Virus diseases of cereal crops in Germany

Virus diseases of cereal crops in Germany
- present situation and strategies for control
Thomas Kühne, Antje Habekuß
www.jki.bund.de

Cereal crops in German plant production in 2010
Total cropping area: 16,8 Mio ha = 47 % German territory
Yearly reduction: ~ 0,2 %
50
Institut für Resistenzforschung und Stresstoleranz
28
BaYDV WDV SBCMV WSSMV BaYMV BaMMV
Wheat X X X X
Barley X X X X
14
Rye X X X X
Triticale X X X X
3
5
Other
Wheat
Barley
Rye
Triticale

Classification of insect-transmitted viruses of cereals
Family Genus Species Vector
Luteoviridae Luteovirus Barley yellow dwarf virus-PAV Rhopalosiphum padi,
Sitobion avenae
Institut für Resistenzforschung und Stresstoleranz
Luteovirus Barley yellow dwarf virus-MAV Sitobion avenae
(unassigned) Barley yellow dwarf virus-RMV Rhopalosiphum maidis
Polerovirus Cereal yellow dwarf virus (RPV) Rhopalosiphum padi
Geminiviridae Mastrevirus Wheat dwarf virus Psammotettix alienus
Wheat strain
Barley strain

Impact of BaYDV and WDV on cereal cultures
annually and regionally quite different in Germany
� reduced winter hardiness of infected plants
� yield losses up to
• 95 % by early infection of young seedlings
• 25 % by infection during shooting stage
Institut für Resistenzforschung und Stresstoleranz

50
40
30
20
10
Virus attack of winter barley and winter wheat fields in spring
in Saxony-Anhalt
0
2
Attack (%)
23
18
3 3
26
Institut für Resistenzforschung und Stresstoleranz
30
10
45
1
6
4
Winter barley
(10-15 fields)
0,1
13
12
2
12
10
24
20
18
BYDV
WDV
4
40
10 10
1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2001 2002 2003 2004 2005 2006 2007 2008
0,1
Winter wheat
(10-16 fields)
2
1
0,1
6
10
0,4
4
3
17
16
5 x 30 samples / field
6
15

Reasons for the endangering of cereal crops by the
insect-transmitted viruses
Changes in cropping methods:
� Reduced tillage
• Volunteer cereal plants and wild grasses as infection sources are not
controlled
• Vectors have optimal conditions for multiplication and overwintering
� Early sowing dates
Institut für Resistenzforschung und Stresstoleranz

WDV attack of winter wheat in dependence on the
sowing date (2003/2004)
20
15
10
5
0
Attack (%)
6,5
13,5
16,7
Institut für Resistenzforschung und Stresstoleranz
0
Early February
April
Early July
0,4
Early sowing Late sowing
9.-17.09.03
n = 7 *
01.-15.10.03
n = 9
0,7
* 5 x 30 samples / field

Winter wheat field nearby Regensburg in July 2004,
sowing date - early September 2003
Institut für Resistenzforschung und Stresstoleranz

Reasons for the endangering of cereal crops by the
insect-transmitted viruses
Changes in crop production:
� Cultivation without plough
• Volunteer cereal plants and wild grasses as infection sources are not
controlled
• Vectors have optimal conditions for multiplication and overwintering
� Early sowing dates
Climate change
� Higher temperatures are favourable for vectors
• prolonged infection period in autumn
• more anholocyclic overwintering after warm winters
• shorter period of winter dormancy
• intensive multiplication leading to larger populations
• more generations per year
Institut für Resistenzforschung und Stresstoleranz
Insect-transmitted
viruses will become
more important

Influence of temperature and inoculation period on
infection rate of winter barley cv. Rubina with
BYDV-PAV transmitted by R. padi (D_02)
100
90
80
70
60
50
40
30
20
10
0
Infection rate (%)
10 15 20 25
Institut für Resistenzforschung und Stresstoleranz
Temperature (°C)
4 d acquisition period
4 days
2 days
1 day
Inoculation Inoculation

Relation between BYDV attack of winter barley in spring
and the temperature in autumn
50
45
40
35
30
25
20
15
10
5
0
Infection days autumn
Infection days: Number of days with mean daily temperature >= 10 °C from 1 st October till 31 st December
Institut für Resistenzforschung und Stresstoleranz
Year
Infection days
Infection rate
Attack in spring (%)
50
45
40
35
30
25
20
15
10
5
0

Control of insect transmitted virus diseases in cereal crops
� Agricultural methods
• removal of volunteer plants and other infection sources
• optimal sowing dates
• closed plant cover in the field
� Vector control
• no efficient chemical control of Psammotettix alienus
• control of aphids by
� seed treatment
� spraying of insecticides based on online advisory systems to
determine the action threshold and the dynamics of population
development (SIMLAUS, Rh. padi, S. avenae)
� Cultivation of tolerant / resistant cultivars
Institut für Resistenzforschung und Stresstoleranz

Current resistance situation
BYDV – barley
Gene/QTL Position Origin Identification Molecular marker
ryd1 H. vulgare `Rojo´ Suneson, 1955
Ryd2 3HL Ethiopian landraces Schaller et al., 1964
Institut für Resistenzforschung und Stresstoleranz
Ford et al., 1998
CAPS - Y1pPCRMF/R
Ryd3 6H Ethiopean landrace `L94´ Niks et al., 2004 SSR - HVM74
QTL-Post 2H H. vulgare cv. Post Scheurer et al., 2001 SSR - HVCSG
Ryd4 Hb 3HL H. bulbosum (Uruguay),
introgression in H. vulgare ‚Igri‘
Scholz et al., 2009 CAPS - TC134544
Ryd2 - already present in tolerant spring and winter barley cultivars in UK and France,
(cvs. Coracle, Vixen, Wysor, Venus and Naturel)
No BYDV-tolerant cultivars so far in Germany.

Breeding activities
Research Project (2007-2009)
Pyramiding of QTL with regard to the improvment of Barley yellow dwarf virus (BYDV)
tolerance of barley and genetic analysis of tolerance to Wheat dwarf virus (WDV)
• JKI-RS
• Four breeding companies
Institut für Resistenzforschung und Stresstoleranz

Breeding activities
� Combination of three known QTLs in DH-lines and estimation of their
influence on BYDV-tolerance
� Generation of two DH-populations (winter barley / spring barley)
`RIL K4-56´ x `DH21-136´ RIL K4-56´ x `Coracle´
`L94´ x `Vada´ `Post´ x `Vixen´ `L94´ x `Vada´ `CI 3906-1´ x (`Deba´ x `Abed´)
Ryd3 QTL_2H + Ryd2 Ryd3 Ryd2
• Genotyping with molecular markers specific for Ryd2, Ryd3 and Post-QTL
• Phenotyping in infection tests in the field
• 200 lines of each DH-population tested
• 2 variants (infected, control), 2 replications
• 4 locations
• 2 years
474 DH-lines 295 DH-lines
� 7 parameters
� symptom expression - virus concentration (ELISA),
� date of ear emergence, - plant height
� number of ears/plant
� yield
- thousand kernel weight
Institut für Resistenzforschung und Stresstoleranz
JKI,
Quedlinburg
Nordsaat Saatzucht,
Zuchtstation Gudow
Ackermann & Co.,
Irlbach
KWS Lochow GmbH,
Zuchtstation Bernburg

9
8
7
6
5
4
3
2
1
Ryd2
Ryd3
Phenotyping of spring barley DH-lines in 2008
Score
37*
a
Symptom expression
47 52 52
rr rs sr ss
+
+
n* = number of investigated lines, 200 totally
Institut für Resistenzforschung und Stresstoleranz
c
- +
-
+
b
+ -
+ -
Quedlinburg
Gudow
Bernburg
Irlbach
-
-
d
1,6
1,4
1,2
1,0
0,8
0,6
0,4
0,2
0,0
Reaction of DH-lines to
BYDV-PAV infection,
Irlbach, June 2008
a
Virus concentration
c
rr rs sr ss
Six DH-lines of each allele combination (single
plants; QLB, Irlbach) – May/June 2008
b
ELISA-Extinction at 405 nm
b

140%
120%
100%
80%
60%
40%
20%
0%
Ryd2
Ryd3
Phenotyping of spring barley DH-lines in 2008
Yield / Plant
a c b
Institut für Resistenzforschung und Stresstoleranz
Quedlinburg
Gudow
Bernburg
Irlbach
rr rs sr ss
+
+
- +
-
+
+ -
+ -
-
-
d
140%
120%
100%
80%
60%
40%
20%
0%
a
Ears / Plant
c b
rr rs sr ss
Relative values (infected variant in comparison to non-infected control)
GD=10,43;9,31;44,77;2,58%
d

Ryd2
Ryd3
QTL
9
8
7
6
5
4
3
2
1
Phenotyping of winter barley DH lines in 2007/2008
n*
Score
+
+
+
Symptom expression
51 30 31 54 26 49 24 16
+
+
-
+
-
+
Institut für Resistenzforschung und Stresstoleranz
+
-
-
n* = number of investigated lines
-
+
+
Bernburg
Gudow
Irlbach
Quedlinburg
a a a b a a
rrr rrs rsr rss srr srs ssr sss
-
+
-
BYDV-PAV infected Control
c
-
-
+
d
-
-
-
QLB, April 2008
1,6
1,4
1,2
1,0
0,8
0,6
0,4
0,2
0,0
1,4
1,2
1,0
0,8
0,6
0,4
0,2
0,0
Virus concentration – April / May 2008 (QLB, Gudow)
a
a
cd
de
rrr rrs rsr rss srr srs ssr sss
a
b
bc
Virus concentration – November 2008 (QLB)
a
b
c
rrr rrs rsr rss srr srs ssr sss
3 DH-lines of each allele combination
(single plants)
b
b
e
d
bc
d

120%
100%
80%
60%
40%
20%
0%
Ryd2
Ryd3
QTL
Phenotyping of winter barley DH lines in 2007/ 2008
ab
a
b
Yield / Plant
rrr rrs rsr rss srr srs ssr sss
+
+
+
+
+
-
+
-
+
Institut für Resistenzforschung und Stresstoleranz
b
+
-
-
ab
-
+
+
ab
-
+
-
c
-
-
+
Quedlinburg
Gudow
Bernburg
Irlbach
d
-
-
-
120%
100%
80%
60%
40%
20%
0%
Ears / Plant
a a b ab ab ab
rrr rrs rsr rss srr srs ssr sss
Relative values (infected variant in comparison to non-infected control)
c
d

Current resistance situation
WDV – barley, wheat
� Very limited data on resistance sources so far
� Reports from Czech Republic, France and Sweden describing quantitative
differences in virus attack of some winter barley and winter wheat cultivars
(virus tolerance)
� Benkovics et al., Plant Pathol. 59, 1144 (2010)
Hungarian wheat cvs. ‘Vekni’ and ‘Dalma’ may be valuable breeding resources
Institut für Resistenzforschung und Stresstoleranz

90,0
80,0
70,0
60,0
50,0
40,0
30,0
20,0
10,0
0,0
Evaluation for WDV-tolerance
� Testing of 248 winter barley accessions from 2002 to 2006
� cv. ‚Post‘ as WDV-tolerant standard
Relative performance of barley genotypes after WDV-infection in the field
2006
Relative infected to uninfected plot
Erfa Lunet Luxor Okal Perry Post Rubina Sigra Vixen
Institut für Resistenzforschung und Stresstoleranz
Plant height
Thousand kernel weight
Ears/Plant
Kernel weight/Plant
Gauze house 2005
Susceptible
line
`Post´

Breeding activities -
genetic analyses of WDV-tolerance of cv. ‚Post‘
Reaction of DH-population of the combination
‚Post‘ x ‚Vixen‘ to WDV-infection in gauze
house tests in 2007
Phenotypic characterisation of DH-lines with
respect to the yield determining factor plant
height as a prerequisite for QTL analysis and
development of molecular markers (2008/09)
Institut für Resistenzforschung und Stresstoleranz
(I)
18 Number of lines n=86
18 Number of lines n=86
18 Number of lines n=86
16
14
12
10
8
6
4
2
0
(II)
16 Number of lines n=77
16 Number of lines n=77
16 Number of lines n=77
16 Number of lines n=77
14
12
10
8
6
4
2
0
10 20 30 40 50 60 70 80 90 100
Vixen
Post
Degree of attack
Vixen
0-05 5-15 15-25 25-35 35-45 45-55 55-65 65-75
Plant height (relative infected to uninfected)
Post

Summary for BYDV and WDV
� Insect virus vectors benefit from higher temperatures due to climate change,
what makes virus transfer to plants more likely and will increase infection
pressure on cereal crops in Germany in future
� Pyramiding of resistance alleles significantly improved resistance of barley against
BYDV, with Ryd2, Ryd3 having a big and the ‚Post‘-QTL a weak effect , respect.
Results of DH-line testing indicate for quantitative resistance.
� High level of WDV tolerance in cv. ‚Post‘ was confirmed. This trait is apparently
polygenic.
Institut für Resistenzforschung und Stresstoleranz

Cereal crops in German plant production in 2010
50
Institut für Resistenzforschung und Stresstoleranz
3
5
28
14
Other
Wheat
Barley
Rye
Triticale
BaYDV WDV SBCMV WSSMV BaYMV BaMMV
Wheat X X X X
Barley X X X X
Rye X X X X
Triticale X X X X

WSSMV - synonym Wheat yellow mosaic virus
• Mostly in combination with SBCMV, frequently mixed infected plants
• Impact of WSSMV, synergistic effects ?
Vallega et al., 2003
Disease severity (Triticum durum) was significantly correlated with … SBWMV-ELISA value but not
with the WSSMV-ELISA value.
Nishio et al., 2010
Wheat yellow mosaic, caused by Wheat yellow mosaic virus (WYMV), is one of the most
devastating soil-borne diseases of winter wheat (Triticum aestivum L.) in Japan.
Economic relevance of WSSMV in Europe ?
Institut für Resistenzforschung und Stresstoleranz

SBCMV
Vector Polymyxa graminis
1982 first report (as SBWMV) for Germany (Proeseler et al., 1982)
1999 SBCMV but not SBWMV is widespread in Europe (Koenig et al., 1999)
2000 SBCMV and SBWMV are different virus species (Koenig & Huth, 2000)
2003 first report on SBWMV in Germany (Koenig & Huth, 2003)
Institut für Resistenzforschung und Stresstoleranz
Ute Kastirr

SBCMV
� Widespread in Germany, no systematic monitoring so far
� In contrast to France, UK, and Italy no yield losses in wheat, but in rye and triticale
� Resistance situation
Wheat
• Sbm1 locus on 5 DL of ‚Cadenza‘ (Bass et al., 2006) and ‚Tremie‘ (Perovic et al., 2009)
� inhibition of CP synthesis in roots, or
� proteolytic degradation of CP in roots (Lyons et al., 2009)
� lacking CP prevents virus transport from roots into shoots
• Sbm2 locus on 2BS (Bayles et al., 2007)
• Reasons for apparently different virulence of SBCMV isolates remain unknown
� Gödnitz / Walternienburg (D)
� Kent / Wiltshire (UK)
Rye
• Accessions with (quantitative) resistance have been identified and incorporated into
breeding programs
• Resarch project (2008-2011) to develop molecular markers for mapping of resistance genes
Institut für Resistenzforschung und Stresstoleranz

Cereal crops in German plant production in 2010
50
Institut für Resistenzforschung und Stresstoleranz
3
5
28
14
Other
Wheat
Barley
Rye
Triticale
BaYDV WDV SBCMV WSSMV BaYMV BaMMV
Wheat X X X X
Barley X X X X
Rye X X X X
Triticale X X X X

Institut für Resistenzforschung und Stresstoleranz
Deutsche Saatveredelung

BaMMV, BaYMV
Vector Polymyxa graminis
1978 first report for Germany (Huth & Lesemann, 1978)
1990 BaMMV and BaYMV are different species (Huth & Adams, 1990)
1993 RFLP mapping of rym4 resistance gene (Graner & Bauer, 1993)
Institut für Resistenzforschung und Stresstoleranz
Ute Kastirr

Resistance of barley to BaYMV and BaMMV
Current situation - 14 recessive resistance genes (H. vulgare)
- 2 dominant (H. bulbosum)
rym7
Rym16
rym4
rym5
rym6
rym10
rym11
rym1
rym8
rym9
rym12
rym13
Institut für Resistenzforschung und Stresstoleranz
rym3
rym15
Rym14
rym15
1H 2H 3H 4H 5H 6H 7H
rym2
Huth 1989,
BaYMV-2 rym4 (D)
Hariri et al. 2003; Habekuss et al. 2008
BaMMV-Sil rym5 (F, D)

Resistance of barley to BaYMV and BaMMV
� rym4 is still the predominant resistance gene in registered varieties
National list 2011 of winter barley varieties
Resistance No. of cvs. ~ %
susc. 12 17
rym4 53 75
rym5 1 1,5
rym15 1 1,5
? 3 4,5
Total 70
� Reasons for still existing dominance of rym4 varieties in barley assortment
• lower aggressiveness / fitness of BaYMV-2
• slow dissemination
• limited number of alternative varieties
• other reasons
Institut für Resistenzforschung und Stresstoleranz
Correct ?

Monitoring of BaYMV-2 in Germany in 2009/2010
Institut für Resistenzforschung und Stresstoleranz
• Plants of resistant cvs. with symptoms
• Tissue print immuno assay
• DAS-ELISA (BaYMV, BaMMV)
Partners:
• Deutsche Saatveredelung AG, Lippstadt
Michael Koch, Oliver Wellie-Stephan
• University (FH) Soest-Paderborn
Bernhard C. Schäfer
• Plant Protection Service
Field plot experiments for yield reduction (3 locations)
1977 1983 1986 1994
W. Huth

Monitoring of BaYMV2 in Germany in 2009/2010
Institut für Resistenzforschung und Stresstoleranz
• Plants of resistant cvs. with symptoms
• Tissue print immuno assay
• DAS-ELISA
Partners:
• Deutsche Saatveredelung AG, Lippstadt
Michael Koch, Oliver Wellie-Stephan
• University (FH) Soest-Paderborn
Bernhard C. Schäfer
Yield reduction of rym4 cvs. due to BaYMV-2 infection
2009 10 – 40 %
2010 10 – 25 %
control: rym5 cvs. and other breeding material

Conclusions
� nearly all current winter barley cvs. are susceptible to BaYMV infection
� rym4 resistance so far is not overcome by BaMMV
� BaMMV pathotype breaking rym5 resistance is still not widespread
due to low selection pressure (~ no cultivation of rym 5 cvs)
� ongoing breeding programs to improve the situation
Institut für Resistenzforschung und Stresstoleranz

Monitoring of BaYMV-2 in Germany in 2009/2010
VPg
RNA2
eIF4E
VPg
Institut für Resistenzforschung und Stresstoleranz
� Leaf sample of plants tested positive for BaYMV
from every city code area
� Samples from several infested experimental fields
� PCR amplification of the VPg-coding region
� Sequencing
• PCR products
• DNA clones
RNA1
3 general sequence variants for VPg protein
VPg
rym4 / rym5 encode for Eukaryotic Translation Initiation Factor 4E

New problems to await for cereal production in Germany ?
Soil-borne wheat mosaic virus (P. graminis)
• Wheat Sbm1 resistance in wheat is stable against SBWMV, too
• Barley resistance in some varieties observed
• Breeders use infested field for evaluation
Soil-borne barley mosaic virus (P. graminis)
2000 - first report for Japan (Shirako et al., 2000)
2007 - France (Hariri & Meyer, 2007)
2011 - Germany (Rabenstein et al., 2011)
• Wheat ?
• Barley all varieties tested so far were susceptible
• Breeders no activities
Wheat streak mosaic virus (Aceria tosichella)
Virus is widespread and important in Russia and Ukraine
Reports on occurrence from Poland, Czech Republic, Hungary, and Italy
• Wheat no efficient resistance
• Barley susceptible
• Breeders no activities
Institut für Resistenzforschung und Stresstoleranz

Acknowledgement
Julius Kühn-Institut
• Ute Kastirr
• Ursula Apel
• Doris Walther
• Dörte Grau
• Christine Riedel
• Frank Rabenstein
University (FH) Soest-Paderborn
• Bernhard C. Schäfer
We thank the Federal Ministry of Education and Research (BMBF), the Federal Ministry for Food,
Agriculture and Consumer Protection (BMELV) and the Gemeinschaft zur Förderung der privaten
deutschen Pflanzenzüchtung e.V. (GFP) for financial support of parts of these studies
(BMBF 03i0607A, BLE-28-1-41.002-06).
Institut für Resistenzforschung und Stresstoleranz
Nordsaat Saatzuchtgesellschaft mbH
• Eberhard Laubach
Deutsche Saatveredelung AG
• Michael Koch,
• Oliver Wellie-Stephan
Dr. J. Ackermann & Co. Saatzucht
• Klaus Einfeldt
KWS Lochow GmbH
• Jörg Grosser
• Hr. Koch
• Fr. Rossa
Saaten-Union Resistenzlabor GmbH
• Jens Weyen
• Birgit Schwier

Thank you
Institut für Resistenzforschung und Stresstoleranz
www.jki.bund.de

Frequency of aphid species at Aschersleben (1985-1999)
Metopolophium dirhodum
11 %
Brevicoryne brassicae
41 %
7 %
Rhopalosiphum padi
Institut für Resistenzforschung und Stresstoleranz
Sitobion avenae
5 %
Brachycaudus helichrysi
5 %
3 % Hyalopterus pruni
3 % Aphis fabae
other species
25 %

Reaction of wheat material in two different fields
Wheat
cvs.
Ares
Autan
Caesar
Charger
Claire
Corvus
Dekan
Hereward
Ökostar
Tremie
DAS-ELISA values (E 405)
SBCMV WSSMV
Go Wn Go Wn
0,0 0,4 0,0 0,0
0,0 0,2 0,0 0,0
0,0 0,7 0,0 0,3
0,0 1,1 0,0 0,3
0,0 0,4 0,2 0,1
0,0 1,2 0,0 0,0
0,0 0,7 0,0 0,0
0,0 0,9 0,0 0,0
0,0 0,4 0,0 0,0
0,0 0,2 0,0 0,0
Soissons
0,0 0,8 0,0 0,5
Ikarus 0,7 2,0 0,0 0,0
DH -lines
7
8
9
50
62
78
Susc. Control
0,0
0,0
0,0
0,0
0,9
0,0
1,7
Kastirr 2006, unpublished
0,2
1,1
0,3
1,3
2,6
1,8
1,9
0,0
0,0
0,0
0,0
0,0
0,0
0,8
Institut für Resistenzforschung und Stresstoleranz
0,0
0,0
0,0
0,1
0,0
0,0
1,3
� The incidence rate of translocation resistance
breakdown in resistant cultivars is
not correlated with
• the SBCMV isolate
• the concentration of the soil inocula
• concentration of P. graminis in roots
� WSSMV was not present in two different
SBCMV-infested soils (Wiltshire, Kent).
Lyons et al., 2009

SBWMV
• Worldwide occurrence, but
only at one location in Europe (D, Heddesheim) Koenig & Huth, 2003
• apparently no substantial spread since first detection,
but no systematic monitoring so far
Wheat
• Resistance of wheat against SBCMV (Sbm1, Sbm2) is stable Bayles et al., 2007; Lyons et al., 2009
Natural infection of barley by SBCMV
against SBWMV (D), too
remains questionable.
Barley
• 5 / 22 barley cultivars became infected, when cultivated in Lyons et al., 2008; Kastirr (unpubl.)
Barley plants are susceptible to another furovirus,
soil from Heddesheim
which is related to SBCMV and SBWMV with the
• None of the plants became infected in SBCMV-infested soil
preliminary name SBBMV (F. Rabenstein)
• SBCMV detection in barley cultivars ‚Tiffany‘ (FN298362) Vaianopoulos et al., 2009
and ‚Express‘ (FN298363) in Belgium, Mode of infection?
Institut für Resistenzforschung und Stresstoleranz
8th IWGPVFV Symposium 6-9 July 2011, Louvain-la-Neuve, Belgium
but

VPg
Multifunctional protein
• RNA replication
• cell-to-cell and long-distance movement
• translation
Grzela et al., 2008 / Rantalainen et al., 2008 / Tokuriki et al., 2009
• Potyvirus VPg is an intrinsically disordered molten globule-like protein with a
hydrophobic core
• Majority of viral proteins represent intrinsically disordered proteins (IDP‘s)
• Structural flexibility enables VPg to carry out a variety of functions
• As a result of molecular recognition VPg undergoes induced folding and structural
adaptation to the partner molecule (~ chaperone function of reaction partner)
There are limits in flexibility, because VPg of BaYMV1 is unable to properly adapt to the
rym4-encoded eIF4E molecule to trigger virus multiplication.
Flexibility of VPg may get altered by substitution of single amino acid residues.
Institut für Resistenzforschung und Stresstoleranz
8th IWGPVFV Symposium 6-9 July 2011, Louvain-la-Neuve, Belgium
• gene silencing suppression
• phloem loading of the virus
What do we currently know about sequence variability
of the VPg-coding region of BaYMV ?

Cultivation of virus tolerant cultivars
A
B
311bp
Ryd2
ryd2
253 bp
RIL K4-56 x Coracle
Genotype
Number of DH-lines
�² (1:1:1:1)=3.047
RIL K4-56 x DH121-136
Genotype
Number of DH-lines
Ryd2
Ryd3
68
Ryd2
Ryd3
QTL+
93
�² (1:1:1:1:1:1:1:1) =74.612
ryd2
Ryd3
Ryd2
Ryd3
QTL-
Institut für Resistenzforschung und Stresstoleranz
66
Ryd2
ryd3
76
49
YlpPCRM
ryd2
ryd3
85
Ryd2
ryd3
QTL+
43
Genotyping
ryd2
Ryd3
QTL+
92
50000
40000
30000
HVM74
20000
10000
0
160
178.99
177.94 180
190
200
199.07
145 150 150 150 155 155 155 160 160 160 165 165 165 170 170 170 175 180 185 190 195 200 205 21
0
35000
30000
25000
20000
15000
188bp 188.21 ryd3
10000
5000
0
160 180
187.21
186.18
190
200
199.06
145 150 155 160 165 170 175 180 185 190 195 200 205 210
30000
25000 HVCSG 211,45 211bp
positive allele QTL 2H
20000
15000
10000
210,42
212,48
213,51
209,38
344,95
343,90
5000 180 190 200
220 240 260 280 300
320
319,50
342,88
340
360
0
200 225 250 275 300 325 350
40000
35000
30000
218,75 218bp
negative allele QTL 2H
25000
217,71
20000
15000
10000
5000
0
180 190 200
219,78
216,67
215,62 220,82
214,58
220
240 260 280 300 320 340
351,26
350,20
349,17
360
200 225 250 275 300 325 350
ryd2
ryd3
QTL+
52
ryd2
Ryd3
QTL-
76
180bp
Ryd2
ryd3
QTL-
37
180.00 180.00 180.00 180.00 180.00 180.00 180.00 180.00
Size (nt)
ryd2
ryd3
QTL-
28
Ryd3

30
25
20
15
10
5
0
Virus attack of winter barley fields in Saxony-Anhalt
2006 / 2007
Infection rate (%)
2,4
24,2
(0-69,3)
(0-9,3) (0-3,3)
Institut für Resistenzforschung und Stresstoleranz
1,1
Dec. 2006 (n=11) April 2007 (n=9)
3,3
22,8
BYDV BYDV+WDV WDV
War Winter 2006/2007 besonders warm?
(0,7-9,3)
(2-41,3)
18,4
(0,7-32,7)
5 x 30 samples / field

Soil-borne viruses in cereal crops in Europe
Institut für Resistenzforschung und Stresstoleranz
Species Genus
Wheat Triticale Rye Barley Oat
WSSMV Wheat X spindle streak X mosaic virus X
Bymovirus
SBCMV Soil-borne X cereal mosaic X virus X
Furovirus
SBWMV Soil-borne X wheat mosaic X virus X X Furovirus
SBBMV AWMV Soil-borne Aubian ? wheat barley mosaic mosaic ? virus virus ? X Non Furovirus assigned ?
BaYMV Barley X yellow mosaic virus Bymovirus
BaMMV Barley mild mosaic virus X Bymovirus
OMV Oat mosaic virus X Bymovirus
OGSV Oat golden stripe virus Furovirus
8th IWGPVFV Symposium 6-9 July 2011, Louvain-la-Neuve, Belgium
X
X
France 1977
Germany 1983
Italy 1987
England 1999
Belgium 2005
Poland 2007

Resistance of barley to BaYMV and BaMMV
rym7
Rym16
Institut für Resistenzforschung und Stresstoleranz
rym4
rym5
rym6
rym10
rym11
rym1
rym8
rym9
rym12
rym13
rym3
rym15
Rym14
rym15
1H 2H 3H 4H 5H 6H 7H
rym2
rym4, rym5, rym6 are allels encoding mutant versions of
Eukaryotic Translation Initiation Factor eIF4E
Stein et al. 2005, Plant J. 42, 912
Kanyuka et al. 2005, Mol. Plant Pathol. 6, 449

eIF4E
eIF4E
cap
eIF3
eIF4G
Monzingo et al., 2007
eIF4A
VPg
AUG
Institut für Resistenzforschung und Stresstoleranz
plant mRNA
AUG
viral RNA
• apparently 2 spatially separated mutation sites for potyvirus resistance on eIF4E
• VPg may have 2 binding sites for optimal interaction
All potyvirus resistance mutation sites
Bymovirus resistance mutation sites
• precise contact points appear to be optimized for each virus/host pair by coevolution,
because they occur at different positions
Rhoads RE J. Biol. Chem. 284, 16711