviour (needful for virus spreading)
Irwin & Ruesink 1986
Lands on an infected plantRealizes intracellular punctures
MovesInitiates a quick probe
5
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Represents the probability of obtaining an infection with a given virus, using
a given vector under a given set of conditions
Measured by a relative efficiency factor (REF)
M. persicae: benchmark (value = 1)
Vector efficiency
Large heterogeneity within the same species
No. infected plants by the tested species
No. infected plants byM. persicae
van Hoof
1980
van Harten
1983
Piron
1986
Harrington
1989
de Bokx
1990
Sigvald
1996
Verbeek
2010
M. persicae 1 1 1 1 1 1 1
M. euphorbiae 0.58 0.1 0.2 0.91 0.07 - 0.00
A. fabae 0.41 0.1 0.14 0.9 0.07 0.1 0.04
A. pisum 0.28 0.05 0.17 0.45 0.11 0.7 0.07
R. padi 0.04 0.02 0.16 0.28 0.14 0.4 0.01
S. avenae 0.00 - 0.02 0.01 0.02 0.01 0.00
B. brassicae 0.00 - - 0.00 0.00 0.01 0.00
Aphids
Populations, clones
Virus
Strains and/or viral isolates
Viral concentrations
Plants
Species, varieties, phenological
stages
Set of conditions
Acquisition periods, humidity, etc.
Sylvester 1954 ; van Harten 1983
REF tested species =
13
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Vector propensity of aphids
Colonizing aphids
Sedentary behaviour with good
ability to transmit viruses
Non-colonizing aphids
Restless behaviour with middle/bad
ability to transmit viruses
Vector activity
Short probing delay
Intracellular punctures.
Landing on plants
Interplant movements
Vector efficiency
Middle to bad vectors
Vector activity
Short probing delay
Intracellular punctures
Landing on plants
Interplant movements
Vector efficiency
Good vectors
Non colonizing aphids represent a more important risk in PVY
epidemiology
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Cual es el modo de accin del aceite mineral?
Estudio del efecto del aceite mineral sobre la aquisicin del PVY porRhopalosiphum padi
La aplicacin de aceite mineral es el unico mtodo decontrol de la diseminacin del PVY utililizado hoy enFrancia
Trabajos llevados por S.BOQUELen Canada bajo la supervisin de YvanPELLETIER, en AAC, Fredericton (ver presentacin ALAP 2008)
Financiados por el Comit Nord
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Planta infectada
CS CA
Los estiletos transitan por via apoplasmica
Adquisicin / inoculacin durante breves picaduras intracelulares
Transmision de los virus no persistentes
Retencin de las particulas virales al nivel del acrostilo
Localizado en las partes distales de los estiletos
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Hyptesis:
El aceite minerala forma una capaaceitosa al nivel de los estiletos de los
pulgones inibiendo que las particulas
virales se fijen al nivel del acroestilo
Plante infecte
CS CA
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Zhang et al., Entomol. Exp. Appl. Soumis
Ethanol 95%
4
C
Stylet-20C
Corps
-20CAcquisition
Mtodo de deteccin del PVY en los estiletos del pulgn
Dissection
Arn -20C
Extraction
RT-PCRBroyage des tissus
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Parece confirmarse la hipotesis de la capa de aceita:
Se detecta PVY en los cuerpos pero no en los estiletos para las modalidades tratatadas
Las particules virales que se encuentran el cuerpo no se fijan en el acrostilo
La dosis de 10l/ha es eficaz para una proteccion durante 8 dias (ensayos en laboratorio)
Corrobora los resultados de campo (12 l/ha/semana)
El aceite mineral penetra en la planta (estudios preliminarios sobre la relacin entre laconcentracin de aceite mineral en la planta y la inibicin de la aquisicin)
Discusin
24h 48h 72h
72h
48h
48h 48h
48h
Proyecto Vegephy
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II- Cual es el mecanismo
de fitoproteccin?
IDesarrollar formulaciones
con aceites vegetales
POURCENTAGE DE VIROSE APRES PULVERISATION (24H AVANT L'INOCULATIONDU PVY)
42%
20%
32%
24%
34%
0%
10%
20%
30%
40%
50%
60%
Pourcentage
virose
temoins 733 799 801 803
a
b
abab
ab
Effect on vector population: ---Effect on vector devloppementupon the treated plant: ---
Effect on virus ---Effect on virus propagationwithin plant ---Effect on plant response ++Effect on virus-vectorinteraction ++
Estudios de varios origenes Con diferentes composiciones
fisico quimicas
% VIRUS
Proyecto VegephyM.Khelifa
How the seed potato growers manage to reduce PVY rate
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XXV Congreso ALAP
Crop
Quality of seedsQuality of tuber
production
SeedProduction
Aphids
- quantitative (species)- qualitative (demography)
Environmentparameters
- Landscape- Meteorology
p g g
Cultural practices- Choice of variety-Elimination of infected plants (early and repeated rogging), ofvolunteers- Insecticids- Mineral oil: only efficient treatment until now against PVY
- Choice of healthy prebasic material:Short multiplication scheme. The First tuberfor in vitro come from a National VarietySanitary Collection
- Importance of applying a low tolerance for PVYin certification: (Ver pres. G.CROUAU ALAP 2008)
-Visual control during vegetation-Post Harvest Check of the direct Progeny byELISA test in each generation-Visual control of the tubers: stricterrequirements than EU regulation: max 0,1% oftubers with necrosis
And also take into accountother infection sources: FarmSave Seed, Neighbouring crops,
Weeds
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Conclusin
En relacin a la complejidad de la diseminacin del PVY es esencialuna relacin estrecha entre investigacin/organizacin deproductores/servicios oficiales para tomar las buenas opciones en elmanejo del cultivo y para elaborar la reglamentacin
Colaboraciones deben hacerse a nivel internacional en un contexto despecializacin de los temas de investigacin con el objetivo decompartir experiencias y de reducir costes de cara a los riesgossanitarios: que interacciones con LatinoAmrica?
El objetivo final de la investigacin: semilla de alta calidad sanitaria
para dar en consumo buenos rendimientos y buena calidad
XXV Congreso ALAP
- Presentacin general Francia con enfoque a las actividades de la
FN3PT el Miercoles a las 16h00
- Visitenos: Stand MULTIPLANTAFN3PT con Marcio de Assis