Research on the formation of new virulent pathotypes of Synchytrium endobioticum (Schilb.) Perc., the causal agent of potato wart disease.

Jarosław PrzetakiewiczPlant Breeding and Acclimatization Institute – National Research Institute, Department of Plant Pathology, Laboratory of QurantineOrganisms, Radzików, 05-87 Błonie, Poland

Pathotypes in EPPO region.

• About 40 different pathotypes of the fungus were identified in

Europe (Baayen et al., 2006).

• New pathotypes have been detected recently: 38(N1) in Turkey

(Çakir et al., 2009) and 39(P1) in Poland (Przetakiewicz, 2015).

• New outbreaks have been observed in countries with a warmer

continental climate, such as Turkey, Georgia, Bulgaria or Greece

(Çakir, 2005; Dimitrova et al., 2011; Gorgiladze et al., 2014; I.

Vloutoglou pers. comm., 2015).

• Several Polish virulent isolates had the same profile as other ones

detected in other European countries

Polish map with marked districts where living spores of S. endobioticum were detected.

Only winter sporangia in

Bydgoszcz & Toruńdistricts

Only winter sporangia in Żywiec

district.

Warted plants & winter sporangia

Only winter sporangia in

Grodzisk district

A map of Lesser Poland Province with marked communes where S. endobioticum still occurs.

Dębno

Skawica

S. Beskidzka

Zawoja

N. Targ

Cz. Dunajec

B. Tatrzańska

M. Podhalański

R. Zdrój

Lesser Poland lies in the Vistula River catchment area.

Life cycle of S. endobioticum.

Differenti

al

cultivars

Nu

mb

er

of

test

ed

Ro

tte

n s

pro

uts

No

re

acti

on

Laboratory assessment

Tota

l

Mean

Score

Remarks

Resistant Susceptible Resis

tance

grou

p

Classification1 2 3 4 5

Evora 45 45 45 5.0 S2 Extremely susceptible

Irga 45 45 45 1.0 R1 Extremely resistance

Erika 45 45 45 4.0 S1 Slightly susceptible

Reaction of cv. Evora, Irga & Erika to pathotype 1(D1) 4 weeks after inoculation.

Reaction of cv. Erika, Irga & Evora to pathotype 1(D1) 4 weeks after inoculation (GL).

Warts from cv. Erika after the first passage.

• Pathotype determination of the first generation.

Warts from cv. Erika after the

second passage.

• Pathotype determination of the second generation.

Warts from cv. Erika after the third passage.

• Pathotype determination of the third generation.

Warts from cv. Erika after the

second passage.

• Pathotype determination of the fourth generation.

Step by step of modified Potoček’s tube test.

Plastic rings are fixed using warm paraffin.

Inoculation Incubation Visible proliferation on sprouts.

The warts ready for diagnostic.

Three generations of pathotype 1(D1) on cv. Erika (2013).

WS from p. 1(D1)

WS from I generation

WS from II generation

I

II

III

Reaction of cv. Irga to pathotype pathotype 1(D1) (left) and after tree generations on cv. Erika (right)–2 weeks after inoculation (GL, 2013).

I

II

III

Reaction of cv. Spunta to pathotype 1(D1) & warts from the 3rd

generation selected on cv. Erika (GL, 2013).

Reaction of cv. Erika after 2 generations (2015).

Reaction of. cv. Irga & Combi to warts from on warts of the 2nd generation selected on cv. Erika (GL, 2015).

Reaction of differential cvs. to isolates of S. endobioticumselected from 1(D1) on Erika after 2 generations (GL).

NoDifferential

cultivarsIsolates of S. endobioticum

#E/15/1 #E/15/2 #E/15/3 #E/15/4 #E/15/5 #E/15/6 #E/15/7 #E/15/81Deodara + + + + + + + +

2Tomensa + + + + + + + +3Eersterling + + + + + + + +

4Producent + + + + + + + +

5Combi + + + + + + + +6Saphir - - - - - - - -

7Delcora ± ± ± ± ± ± ± ±8Miriam - - - - - - - -

9Karolin - - - - - - - -10Ulme - - - - - - - -

11Asche Sämling - - - - - - - -

13Desiree ± ± ± ± ± ± ± ±

14Talent + + + + + + + +15Gawin - - - - - - - -

16Bałtyk + + + + + + + +17Giewont + + + + + + + +

18Universal + + + + + + + +

19Blanik + + + + + + + +20Irga + + + + + + + +

+ Positive reaction (big warts),

- Negative reaction (no warts),

± Intermediate reaction (partially proliferation of sprouts),

Virulence profiles of different pathotypes of S. endobioticum.

+ Positive reaction (big warts),

- Negative reaction (no warts),

± Intermediate reaction (partially proliferation of sprouts),

Cultivar Virulence profiles of S. endobioticum pathotypes

1(D1) 2(G1) 6(O1) 8(F1) 18(T1) 2(Ch1) 3(M1) 39(P1) #/E/15

Deodara + + + + + + + + +

Tomensa + + + + + + + + +

Eesterling + + + + + + + + +

Evora + + + + + + + + +

Producent - + + + + + + + +

Combi - + + + + + + + +

Spunta - + + + + + + + +

Saphir - + - - - - - - -

Otolia - ± - - - - - - -

Delcora - - ± + + + - + ±

Miriam - - - ± + ± - + -

Karolin - - - - - - - - -

Ulme - - - - - - - - -

Asche Sämling + + + + + - + - -

Désirée - - ± + + + - + ±

Talent - - - + + + + + +

Gawin - - - - - - - - -

Bałtyk - + ± + ± + + ± +

Giewont - - ± + + + + + +

Universal - + + + + + + + +

Blanik - - + + + + + + +

Irga - + + + + + + + +

Nicola - - - - - - - + -

Conclusions

• Cultivation of slightly susceptible cultivars to pathotype 1(D1) (in the fields infested by the spores of the fungus in regions with favorable climate for S. endobioticum) may leads to emergence of new virulent pathotypes.

• Under favorable conditions, the selection of virulent pathotypes require 2-3 seasons (years).

• The same virulent pathotype can be selected from 1(D1) on the specific cultivars many times in different regions.

Thank you for your attention