Barberry panel

The Barberry Connection:Looking for the source of pathogen variability in stem and stripe rustsPanel discussion, BGRI Technical WorkshopMonday, September 3, 2012 (9:00-10:30 AM)

The Barberry Connection:Looking for the source of pathogen variability in stem and stripe rustsPanel discussion, BGRI Technical WorkshopMonday, September 3, 2012 (9:00-10:30 AM)

Barberry eradication laws1600’s Ronen, France

1726-1766 New England coloniesCT, MA, RI

1800’s Many European countriesDenmark, England, France,Germany, etc.

Stakman EC (1918) “The Black Stem Rust and the Barberry.” Yearbook of USDA – 1918, pages 75-100.

Barberry eradication, USA1918-1975

Roelfs AP (1982) Plant Disease 66:177-181

>100,000,000barberry bushes

destroyed

1. Delayed onset of disease2. Reduced virulent inoculum in the spring3. Decreased number of pathogenic races4. Stabilized pathogenic races (e.g. QCC)

Durability of deployed genetic resistance

Known global hot-spots for the recent emergence of new races:Areas without a history of systematic alternate host surveillance and control

Endemic barberries are found on every continent, except AustraliaNearly 500 barberry species, with high diversity in South America, Africa, and Asia

1. What is the distribution of alternate hosts, relative to wheat production?

Y. Jin, USA

A. Berlin, Sweden

ZS Kang, PR China

R. Wanyera, Kenya

W. Getaneh, Ethiopia

E. Skolotneva, Russian Fed.

K. Nazari, ICARDA

Do alternate hosts undermine our efforts to achieve durable resistance?

2. What role, if any, do these species play in rust epidemiology today?

THE BARBERRY STORY IN KENYA

Ruth Wanyera

Kenya Agricultural Research Institute (KARI), Njoro

Email:wanyera@plantprotection.co.ke

TTKSF

UG99 PRESENT STATUS

The rapid emergence of Ug99 derivative races (a "stacking" of virulences first Sr31, then Sr24, then Sr36, etc.) suggests that sexual recombination may play a role in the evolution of Pgt virulence in East Africa

LLL

Life cycle of stem rust

1. Are there barberries in East Africa?2. Are they susceptible to cereal rusts?3. Do they function as alternate hosts under natural

conditions?

Records at the Kenya National museum showed the presence of Berberis holstii Engl., in East Africa

Barberry hunting and aecia collection since 2008

Njoro Area

Mau-Narok

Mt. Kenya

Olkalau/Nyahururu

Narok

Meru (Chogoria Forest)

Mt. Elgon (Kenya Side)

Barberry surveyed sites• Aecia positively identified in the lab

Barberry hunting…

The barberry plant is medicinal, fruits are eaten by children

Locating barberry stands required coordination of the local communities and experts outside the wheat rust community

Dug up barberry bush

Inoculation process initiated in the greenhouse at Njoro to determine if the aeciospores produced on the barberry leaves are wheat rusts, proved unsuccessful (environmental conditions?).

KARI Muguga South (away from wheat growing areas and barberry sites), but no sporulation was observed ( unfavorable conditions?)

Inoculations

Inoculations

Efforts made trying to get aeciospores from Kenya to the CDL for analysis, proved unsuccessful because of viability issues

Way forward

Need resources to conduct molecular diagnostics locally

In country capacity building to isolate and identify Pgt from alternate hosts, due to fragility of aeciospores relative to urediniospores

THANK YOU

Aecial Infections on Barberry Plants (Zinkila) in Ethiopia

W. Getaneh, EIAR - AmboBeijing, China

September 2012

Introduction

• Around 1958, barberry (B. holstii) plant surveys were conducted by the Biology Department of Addis Ababa University in the northern part of Ethiopia.

• In 1978, the Plant Protection Research Center (PRCC) conducted barberry surveys in the north Shewa zone; collected aeciospores were inoculated on wheat seedlings, but no infection was observed.

Introduction

In 2009, the pathology section of the PPRC conducted B. holstii surveys to investigate whether the plant functions as an alternate host to stem rust in Ethiopia.

These surveys were carried out in the northern part of Ethiopia (Shewa zone).

Surveys

• In the north Shewa zone, 5 locations were identified where B. holstii grows

• These locations range in altitude from 2781- 2895 m

• Abundant aeciospores were found on barberry leaves from September to January.

Surveys

Aeciospores on B. holstii leaves

Greenhouse Inoculation

Collected aeciospores were inoculated on the following species identification set:

Genotype SpeciesMcNair 701 WheatLine E WheatMorocco WheatLemhi WheatSr31/6*LMPG WheatProlific RyeWinter rye RyeHiproly BarleyHypana BarleyOtana Oat

Greenhouse Inoculation

Greenhouse Inoculation

Greenhouse Inoculation

Greenhouse Inoculation

Inoculation results

From 6 inoculations, we obtained:Infection

Genotype Species (# pustules)McNair 701 Wheat 0Line E Wheat 1Morocco Wheat 0Lemhi Wheat 0Sr31/6*LMPG Wheat fewProlific Rye manyWinter rye Rye manyHiproly Barley manyHypana Barley manyOtana Oat 0

*

* Confirmed in US lab by both inoculation and DNA analysis

Conclusion

Our results suggest that B. holstii functions as an alternate host to stem rusts of cereals in Ethiopia, but this result is preliminary and will require confirmation and further study.

Acknowledgements

I wish to acknowledge BGRI/DRRW project for financing this activity and giving me the opportunity to participate in this Technical Workshop.

Inoculation materials and research support were generously provided by CDL.

Ekaterina S. Skolotneva

Moscow Lomonosov State University

All-Russian Research Institute of Phytopathology

Surveying aecial infections on Berberis spp.in Central Russia

..........

......

. Sampling locations

Barberry survey in the Central Region of Russia (2000-2009)

B. vulgaris

B. purpurea

• Are there any Berberis spp. in the region?

• Yes.

Barberry bushes

Barberry bushes

Golicyno-city

Field of wheat crops

B. vulgaris

B. purpurea

Dates of disease development in Central Russia

B. vulgaris

August, 2012: winter wheat Nemchinovskaya 24 Agropyron repens

August

Othermonths

May

July

June

• We consider a location of bushes as a sample. It may be single bush or group of bushes which are the same species and next to each other

• Only fresh aeciospores are collected for inoculation

• From aecial samples we isolate different formae specialis of Puccinia graminis: P. graminis f. sp. secalis

P. graminis f. sp. avenae P. graminis f. sp. tritici

Sampling strategy from barberries

Susceptible alternate hosts to stem rust: B. vulgaris and B. purpurea.

Identification of Pgt races

B. vulgaris

• The International Set of 20 wheat differential lines was used (upgraded in 2006, Prof. Yue Jin, USDA-ARS Cereal Disease Laboratory, University of Minnesota, USA)

• From 2000 to 2009 twenty different Pgt races were isolated from barberry

The frequencies of Pgt races isolated from barberry

Summary

Barberry species distributed in the Central region of Russia were shown to serve as alternate hosts for stem rust pathogens under natural conditions

A diversity of stem rust races was isolated from these species.

Alternate hosts panel discussion-P. graminis in the presence of barberry Anna Berlin

Background & law of barberry eradication

•The Swedish law of barberry eradication was repealed in 1994

•There is no formal survey regarding presence of barberry

100kmwww.artportalen.se

Reported barberry2000-2012

Stockholm

Jan Feb Mar Apr May Jun Jul Aug Sept Oct Nov Dec

planting

planting

Harvest spring cereals

Harvestfall-sowncereals

Markers enable connecting populations from the two hosts

Berlin et al. 2012 Phytopathology

K=6 data from one structure run

Diversity

•30 samples = 30 genotypes

•30 genotypes = ? Races

X X X

X X X

X X X

X X X

X X X

X X X

X X X

X X X

X X X

X X X10

0 m

30 m

Why no stem rust on wheat?• Barberry present

• Severe epidemics on oats and natural grasses

• Some rust on rye

• Large genotypic variation within and between fields

• P. graminis clearly completing its sexual cycle

• Does the population identified as P. graminis f. sp. tritici/secalis lack the virulence necessary to infect wheat?

• Does wheat grown in Sweden have effective resistance genes?

Research progress on alternate host and sexual stage of wheat stripe rust in

China

Zhensheng KangState Key Laboratory of Crop Stress Biology for Arid Areas, Northwest A & F University,Yangling, Shaanxi,

China

Wheat stripe rust (Pst) is a destructive disease throughout all winter wheat regions in China and is considered the most important disease of wheat.

Diseased area: between 3-6 million ha. Yield losses: 10-50%.

Years Losses (million tonnes) 1950 6.0 1964 3.2 1990 2.6 2002 1.4

Western over-summering areas

Over-wintering areas

Eastern epidemic areas

Based on historical epidemiological data for stripe rust, the wheat-growing regions in China can be divided into three areas:

Over-summering areasOver-wintering areasEastern epidemic areas

In the mountainous western areas, stripe rust can over-summer on volunteer wheat and late-maturing spring wheat.

Over-summering areas in south GuansuVolunteer wheat in south Guansu

oversummermovementThe migration pathway of P. striiformis in China.

Gansu

Sichuan

Shaanxi

Shanxi

Hebei

Shandong

Henan

Hubei

Ningxia

Chongqing

Anhui

Jiansu

Most new races were first detected in these regions in recent history;

A high genetic diversity within the regions’ Pst populations has been reported by different research groups (Lu et al., 2011; Duan et al., 2010; Mboup et al., 2009);

The genetic recombination was found to occur for Pst in these regions (Lu et al.,2011; Duan et al., 2010; Mboup et al., 2009).

The western over-summering areas are considered a “hot-spot” for the emergence of new races of wheat stripe rust in China.

Virulence variation for rusts maybe due to

sexual hybridizationmutationssomatic hybridization

However, the mechanism of sexual hybridization for wheat stripe rust has been neglected since the sexual stage was presumed to be absent.

Why does the western over-summering areas become the “hot-spot” for wheat stripe rust in China?

In 2010, some Berberis spp. were shown to serve as alternate hosts for the wheat stripe rust pathogen. B. chinensis, B. holstii, B. koreana B. vulgaris.

Questions: Does the sexual stage of wheat stripe rust occur under natural conditions, particularly in China?

Do any susceptible barberry species coexist with wheat in China?

Can wheat stripe rust be isolated from infected Berberis spp. in China?

Does the sexual stage of wheat stripe rust contribute to variation in virulence?

Surveys for Berberis spp.in China

215 of the ~500 described Berberis spp. in the world are endemic to China;

Many of China's Berberis spp. are distributed in the western over-summering areas (hot-spot).

Western China: Sichuan ： 81; Chongqin ： 30; Yunnan ： 78; Tibet: 55; Guansu ： 26; Shaanxi: 20; Guizhou ： 19; Qinghai ： 13; Xinjiang ： 5; Ningxia ： 3;

Central China: Hubei ： 24; Henan ： 7; Shanxi ： 10; Hunan ： 9; Anhui ： 2;

Eastern China: Hebei ： 6; Jiangxi ： 5; Guandong ： 4; Guanxi ： 4; Hujian ： 5;

Distribution of Berberis species in different regions of China

B. brachypodaB. shensiana

Berberis soulieana B. potaninii

Are these Berberis spp. susceptible to wheat stripe rust ?

Identification of Berberis spp. as alternate hosts of wheat stripe rust

Dew chamber

We collected seeds and seedlings of Berberis spp. from the field and inoculated using telia of Pst in the greenhouse.

Normally, we see pycnia on the leaves of susceptible Berberis spp. 11-14 days after inoculation.

Infection of basidiospore and development of pycnia

Pycnia on Berberis

Identification of Berberis spp. as alternate hosts of wheat stripe rust

Identification of Berberis spp. as alternate hosts of wheat stripe rust

About 20 days after inoculation, we see aecia develop on the leaves. Aeciospores can infect wheat through the stoma and produce typical rust symptoms (uredinia).

No. Berberis spp. Orgin Distribution

1 B. aggregata Gansu, China

Gansu, Sichuan, Hubei, Qinghai, Shanxi

2 B. brachypoda Gansu, China

Gansu, Sichuan, Hubei, Qinghai, Shanxi,Henan, Shanxi

3 B. potaninii Gansu, China

Gansu, Shaanxi, Sichuan

4 B. soulieana Gansu, China

Gansu, Shaanxi, Sichuan,Hubei

5 B. dasystachya Shaanxi, China

Gansu, Shaanxi,Hubei,Shanxi

6 B. shensiana Shaanxi, China

Shaanxi,Gansu

7 B. atrocarpa Sichuan, China

Sichuan, Yunnan, Hunan

8 B ． ferdinandi-coburgii

Yunnan, China

Yunnan

9 B. phanera Yunnan, China

Yunna, Sichuan

10 B. aggregate var. integrifolia

Yunnan, China

Gansu, Sichuan,Qinghai,Hubei,Shanxi

11 B. davidii Yunnan, China

Yunnan

12 B. stenostachya Gansu, China

Gansu, Shaanxi, Shanxi

13 B. wangii Yunnan, China

Yunnan

14 B. circumserrata Shaanxi, China

Shaanxi, Hubei, Gansu, Qinghai,Henan

15 B. poiretii Beijing, China

Shaanxi, Qinghai, shanxi, Hebei, Jilin, Liaoning,

16 B. guizhouensis Guizhou, China

Guizhou

Species of barberry identified as alternate hosts of Pst by artificial inoculation, using germinating teliospores in China

Some species are evergreen, distributed in southwest regions. Others are deciduous, distributed in northwest regions. Some susceptible species (e.g., Berberis soulieana, B. brachypoda, and B. shensiana) are widely distributed in the western over- summering areas.

Berberis soulieana

B. shensiana

Are any Berberis spp. infected by wheat stripe rust under natural conditions in

China?

Aecia produced on barberry leaves in nature

We collected 3703 infected- barberry leaves in the fields and inoculated wheat with aeciospores in the greenhouse.

Four stripe rust cultures (B2011-1, B2011-2, B2011-3, and B2011-4) from three barberry (Berberis spp.) species including B. brachypoda , B. soulieana , and B. shensiana collected from Gansu and Shaanxi Provinces in 2011, respectively.

Berberis brachypoda B. Soulieana B. ShensianaB2011-1 B2011-3 B2011-4B2011-2

Berberis species Origin Number of aecium-isolate

Number of uredium-culture produced on wheat Mingxian 169

Berberis brachypoda

Gansu 1519 2

B. shensiana Shaanxi 410 1

B. soulieana Gansu 384 1

B. potaninii Shaanxi 742 0

B. aggregate Gansu 648 0

Are any Berberis spp. infected by wheat stripe rust under natural conditions in

China?

Ethidium bromide(EB) stained agarose gel showing that four isolates B2011-1, 2011-2,2011-3, and 2011-4 from naturally rust-infected barberry species produced uniform single band amplified using primers ITS-puccinia (5'-ACATCGATGAAGAACACAGT-3' )/ITS4( 5'- TCCTCCGCTTATTG-ATATGC-3')(left, part A), and specific-primers PSF(5'-GGATGTTGAGT-GCTGCTGTAA-3' )/PSR (5‘-TTGAGGTCTTAAGGTTAAAA-TTG-3' ) (right, part B) in accord with race CYR 32 of Puccinia striiformis f. sp. tritici as positive control in size. Sterile water used as negative control (NC). M= 100bp DNA marker DL2000.

M

A

M

B

B2011-1

B2011-2

B2011-3

B2011-4

CYR32

NC

MB2011-1

B2011-2

B2011-3

B2011-4

CYR32

NC

Can any Berberis spp. be infected by wheat stripe rust under natural

conditions in China?

PCR tests using two Pst-specific primer pairs demonstrate the recovery of four cultures of Pst from Berberis spp.

Comparison of infection types on Chinese differential hosts of eight major races of Pst and the four Pst cultures recovered from three barberry species

Virulence tests demonstrated that the infection types of the four barberry-derived cultures are different compared to the major Chinese races.

Cultures and

racesOrigin of cultures

Differential hosts

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19

B2011-1 Berberis brachypoda R S R S S S R S R SR S R R S R R R R R

B2011-2 B. brachypoda R S R S S R R S R R S R R R R R R R R

B2011-3 B. shensiana R S R S S R S S R RS S R R RS R R R R R

B2011-4 B. soulieana R S R R S S R S R R R R R S R S R R R

CYR33 Triticum aestivum S S S S S S S S S S S S S S R S R R R

CYR32 T. aestivum S S S S S S S S S S S S S S R S S R R

CYR31 T. aestivum S S S S S S S S S R S S R S R S S R R

CYR30 T. aestivum S S S S S S S S S R S S R R R S S R R

CYR29 T. aestivum S S S S S S S S S R S S R R R S R R R

CYR28 T. aestivum S S S S S S S S S R S R R R R S R R R

CYR23 T. aestivum S S S S R S S S S R S R R R R R R R R

CYR17 T. aestivum SR S R SR R SR S R R R RS R R R R R R R R

Does the sexual stage under natural conditions contribute to variation in virulence for wheat stripe rust in China

→ → →

Aecia from Berberry

Recovered culturefrom aecium

Single-uredium isolates

Virulence test on differentials

Infection type of single-uredium isolates on differential hosts

No. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19

B2011-2 -1 R S R S R R R S R R S R R R R R R R R

B2011-2 -2 R S R R R R R S R R R R R S R R R R R

B2011-2 -3 R S R S R R R S R R S R R R R R R R R

B2011-2 -4 R S R S R R R S R R S R R S R R R R R

B2011-2 -5 R S R R R R R S R R S R R R R R R R R

B2011-2 -6 R S R S R R R S R R R R R R R R R R R

B2011-2 -7 R S R S S R R S R R S R R R R R R R R

Virulence difference among single-uredium isolates from single-aecium-derived culture

(B2011-2) on differentials

The virulence tests showed high diversity in virulence among the single-uredium isolates.

No. Infection type of single-uredium isolates on differential hosts

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19

B2011-1-1 RS S R S R S RS S R R R R R S R S R R R

B2011-1-2 R S R S S S R S R R R R R S R R R R R

B2011-1-3 R R R S S S RS S R RS RS R R S R R R R R

B2011-1-4 R S R S S R R S R S R R R S R R R R R

B2011-1-5 R S R R R S SR SR R R SR R R S R R R R R

B2011-1-6 R S S S R S R S R R S R R S R R R R R

B2011-1-7 R S S S S R R S R S S R R R R R R R R

B2011-1-8 R S R SR SR S RS S R R RS SR R S R R R RS R

B2011-1-9 R S S S S S R S R R RS R R S R R R R R

B2011-1-10 R S R S SR S R S R SR SR R R S R R R R RS

B2011-1-11 R S S S R S R S R S R R R S R R R R R

B2011-1-12 R S R S SR SR R S R R S R R RS R R R R R

B2011-1-13 R S S S S S R S R S R R R S R R R R R

B2011-1-14 R S R R R S RS S R RS R R R R R R R R R

B2011-1-15 R S R S SR S R S R R RS RS R S R R R R R

B2011-1-16 R S R S R S R S R RS RS RS R S R RS R R R

B2011-1-17 R S S S S S R S R S R R R S R R R R R

B2011-1-18 R S R S S S RS S R SR R R R S R R RS R R

B2011-1-19 R S R R RS S R S R R RS R R R R R R R R

B2011-1-20 R S R S S S R S R SR RS R R RS R R R R R

B2011-1-21 R S R S S S R S R SR S R R S R R R R R

B2011-1-22 R S R S S S R S R SR S R R S R R R R R

Virulence difference among single-uredium isolates from single-aecium-derived culture (B2011-1) on differentials

So far, 16 of the 22 tested barberry species from over-summering areas show susceptibility to wheat stripe rust, indicating that there is a great diversity of potential alternate hosts for stripe rust in China.

Four cultures of wheat stripe rust were obtained from three barberry species in the field, indicating that the sexual stage of wheat stripe rust occurs under natural conditions in China.

Virulence tests for single-uredium isolates recovered from a single aecium demonstrate that the sexual stage contributes to variation in virulence for the wheat stripe rust pathogen in China.

Summary

Future Work

More barberry species need to be tested for their susceptibility to Pst in China;

More field Surveys need to be conducted;

More evidence is needed to elucidate the relationship between genetic diversity and

the sexual stage of Pst,

The earmarked fund for Modern Agro-industry Technology Research System in China

National Basic Research Program of China (973)

Nature Science Foundation of China

The 111 Project from the Chinese Ministry of Education

Acknowledgement

Dr. Jie Zhao, Prof. Lili Huang, Dr. Hongchang Zhang, Dr. Dejun Han, Dr. Xiaojie Wang, Dr. Chunfang Wang,Dr. Qingmei Han, Dr. Jun Gou, Mrs. Guorong Wei, Dr. Xueling Huang, Dr. Gang Zhang, Dr. Yonghong Zhang,Dr. Xiumei Yu, Dr. Changqing Chen, Dr. Liangsheng Xu, Dr. Ninghai Lu,Dr. Bo Liu, Dr. Jingbiao Ma, Mr. Gangming Zhan, Dr. Wenming zheng All Ph D and Master studendts in My Lab.

Dr. X M. Chen, Dr. H. Buchenauer, Dr. Robert McIntosh , Dr. Colin Wellings, Dr. Scot H. Hulbert, Dr. Jin-Rong Xu, Dr. Shiping Wang, Dr. Hei Leung, Dr. J. ChongDr. Yue Jin, Dr. Ravi Singh, Dr. Zacharias Pretorius

Thanks for your attention!

Looking for the Source of Pathogen Variability in Stem and Stripe Rusts – the

Barberry Connection

Kumarse NazariICARDA

September 2012

2012 BGRI Technical WorkshopAlternate Hosts Panel Discussion

Berberis rust survey in the Ug99 pathway in CWANA

Kumarse Nazari ICARDA

Annemarie F. Justesen GRRC, Aarhus University

Jens Grønbech Hansen GRRC, Aarhus University

Dave Hodson CIMMYT

Mehran Patpour, Farzad Afshari, Seed and Plant Improvement Institute, Karaj Iran

Hojjatollah Rabbani Nasab North Khorassan Agricultural and Natural Resource

Zoia Sikharulidze Institute of Plant Immunity from Georgia

Amir Amanov, Zafar Ziyaev Kashkadarya Grain Breeding and Seed Production Institute, Uzbekistan

Atiq ur Rehman Rattu National Agricultural Research Centre, Pakistan

Hukmatullo Ahmadov, Mahbubjon Rahmatovm, Bahiram Tajik Academy of Agricultural Sciences

Konul Aslanova Agrarian and Animal Husbandry Research Institute, Azerbaijan

•Berberis survey and biological assays

•Photo documentation of the Berberis host

•Leaf sample collection of Berberis spp.

•DNA-extraction from single aecial pustules, several pustules from each barberry plant

•PCR amplification of EF1α- and/or β-tub-gene

•Species identification by sequence comparisons to sequences in GenBank and reference sequences from grass and cereal hosts

Methodology

DNA sequence data obtained so far:

•Iran: 12 sequences (2010), 4 (2012)

•Tajikistan : 24 sequences (2011)

•Uzbekistan: 7 sequences (2012)

•Azerbaijan : 6 sequences (2012)

Kelardasht N 36.5002- E 51.1683- H 1224

No. Name /Line Gene Z.STOL

Z.KELMP-SP.

TP 1 ZERESHK KEL89 ZER 88 ZER89 TP3-

3ZERESHK 89

TP3ZERESHK 89-

TP2

1 ISr5-Ra Sr5 33+ 3 4 4 4 33+ 4

2 CnS_T_mono_deriv Sr21 33+ 3 4 4 4 12+ 4

3 Vernsatine Sr9e 2+3 3 4 4 4 3+ 4

4 ISr7b-Ra Sr7b 4 3 4 4 4 3+ 4

5 ISr11-Ra Sr11 4 4 4 4 ;1 4 ;C11-

6 ISr6-Ra Sr6 4 4 4 4 4 3+ 33+

7 ISr8a-Ra Sr8a 4 4 4 4 4 3+ 33+

8 CnSr9g Sr9g 4 3+ 4 4 4 33+ 3+

9 W2691SrTt-1 Sr36 4 3 4 4 33+ 33+ 4

10 W2691Sr9b Sr9b 4 33+ 4 4 4 3+ 4

11 BtSr30Wst Sr30 4 33+ 4 4 4 3+ 4

12 Combination VII Sr17 3+ ;1 4 3+ 4 3+ 4

13 ISr9a-Ra Sr9a 4 3+ 4 4 4 3/33+ 3+

14 ISr9d-Ra Sr9d 4 3 4 4 4 3/33+ 3+

15 W2691Sr10 Sr10 4 3 4 4 4 3+ 3+

16 CnsSrTmp SrTmp 33+ 2- 4 4 4 ;C1= 3+

17 LcSr24Ag Sr24 ;1 ;1- 11-C 1+2-C ; ;C 1-

18 Sr31/6*LMPG Sr31 ; 3+ 0;1= 1C ;1 ;C1- ;C1=

19 Trident Sr38 X+ 4 ;C1= 3+ 3x X- ;;CN

20 McNair 701 SrMcN 4 4 4 4 4 3+ 33+

Race Identified TTTTF TTSSK TTTTC TTTTF TKTTF PTTSC TKTTC

Preliminary results

• Two main clusters: P. graminis and P. striiformis

•Within the P. graminis cluster, sequences show 94-95% identity to Pgt sequences in GenBank

•All sequences within the P. striiformis cluster are from Tajikistan and show 99-100% identity to P. striiformis f.sp. dactylis (P. striiformoides), none are identical to P. striiformis f.sp. tritici

Future work

Continue sequencing of more aecia

Sequence β-tubulin or ITS in order to be able to identify host origin based on sequences in GenBank

Obtain more reference sequences from grasses??

Looking for the Source of Pathogen Variability in Stem and Stripe Rusts—the Barberry Connection

--- Knowledge Gaps and Challenges

Yue Jin

USDA-ARS Cereal Disease LaboratoryUniversity of Minnesota, St Paul, Minnesota, USA

“Cereal rusts are the most-researched plant diseases”

“A large body of literature exists”

“Cereal rusts are the most-researched plant diseases”

“A large body of literature exists”

Interpretation: there are no more mysteries!

Puccinia graminis from Mahonia spp.

“Does barberry play a role in pathogen variation and disease epidemiology in stem rust and stripe rust?”

e.g. the Kenya example:

Are there barberries? ----- Yes (B. holstii)

Is B. holstii susceptible to stem rust? ----- Yes

Does B. holstii function as an alternate host in Kenya?----- Do not know

“What is the species?”

Is there any taxonomic support when we encounter unknown species?

Can we develop a robust assay to identify Berberis spp.?

Barberry is back.

Please remain skeptical!

The Barberry Connection:Looking for the source of pathogen variability in stem and stripe rusts

The Barberry Connection:Looking for the source of pathogen variability in stem and stripe rusts

2000 2004 2008 2012

Sounding the AlarmGlobal Rust Initiative (GRI)

1. Race surveillance2. Resistance screening3. Breeding4. Chemical control5. Seed production6. Impact assessment7. Training8. Infrastructure (E. Africa)9. Reporting and communication10. Resources for IARCs

Sr31 virulencedetected in Uganda(Ug99)

Sr31 + Sr24 (Kenya)

Sr31 + Sr36 (Kenya)

UgandaEthiopia

Kenya TanzaniaZimbabwe

EritreaIran S. AfricaSudanYemen

Ug99races

2000 2004 2008 2012

Sounding the Alarm

Sr31 virulencedetected in Uganda(Ug99)

Sr31 + Sr24 (Kenya)

Sr31 + Sr36 (Kenya)

UgandaEthiopia

Kenya TanzaniaZimbabwe

EritreaIran S. AfricaSudanYemen

Ug99races

East African nativebarberry (B. holstii)

shown to be susceptibleto stem rust

Aecial infections onB. holstii found in

East Africa

Barberry spp. shownto function as alternatehosts to wheat stripe rust

Sexual populations ofwheat stripe rust foundin China

B. holstii shown to be susceptible to stripe rust

Sexual populations ofwheat stem rust found on

Mahonia spp. in PNW

Sexual populations ofoat stem rust found

in Sweden

Training video: barberry.globalrust.org

The Barberry Connection:Looking for the source of pathogen variability in stem and stripe rusts

The Barberry Connection:Looking for the source of pathogen variability in stem and stripe rusts

A Berlin, Sweden Y Jin, USAZS Kang, ChinaK Nazari, ICARDA, SyriaE Skolotneva, Russian FederationR Wanyera, KARI, KenyaG Woldeab, EIAR, Ethiopia

A Berlin, Sweden Y Jin, USAZS Kang, ChinaK Nazari, ICARDA, SyriaE Skolotneva, Russian FederationR Wanyera, KARI, KenyaG Woldeab, EIAR, Ethiopia