ceresini florianopolis iiwbw_2016_recent_a

1

The recent emergence and evolution of the wheat blast species complex in Brazil!

!!

Paulo C. Ceresini and collaborators !

Prof. Paulo C. Ceresini UNESP ! ! !Dr. João L. N. Maciel Embrapa Wheat !!Dr. Vanina L. Castroagudín UNESP ! !Prof. Eduardo Alves UFLA Lavras!

! !!Dr. Silvino I. Moreira UFLA Lavras ! ! !Prof. Pedro Crous CBS The Netherlands !

!Dr. Anderson L. D. Danelli UPF Passo Fundo !Dr. Patrick Brunner ETH Zurich!

!Dr. Giselle Carvalho UNESP ! ! !Prof. Bruce A. McDonald ETH Zurich!

! ! ! ! ! ! ! ! ! ! !!! ! ! ! ! ! ! ! !Dr. Daniel Croll ETH Zurich!

!! ! ! ! ! ! ! ! !Dr. Ana Lídia Bonato Embrapa Wheat !

!! ! ! ! ! ! ! ! !Juliana T. A. Reges UNESP ! !!

Danilo A. S. Pereira ETH Zurich ! ! !Samanta C. Oliveira UNESP !! ! ! ! ! ! ! ! !Nadia Poloni UNESP !! ! ! ! ! ! ! ! !Adriano F. DoriganUNESP!

! ! ! ! ! ! ! ! !Matheus M. Dorigan UNESP!

! ! ! ! ! ! ! ! !Suellen SouzaUNESP!

Our Research Team

3

Wheat blast is caused by Pyricularia species closely related to the rice blast pathogen

Whe

at b

last

Ric

e bl

ast

Source: Danelli & Maciel

Source: Castroagudin, Moreira & Crous Source: Castroagudin, Moreira & Crous

A species with several names along its history

Magnaporthe oryzae: 2002 For both rice and wheat pathogens

Pyricularia grisea: 2007

Some resilience in accepting Magnaporthe oryzae

2014: Guess who’s back? Magnaporthe oryzae as the wheat blast pathogen

Adopting the new family name Pyriculariacea for the rice/wheat blast pathogen

“Species of Pyricularia s. str. belong to a monophyletic clade that includes all P. oryzae/P. grisea isolates tested, defining the Pyriculariaceae, which is sister to the Ophioceraceae, representing two novel families. These clades are clearly distinct from species belonging to the Gaeumannomyces pro parte / Magnaporthiopsis / Nakataea (syn. Magnaporthe) generic complex that are monophyletic and define the Magnaporthaceae.”

Pyricularia: From now on! Magnaporthe: No more.

“Magnaporthe oryzae (=M. salvinii), the type of Magnaporthe, forms a Nakataea asexual morph, and hence Luo & Zhang (2013) introduced the combination Nakataea oryzae for this fungus, as the name Nakataea (1939) is older than Magnaporthe (1972). This decision effectively reduced Magnaporthe to synonymy under Nakataea.“

“The majority of species formerly treated as Magnaporthe, fall in the Pyricularia complex (Murata et al. 2014).”

The recent origin and spread of wheat blast in South America

Sampling populations of Pyricularia from wheat and other grasses (N = 553) Eight regional populations of wheat-adapted Pyricularia from Central-Southern Brazil. Two host-distinct populations from other Poaceae species invasive to wheat areas from MS and PR. •  Brachiaria (Urochloa) brizantha •  Cenchrus echinatus •  Chloris distichophylla •  Cynodon dactylon •  Digitaria horizontalis •  Digitaria insularis •  Digitaria sanguinalis •  Echinochloa crus-galli •  Eleusine indica •  Panicum maximum •  Panicum repens •  Rhynchelytrum repens •  Sorghum sudanense One rice-adapted population.

Characterization of Pyricularia from wheat and other grasses

Genotypes 11 SSRs

DNA sequences Genomic data 10 housekeeping genes ~434’000SNPs

cytB and cyp51 (mtDNA) from 17 entire genomes AvrCO39 .

PCR assays

AvrCO39 AvrPITA

Mating types

Phenotypes Pathogenicity to barley, oat, rice, signalgrass and wheat Virulence on leaves (7 wheat cultivars + barley + rice)

Virulence on ears (7 wheat cultivars + barley) Sensitivity to QoI (strobilurins) and triazole fungicides

Sympatric samples: Wheat-derived isolates 76 Other Poaceae 26 Rice 23 Pyricularia grisea 1 P. pennisetigena 1

3301 bp sequenced 552 polymorphic sites 30 fixed mutations among groups

Genes ACT (actin) BAC6 βT-1 (beta-tubulin) CAL (calmodulin) CH7-BAC7 CH7-BAC9 CHS1 (chitin synthase 1) EF-1α (translation elongation factor 1-alpha) MPG1 (hydrophobin) NUT1 (nitrogen regulatory protein 1)

Comparisons of 10 genes in 125 Pyricularia strains show divergence between strains infecting

wheat, other Poaceae, or rice

% divergence (only fixed mutations within a particular group) Pgt vs. PoT = 0.50% Pgt vs. PoO = 0.53% PoT vs. PoO = 0.16% Isolates causing wheat blast could be separated into two distinct phylogenetic clusters: Cluster I = Pgt and II = PoT, with a high posterior probability (P= 0.99). Cluster II is further subdivided in two clades (1 and 2), distinct from the rice blast pathogen PoO.

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Three independent emergences for the wheat blast in the Brazilian agroecosystem.

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0.99

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BPP

BPP = Bayesian Posterior Probability

Castroagudin et al. (2016)

Pyricularia graminis-tritici sp. nov. From our Brazilian bio-diverse agroecosystem! (Castroagudin, Moreira, Crous et al. 2016)

Pyricularia graminis-tritici sp. nov. From our Brazilian bio-diverse agroecosystem! (Castroagudin, Moreira, Crous et al. 2016)

To our knowledge, P. graminis-tritici sp. nov. is still restricted to Brazil, but obviously represents a serious threat for the cultivation of wheat globally.

Pathogenicity spectra of Pyricularia graminis-tritici (Pgt) and P. oryzae pathotypes Triticum (PoT) and Oryza (PoO)


Pathogenicity spectra of Pyricularia graminis-tritici (Pgt) and P. oryzae pathotypes Triticum (PoT) and Oryza (PoO)


Barley Oat Signal grass Wheat Rice

Pgt + + + + - PoT + + + (1)/ -(2) + - (clades 1 and 2)

PoO + + - + + Wheat blast isolates from Pgt or PoT do not infect rice,

but they all infect barley, oat and signal grass (except PoT clade 2). Rice blast isolates (PoO) infect barley, oat, and wheat, but not signal grass.

The hypothesis of ”host-specific forms” does not hold for the wheat blast pathogens.

The distribution of the wheat blast pathogens varies according to a temperature cline

Prevalent in warmer Central Brazil.

RS SP MS PR Rice

Mato Grosso do Sul

MS

Minas GeraisMG

GoiásGO

São PauloSP

ParanáPR

Rio Grande do Sul

RS

Distrito Federal

DF

BRAZIL

Weeds - derived

0.8

0.6

0.4

0.2

Prop

ortio

n

Pyricularia graminis-tritici sp. nov.

N = 146on wheat

Central Brazil

DF + GO

MG

MS

SP

PRRS

Distribution towards

A

B

t test p value = 0.0061

SouthernBrazil

43%

The distribution of the wheat blast pathogens varies according to a temperature cline

Predominant in Southern Brazil.

0.8

0.6

0.4

0.2

Pyricularia oryzae pathotype

Triticum

Central Brazil

SouthernBrazil

Distribution towards

DF + GO

MG

MS

SP

PRRS

A

B

t test p value = 0.006

Mato Grosso do Sul

MSMinas GeraisMG

GoiásGO

São PauloSP

ParanáPR

Rio Grande do Sul

RS

Distrito Federal

DF

BRAZIL

57%Pr

opor

tion

N = 193 on wheat

Major Interpretation 1

Blast on wheat and other invasive Poaceae hosts from the Brazilian agroecosystem

is a complex disease caused mainly by two Pyricularia species:

Pyricularia graminis-tritici sp. nov. (Pgt)

Pyricularia oryzae pathotype Triticum (PoT).

…with broader host range within the Poaceae

but with ecotype differences.

Two other Pyricularia species cause blast on wheat, oat and Urochloa

Pyricularia species associated with blast on several poaceous hostsinvasive of wheat fields

Pyricularia graminis-tritici

Pyricularia oryzae

pathotypeTriticum

Other Pyricularia

species

N = 76

*Identified phylogenetically according to Klaubauf et al. 2015, Studies in Mycology.

N = 38

N = 13

N = 25

Pyricularia zingibericola *

Pyricularia spp.

Pyricularia pennisetigena *

Pyricularia grisea

Cenchrus echinatus

Urochloa spp.

Panicum maximum

Urochloa spp.

Panicum maximum

Chloris distichophyllaAvena sativa

Urochloa spp.Panicum maximum

Digitaria sanguinalis

2014

Pp = Pyricularia pennisetigena Pz = Pyricularia zingibericola

Two other Pyricularia species cause blast on wheat, oat and Urochloa

SNA. res.

(2014)Studiesinmycology,79,85-120.

Pg = Pyricularia grisea Pgt = Pyricularia graminis-tritici Pp = Pyricularia pennisetigena Pz = Pyricularia zingibericola

Pyricularia species

Diseased leaf area (%)

Two other Pyricularia species caused blast on wheat, oat and Urochloa

N=3639

Sympatric samples from Brazil Wheat-derived isolates 08 Other Poaceae 09

Phylogeny reconstruction •  Using RAxML

•  ~434,000 SNPs from the entire genome •  The dataset was analyzed using alignments against

the 70-15 reference genomes (Bowtie2 aligner) •  Used only SNPs genotyped among at least

90% of all isolates (i.e., very closely related isolates may be slightly more differentiated

due to SNPs only callable within a subgroup)

Compilation of available Pyricularia genomic data

•  Darren Soares / Exeter •  NCBI draft assemblies (several) •  Chiapello et al. (GBE 2015) / Montpellier

Genomic data comparisons of SNPs in 17 Pyricularia strains confirms the divergence between strains infecting

wheat, other Poaceae, and rice

0.2

Mo401.4

K96-07

PY35.3

Mo4603.4

MoK84-01

BM1-24

K93-16K96-11

PY6025

PY86.1

12.0.009i

P131

BR32

12.1.205

MoCQ11

Y34

K88-24

12.0.368

K91-13

Mo2303.1

12.1.053i

TH12-rn

MoJS25

12.1.127

Mo1801.4

MoKJ201_3

12.0.012i

PY5035

PH14-rn

MoHB12

PY5002

363

Mo1106.2

TH16

12.0.345i

12.1.169

HN19311

PY0925

Mo1836.3

4091 -5 -8

GY11

PY36.1

MoZJ15

MoGX01

12.0.534i12.0.642i

IT10

K98-02

PY5003

Mo4403.2

FJ81278

12.1.117

US71

BR29

12.0.326

MoAH06

MoSC05

PY6017

CA205

K88-07K91-30

12.0.555i

12.1.032i

FR13

B157MG01

PR72

98 -06

GOV41

PY6045

PY5033

70 -15

PY5010

PY6047PY25.1

12.0.007i

12.1.204

K98-10

Mo903.4

MoGD22

CD156

K91-10

MoHN06

MoJL10

MoNX37

12.1.037

Unknown host (Brazil)

Oryza sativa

Setaria italica


Triticum aestivum

Triticum aestivum

Triticum aestivum

Cenchrus echinatus

Eleusine indica

Triticum aestivum

Triticum aestivumTriticum aestivumTriticum aestivumTriticum aestivum

Urochloa ssp.Urochloa ssp.Urochloa ssp.


Triticum aestivum

Urochloa ssp.Echinochloa crusgalliAvena sativa

Triticum aestivumTriticum aestivumTriticum aestivum

Eleusine indica

Weeping lovegrass isolateCross between K76-79 (host: weeping lovegrass)and WGG-FA40 (host: finger millet)(Valent et al. 1986)

Chiapello et al. (GBE 2015)Ceres in i / McDonald / Croll

NCBI (various)Soares / Exeter

Data source

Triticum aestivumTriticum aestivumTriticum aestivumTriticum aestivum

Pgt

Pgt

PoT

PoT

PoT

Pgt

PoO

Pyricularia grisea ( Brazil)

Whole-genome phylogenetic tree built using RAxML with ~434,000SNPs. *The effect of genotyping rates per SNP was tested and found not significantly influencing the branching of the tree.

Wheat-infecting (and other poaceous hosts-) strains

Rice-infecting strains

PoO

The hypothesis of ”host-specific forms” does not hold for the wheat blast species complex.

Major Interpretation 2

Wheat blast and related strains (Pgt and PoT) found on different hosts showed overall much more polymorphism than the rice-infecting strains (PoO). No strict host specialization among the different clusters. Wheat blast might have originated from multiple sources and/or maintains significant genetic variability.

Evidence supporting the scenario of one disease, two major species: Pgt and PoT

RST values

0.24 0.24

RST values

0

0.25

0.50

1.00

0.75

completly

N = 208 MLMS genotypes

PoT0.843** 0.846**

Pgt PoT PoO

RST values in bold colored p values at _ = 0.01 (**)

PoO0.057**

Pgt -

-

-

rectangle

Current subdivision between Pgt and PoT

Subdivision among the two blast pathogens and PoO

High historical asymmetrical migration rate from Pgt to PoT

A coalescent-based genealogical analyses of population size and migration rates (Beerli and Felsenstein, 2001, Proc. Natl. Acad. Sci. 98:4563-4568) using SSR markers.

MIGRATION RATE AND POPULATION SIZE ESTIMATION

Migrate-n version 3.6.11 [June-18-15] Compiled for a PARALLEL COMPUTER ARCHITECTURE One master and 66 compute nodes are available.

Markov chain settings: Long chainNumber of chains 1

Recorded steps [a] 8334Increment (record every x step [b] 500Number of concurrent chains (replicates) [c] 6Visited (sampled) parameter values [a*b*c] 25002000Number of discard trees per chain (burn-in) 500Forcing percentage of new genealogies 0.10

Multiple Markov chains:Static heating scheme

5 chains with temperatures100000.00 10000.00 1000.00 100.00 1.00

Swapping interval is 10.0

20.0

40.0

60.0

80.0

100.0

120.0

Pgt

PoT PoO

0.0

20.0

40.0

60.0

80.0

100.

0

120.

0

0.0

20.0

40.0

60.0

80.0

100.0

120.0

Number of migrants exchanged/generation��e2Nm)

Historical migration estimates using the coalescent modelEvidence that the PoT population from wheat may be derived from an original Pgt population.

No differentiation between populations of Pgt from wheat and other poaceous hosts in Brazil

RST values

0.24 0.24

RST values

0

0.25

0.50

1.00

0.75

completly

N = 79 MLMS genotypes

Pgt

RST value is non-significant ( p = 0.32)

0.004Pgt (wheat) NS

(other poaceous hosts)

Populations from the two host groups had the same genetic structure.

Other poaceous hosts for Pgt: Avena sativa, Cenchrus echinatus, Cynodon spp.,

Digitaria sanguinalis, Elionurus candidus, Echinochloa crusgalli, Eleusine indica, Rhynchelytrum repens, and Urochloa spp.

Major Interpretations 3 •  Pgt populations from wheat and other poaceous hosts had

the same genetic structure. •  Among these grass species Urochloa is a widely grown

pasture grass occupying more than 90 million ha in Brazil, we propose that Urochloa provides a major source of wheat blast inoculum.

…and may be the preferred host for pathogen recombination.

Urochloa brizantha cv. Piatã

A mixed reproductive system Some clonality but gametic equilibrium in most of the locus pairs

Ratio MAT1-1 : MAT1-2

Pgt PoT

QoI-R cytB H1 15 : 1 18 : 1QoI-S cytB H9 1 : 1 1 : 5

Selection for QoI resistance increased the frequency of MAT1-1 / QoI-R strains

Despite the high selection against MAT1-2 QoI-S on wheat, the pathogens have potential for sexual reproduction on non-sprayed grasses.

Skewed mating types ratios

Phalaris canariensis (bird seed)

Oryza sativa cv. Primavera

Oryza sativa cv. Relâmpago

Oryza sativa cv. Yin Lu(Red rice)

Urochloa Mulato hybrid(signal grass)

Hordeum vulgare cv. BR Elis

(barley)Hordeum vulgare

cv. MN73Secale cereale

cv. BR1 (rye)

Avena strigosa cv. Embrapa 29 Garoa

(black oat)

Setaria italica(foxtail millet)

Triticum aestivumBRS 264 (wheat)

Triticum aestivumMGS Brilhante

XTriticum secalecv. IAC Canindé

(triticale)

Ascocarps abundantly

formed in senescent

tissues from wheat and other poaceous hosts inoculated with

both fungal mating types.

Source: S. I. Moreira

Co-inoculation of MAT1-1 x MAT1-2 lineages Pyricularia graminis-tritici

Major Interpretations 4

The genetic structure consistent with a mixed reproductive system includes regular cycles of recombination followed by clonal expansion. The fungal biology observations reinforces the population genetics evidence in favor of a mixed reproductive system.

Rapid local adaptation in populations of the wheat blast pathogens They have become resistant to QoI fungicides in ~10 years

Haplotype % isolates Host

H1 (QoI-R) 71% (Pgt and PoT) Wheat / other Poaceae

H2-H4 (QoI-R) 2% (Pgt and Pg) Other Poaceae

H5-H8 (QoI-R) 7% (Pgt , Pp, Pz, and Pg) Other Poaceae H9 (QoI-S) 20% (Pgt and PoT) Wheat / Other Poaceae

H7H6

H5H1

H3

H9H8

H4

H2

Other Poaceae

Rice-S

Triticum and other Poaceae

2005

DF

GO

MG

MSPR

RS

SP

Other Poaceae

PRMG

PRMS

MS

2005

DF MG

MS PR

Oth

er P

oace

ae

MS

PR

QoI Resistant

QoI Sensitive

cyt B haplotypes

PR

MSMSPR

Haplotypic variation at the citB gene

Castroagudin et al. 2015. Phytopathology 105:284-294

Sampling year % resistance isolates 2005 ~ 36 % 2012 ~ 80%

Resistance to azoxystrobin (100 ppm)

Progressive local adaptation in the wheat blast pathogens They have become quantitatively resistant

to azole fungicides in ~25 years

Freq

uenc

y

n= 44 MS

n= 26 DF/GO

n= 19 RS

n= 27

n= 28

n= 36

MG

SP

PR

EC 50 (ppm) to tebuconazole

0.6 0.8 1.0 1.2 1.4 0.6 0.8 1.0 1.2 1.4

20

15

10

5

0

15

10

5

0

10

8

6

4

2

0

1086420

1086420

15

10

5

0

H1PR, MS, RS,

MG, SP, DF_GO

165 95.9

H2 MG 1 0.6H3 PR,SP 1 0.6H4 SP, DF_GO 1 0.6H5 DF_GO 1 0.6H6 DF_GO 1 0.6H7 RS 1 0.6H8 RS 1 0.6

Total 6 172 100

LocationHaplotype N %N % N %

64 35.6 101 56.1

1 0.61 0.6

1 0.61 0.61 0.61 0.6

1 0.669 38.3 103 57.2

Pgt PoT

doses tebuconazol (ppm)

tebuconazole (ppm )

1210

48i

1211

30

0

20

40

60

80

100

Rela

tive

grow

th (

%)

doses of tebuconazole (pp

MO121048i

MO121130

Populations

cyp51 A

Poloni et al. 2016

Level of tebuconazole tolerance = 35 – 70 X higher than the labeled field dose Only few PoO isolates from rice were sensitive!

Several non-synonymous mutation detected in the cyp51A gene.

Emergence of 10 - 26 pathotypes that show cultivar specialization and host tissue specialization

Source: Cristina Boaretto, Anderson Danelli, João L. Nunes Maciel

Maciel et al. 2014. Phytopathology 104:95-107

Rapid local adaptation in populations of the wheat blast pathogens They have become host specialized in ~25 Years

Rapid local adaptation in populations of the wheat blast pathogens:

Latit

ude

(S -

N)

Longitude (W - S)

0 200 400 kmUruguay

Argentina

Paraguay

Bolivia

South America

Atlantic Ocean

Brazil

-3

0°

-2

5°

-20°

-1

5°

-

10°

-5

°

0°

-70° -65° -60° -55° -50° -45° -40° -35°

Pyricularia graminis-tritici (Pgt) 90 Pyricularia oryzae pathotype Triticum (PoT) 55

Total 145

MS = 38

RS = 15

MG = 22

SP = 5

DF_GO = 36

PR = 29 N

Sampling strategy for virulence grouping

High “race” diversity based on seedling reaction. Race A is virulent on all wheat + oat cultivars.

Complexity of virulence groups varied.

Source: Cristina Boaretto, Anderson Danelli, João L. Nunes Maciel / Maciel et al. 2014. Phytopathology 104:95-107

Rapid local adaptation in populations of the wheat blast pathogens

ABCDEFGHIJKLMNOPQRSTUVWXYZ

Virulence

group

Seedling reaction

Wheat Oat Isolates

S S S S S S S S S S S 32 16

S S S S S S S S R S S 4 2

S S S S S S S S S S R 2 1

S S S S S S S S R S R 1 0.5

S S S S S S S R S S S 6 3

S S S S S S S S R R S 5 2.5

S S S S S S S R R R S 15 7.5

S S S S S S R R R R R 9 4.5

S S S S S S S S S R S 2 1

S S S S S S S R S R S 3 1.5

S S S S S S S R R S S 2 1

S S S S S S R R R R S 87 43.5

S S S S S S R R R S S 3 1.5

S S S S S S R R S R S 2 1

S S S S S S R R S S S 1 0.5

S S S S S S S S S R R 1 0.5

S S S S S S S R R R R 2 1

S S S R S R R R R R S 1 0.5

S S S R S S R R R R S 1 0.5

S R R R R R R R R R S 6 3

S S S S S S R S S S S 1 0.5

S R R R S R R R R R S 6 3

S R R R S S R R R R S 4 2

S S R S S S R R R R S 1 0.5

S R R S S S R R R R S 1 0.5

R R R R R R R R R R S 2 1

Total 200 100

BRS BuritiBRS 229 Renan BRS 234PFC

2010123

Anahuac

75BR 24

MGS 3

Brilhante

BR 18

TerenaBRS 220 CNT 8 Number Freq. (%)

Emergence of 26 pathotypes that show cultivar specialization and host tissue specialization.



Total 145

N

Frequency distribution of virulence groups (races) in Brazil

Seedling reaction La

titu

de

(S

- N

)

Longitude (W - S)

0 200 400 kmUruguay

Argentina

Paraguay

Bolivia

South America

Atlantic Ocean

Brazil

-

30° -

25° -2

0° -

15

° -1

0° -5

°

0°

-70° -65° -60° -55° -50° -45° -40°

-35°


Total 145

MS = 38

RS = 15

MG = 22

SP = 5

DF_GO = 36

!"

Pyricularia pathotype Triticum (P-T)Pyricularia graminis-tritic(Pgt)

PR = 29 N


Lower “race” diversity based on ear reaction.

Race A and C are virulent on all wheat + oat cultvars.


ABCD

AABBCCDDEET

Virulence group

Ear reactionWheat Oat Isolates

S S S S S S S S S S S 162 80.6S S S S S S S S R S S 27 13.4S S S S S S S S S S R 2 1.0S S S S S S S S R S R 3 1.5S R S S S S S S S S S 2 1.0S R S S S S S R R S S 1 0.5S S S S S S S S R R R 1 0.5S S R S S R S S R R R 1 0.5S S R R R S R R R R S 1 0.5S R R R R R R R R R S 1 0.5

Total 201 100.0

Anahuac 75

BR 24 MGS 3 Brilhante

BR 18 Terena

BRS 220 CNT 8 BRS 229 BRS Buriti Renan BRS 234 PFC 2010123

Number Freq. (%)

Source: Cristina Boaretto, Anderson Danelli, João L. Nunes Maciel / Maciel et al. 2014. Phytopathology 104:95-107


La

titu

de

(S

- N

)

Longitude (W - S)

0 200 400 kmUruguay

Argentina

Paraguay

Bolivia

South America

Atlantic Ocean

Brazil

-

30° -

25° -2

0° -

15

° -1

0° -5

°

0°

-70° -65° -60° -55° -50° -45° -40°

-35°


Total 145

MS = 38

RS = 15

MG = 22

SP = 5

DF_GO = 36

PyrpatTriPyrgra(Pg

!"

Pyricularia oryzae pathotype Triticum (Po-T)Pyricularia graminis-tritici (Pgt)

PR = 29 N


Ear reaction


Total 145

N Frequency distribution of virulence groups (races) in Brazil

Emergence of 10 pathotypes that show cultivar specialization and host tissue specialization

Can we correlate diversity of “avirulence” genes with phenotypic diversity for virulence?

MS PR RS SP MS PR Rice

Mato Grosso do Sul

MS

Minas GeraisMG

GoiásGO

São PauloSP

ParanáPR

Rio Grande do Sul

RS

Distrito Federal

DF

BRASIL

Haplotype network and distribution of AVR1-CO39*

126 isolates

H1Other poaceous hosts (PR and MS)

Triticum (DF)GO

MSMGSPPR

RS

2005N

105

11

1

8

H2 Other poaceous hosts (PR and MS)Triticum (MG)

MSRS

2005

H3 Triticum (PR)

H5Triticum (2005)

Other poaceous hosts (MS)Triticum (GO)

MS

MGSP

RS

H4

* Haplotypes network were constructed by statistical parsimony with the program TCS 1.21 (Clement et 2000. Mol. Ecol. 6:1657-1659).

Haplotypes are connected by line segments representing a single mutational step each.

The unshaded squares represent unsampled haplotypes.

Mutations (sites) 59122222223 78902336692 463366791HaplotypesH1 CTAGAGGATACH2 .....T.....H3 ....GT...G.H4 GCTA..AGA..H5 ..........T

Total: 330 bp

Pgt 76.9 %PoT 54.7 %

Pgt -PoT 25.0 %

Pgt -PoT 1,6 %

Pgt 7.7 %PoT 4.7%

Pgt - %PoT 1.6 %

Major Interpretations 5

Since its emergence the wheat blast pathogens have evolved rapidly to become resistant to QoI and azole fungicides and specialized to include at least 10 pathotypes (26 based on seedling reaction!)

Summary (if there is time left!) Blast disease on wheat and other invasive Poaceae hosts from the Brazilian agroecosystem is caused by multiple Pyricularia species. Pyricularia graminis-tritici and P. oryzae pathotype Triticum are wheat pathogens that likely emerged de novo in Brazil ~30 years ago Pyricularia graminis-tritici did not emerge through adaptive evolution from the rice blast pathogen. Pyricularia oryzae pathotype Triticum may have emerged from an ancestor Pyricularia graminis-tritici population. Several grasses, but mainly Urochloa, may be the preferred host of Pyricularia graminis-tritici, a place for sexual recombination and a reservoir of sexual and asexual inoculum (new focus for control efforts?) Pyricularia graminis-tritici and P. oryzae pathotype Triticum appear to have a high evolutionary potential and poses a risk of becoming an invasive pathogen on wheat crops on other continents

43!!

Funding institutions and grants in Brazil CNPq - Brazilian National Research Council, PPq grant 307361/2012-8 EMBRAPA / Monsanto Research Macro-program FAPESP - São Paulo State Foundation for Research Advancement, grants 2013/10655-4 and 2015/10453-8 Research scientists sponsored in Brazil: Dr. João Maciel (PI/Embrapa Monsanto Research Macroprogram’s grant) Dr. Paulo Ceresini (PI/CNPq and FAPESP’s grants) Dr. Ana Lídia Bonato (EMBRAPA Wheat) Post-Docs: Dr. Vanina Castroagudin (UNESP), CNPq/PDJ grant 150490/2013-5 and FAPESP/PD grant 2014/25904-2 Dr. Giselle Carvalho (UNESP), CAPES/PNPD grant Students: Juliana Reges (PhD/UNESP), Samanta de Oliveira, Nadia Poloni and Danilo Pereira (MSc/UNESP), Adriano Dorigan (undergrad/UNESP): scholarships from CAPES, CNPq or FAPESP.

Acknowledgements

ceresini florianopolis iiwbw_2016_recent_a

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