Barley powdery mildew resistance - will it happen to...
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Transcript of Barley powdery mildew resistance - will it happen to...
• Blumeria graminis f. sp. hordei • Obligate biotroph • Especially prominent WA • Susceptible Cultivars • 1.55 million ha sown in 2011
Loss
$ m
illio
ns
ABS 2012, Murray and Brennan 2010
Net blotch-spot form
(15)
Net blotch-net form
(10)
Powdery mildew
(33)
Leaf rust (11)
Rhizoctonia (6)
Major diseases of barley in WA. Million $ of loss 2008- 2009 indicated in parenthesis.
Barley Powdery Mildew
Not for
commerc
ial pu
rpose
s
Short latent period
Polycyclic reproduction
Progeny easily dispersed Large population size
Infect all life stages of host
Pathogen persistence over seasons
Large mono-culturing of susceptible host
Single site MOA used
Limited access to other MOA Prolonged use of single MOA
Fungicides with single target site
Extended exposure (spatial/temporal)
Multiple sprays per season
Dose of applied
Pathogen Characteristics
Fungicide Characteristics
Factors affecting fungicide resistance
Not for
commerc
ial pu
rpose
s
Short latent period Polycyclic reproduction
Easily dispersed progeny
Large population size
Infect all life stages of host
Persistence between seasons Large mono-culturing of susceptible host
Sexual Cycle
Asexual Cycle
Short latent period
Large population size
Polycyclic reproduction Infect all life stages of host
Persistence between seasons
Easily dispersed progeny
Pathogen characteristics
Not for
commerc
ial pu
rpose
s
Short latent period Polycyclic reproduction
Easily dispersed progeny
Large population size
Infect all life stages of host
Persistence between seasons Large mono-culturing of susceptible host
Short latent period
Large population size
Polycyclic reproduction Infect all life stages of host
Persistence between seasons
Easily dispersed progeny
CBH
% b
arle
y so
wn
Cropping season
Large mono-culturing of susceptible host
Pathogen characteristics
0%
10%
20%
30%
40%
50%
60%
70%
80%
90%
100%
2005 2006 2007 2008 2009 2010 2011 2012 2013
VSSMSMR-MSMRR
Not for
commerc
ial pu
rpose
s
Paynter et. al. 2011
Baudin
Not for
commerc
ial pu
rpose
s
Single site MOA used
Limited access to other MOA
Prolonged use of single MOA
Fungicides with single target site Extended exposure (spatial/temporal)
Multiple sprays per season
Dose of applied fungicide
Triazole
Triazole + Triazole
Triazole + QoI
APVMA
Fungicide characteristics
Single site MOA used
Limited access to other MOA
Prolonged use of single MOA
Fungicides with single target site Extended exposure (spatial/temporal)
Not for
commerc
ial pu
rpose
s
All registered fungicides for barley
contain a triazole
• Azoxystrobin + Cyproconazole • Epoxiconazole • Epoxiconazole + Pyraclostrobin • Flutriafol • Propiconazole • Propiconazole + Cyproconazole • Tebuconazole • Tebuconazole + Flutriafol • Tebuconazole + Prothioconazole • Triadimefon
Fungicides registered in WA
Eburicol
Ergosterol
14α-demethylase (Cyp51)
Not for
commerc
ial pu
rpose
s
Triazole sensitivity in barley powdery mildew
Triadimefon 0-
Flutriafol Tebuconazole
EC50
Not for
commerc
ial pu
rpose
s
2009
Not for
commerc
ial pu
rpose
s
2010
Not for
commerc
ial pu
rpose
s
2011
Not for
commerc
ial pu
rpose
s
2009 - 2011
Not for
commerc
ial pu
rpose
s
00.10.20.30.40.50.60.70.80.9
1
2009 2010 2011 2012 2013
Prop
ortio
n Lo
ss $
mill
ions
Y136F
Y136F + S509T
Susceptible cultivars + repeated selection pressure = recipe for fungicide resistance
DVVYDCPN…SMFSRPMAP DVVFDCPN…SMFTRPMAP DVVFDCPN…SMFSRPMAP
136 509 Amino acids
Not for
commerc
ial pu
rpose
s
Australian barley production
Murray and Brennan, 2010
• WA epidemic.
• Susceptible cultivars + reliance on single mode-of-action fungicides.
• Reduced control from triazole target gene mutations Y136F + S509T
• Average loss $33M ↑ ~$100M p.a.
Not for
commerc
ial pu
rpose
s
East $931M
Loss $100M
Barley powdery mildew loss
• WA epidemic.
• Susceptible cultivars + reliance on single mode-of-action fungicides.
• Reduced control from triazole target gene mutations Y136F + S509T
• Average loss $33M ↑ ~$100M p.a. • Mutations appearing
in the east of Australia
Murray and Brennan, 2010
Not for
commerc
ial pu
rpose
s
Murray and Brennan, 2010
Predicted barley powdery mildew loss
• WA epidemic.
• Susceptible cultivars + reliance on single mode-of-action fungicides.
• Reduced control from triazole target gene mutations Y136F + S509T
• Average loss $33M ↑ ~$100M p.a. • Mutations appearing
in the east of Australia
Not for
commerc
ial pu
rpose
s
• Blumeria graminis f. sp. tritici • Very similar to barley powdery mildew
• Characteristics • Life cycle – polycyclic • Host specific
• Severe infections yield
Wheat Powdery Mildew
Short latent period
Polycyclic reproduction
Progeny easily dispersed Large population size
Infect all life stages of host
Pathogen persistence over seasons
Large mono-culturing of susceptible host
Pathogen Characteristics
Not for
commerc
ial pu
rpose
s
0%
10%
20%
30%
40%
50%
60%
70%
80%
90%
100%
2004 2006 2008 2010 2012 2014
2015 Wheat Variety Guide DAFWA Bulletin 4864 Australian Crop Report ABRES June 2015
VS S MS MRMS
Are
a so
wn
Cropping season
WA wheat powdery mildew susceptibility
Not for
commerc
ial pu
rpose
s
0%
10%
20%
30%
40%
50%
60%
70%
80%
90%
100%
2004 2006 2008 2010 2012 2014
0%
10%
20%
30%
40%
50%
60%
70%
80%
90%
100%
2004 2006 2008 2010 2012 2014
Are
a so
wn
Cropping season
VS S MS MRMS
Mildew susceptibility of WA wheat
2015 Wheat Variety Guide DAFWA Bulletin 4864 Australian Crop Report ABRES June 2015
Not for
commerc
ial pu
rpose
s
PestFax Map, DAFWA
Not for
commerc
ial pu
rpose
s
PestFax Map, DAFWA
Not for
commerc
ial pu
rpose
s
PestFax Map, DAFWA
Not for
commerc
ial pu
rpose
s
Time (seasons)
Freq
uenc
y of
resi
stan
ce (%
)
High Impact
Lower Impact
10
80
70
60
50
40
30
20
90
100
0
Powdery mildew specific
Importance of early detection
Not for
commerc
ial pu
rpose
s
Importance of early detection
Idftjyi
Digital PCR
DVVYDCPN…SMFSRPMAP DVVFDCPN…SMFTRPMAP DVVFDCPN…SMFSRPMAP
Amino acids 136 509
Y136F
S509T
• Screen powdery mildew for the Y136F and S509T mutations
• High throughput
• Quantitative
• Sensitive
• Use on identified resistance mutations
Not for
commerc
ial pu
rpose
s
Lower Impact
100
Time (seasons)
Freq
uenc
y of
resi
stan
ce (%
) 10
80
70
60
50
40
30
20
90
0 0%
10%
20%
30%
40%
50%
60%
70%
80%
90%
100%
0.1% 1% 10% 50% 100%
Importance of early detection
Not for
commerc
ial pu
rpose
s
Not for
commerc
ial pu
rpose
s
Barley powdery mildew mutations
• S509T mutation
• Combined with Y136 = field resistance
Not for
commerc
ial pu
rpose
s
Wheat powdery mildew mutations
Not for
commerc
ial pu
rpose
s
In Conclusion
• Estimate the barley powdery mildew epidemic in WA costs ~$100M pa.
• Susceptible cultivars + fungicides from a single chemical class = build up of resistance.
• High levels of resistance with combination of two mutations. • Development of Digital PCR for high throughput screening for
resistance. • Mutations in barley powdery mildew found in WA are now
starting to occur in East Aust. • Precursor fungicide resistance mutations now found in wheat
powdery mildew isolates in East Aust. • Need to act quickly and effectively to avoid subsequent losses
from these pathogens.
Thanks Acknowledgements
Richard Oliver Fran Lopez-Ruiz Belinda Cox Simon Ellwood Julie Lawrence
Nick Poole Tracey Wiley
