overview of the pvy management in france by the seed potato sector (powerpoint)

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
http://localhost/var/www/apps/conversion/tmp/scratch_4/BOQUEL.pptx


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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
http://localhost/var/www/apps/conversion/tmp/scratch_4/BOQUEL.pptxhttp://localhost/var/www/apps/conversion/tmp/scratch_4/BOQUEL.pptx


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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
http://localhost/var/www/apps/conversion/tmp/scratch_4/BOQUEL.pptxhttp://localhost/var/www/apps/conversion/tmp/scratch_4/BOQUEL.pptx


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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

overview of the pvy management in france by the seed potato sector (powerpoint)

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