New evidence supporting the occurrence of
sexual reproduction in the wheat stripe
rust fungus on barberry in China
Zhenshe...
Wheat stripe rust is a destructive disease
throughout all winter wheat regions in China
and is considered the most importa...
Western over-summering areas
Over-wintering areas
Eastern epidemic areas
Based on historical epidemiological data for stri...
In the western mountainous areas, stripe rust can over-
summer on volunteer wheat and late-maturing spring wheat.
Terrace ...
Migration pathway of Pst in China
Shandong
Jiansu
Anhui
Hubei
Henan
Shaanxi
Gansu
Shanxi
Sichuan
Qinghai
Hebei
Ningxia Eas...
Ø  The most new races (≈90%) were first detected in
these regions in recent history of surveillance;
Ø  A high genetic d...
Virulence variation for rusts maybe due to
Ø sexual hybridization
Ø mutations
Ø somatic hybridization
However, the mech...
In 2010, some Berberis spp. were shown to serve as
alternate hosts for the wheat stripe rust pathogen.
Ø  B. chinensis,
Ø...
Question: Does the sexual stage of
wheat stripe rust occur under natural
conditions, particularly in China?
Ø Is there an...
Surveys for Berberis spp.in China
Ø  215 of the ~500 described Berberis spp. in the world
are endemic to China;
Ø  Many ...
Surveys for Berberis spp.in China
No barberry plant
Barberry plants distributed
Barberry plants with rusts
30 barberry species were surveyed and
identified....
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 Be...
Identification of Berberis spp.
as alternate hosts of wheat stripe rust
Normally, we see pycnia on the leaves of susceptib...
Identification of Berberis spp.
as alternate hosts of wheat stripe rust
About 20 days after inoculation, we see aecia deve...
23 Berberis species: alternate host for Pst
Successful production of pycnia, and aecia on
upper and back sides of barberry...
A B C D E F
G H I J K L
M N O P Q R
Zhao, J., et al. Phytopathology, 2013, 103(9):927-934
No. Berberis spp. Orgin Distribution
1 B. aggregata Gansu, China Gansu, Sichuan, Hubei, Qinghai, Shanxi
2 B. brachypoda Ga...
Ø  Some species are evergreen, distributed in southwest regions.
Ø  Others are deciduous, distributed in northwest regio...
Can barberry species be infected by the
stripe rust fungus (Pst) in nature?
It is very common to see pycnia and aecia on
i...
Obtaining of Pst isolates from rust-
infected barberry growing in nature
20 Pst isolates recovered from the infected barbe...
Berberis spp. No. of aecia
No. of isolate Rate (%)
IT0 IT1-2 Pst Pgt Pst Pgt
B. brachypoda 1519 479 1032 2 6 0.13 0.39
B. ...
Comparison of infection types on Chinese differential
hosts of eight major races of Pst and the four Pst
isolates recovere...
Berberis spp. No. of aecia
Number of isolate* Rate (%)
IT 0 IT 1-2 Pst Pgt Pst Pgt
B. shensiana 3677 3630 40 4 3 0.11 0.08...
Berberis
(origin)
Isolate
No.
Chinese differential hosts for Pst
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19
20
(ck)
R...
Single Aecia
from barberry
Recovered isolate
from single aecium
Single uredium
(Su) isolates
Virulence test on
NILs
Does t...
Virulence patterns of single-uredium isolates
from recovered Pst isolate on near-isogenic lines
SU isolate
Yr NILs
1 2 3 4...
SU
isolate
Yr NILs
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19
Yr2 Yr5 Yr6 Yr7 Yr8 Yr9 Yr10 Yr15 Yr17 Yr24 Yr26 Yr27 Y...
Single Aecia
from barberry
Recovered isolate
from single aecium
Single uredium
(Su) isolates
Virulence test on
NILs
Does t...
Ø  23 of the 30 tested barberry species show susceptibility to Pst,
indicating that there is a great diversity of potenti...
Ø  The earmarked fund for
Modern Agro-industry
Technology Research System in
China
Ø  National Basic Research
Program of...
Thanks for your attention!
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New evidence supporting the occurrence of sexual reproduction in the wheat stripe rust fungus on barberry in China

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Zhensheng Kang, Northwest A&F University, China

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New evidence supporting the occurrence of sexual reproduction in the wheat stripe rust fungus on barberry in China

  1. 1. New evidence supporting the occurrence of sexual reproduction in the wheat stripe rust fungus on barberry in China Zhensheng Kang State Key Laboratory of Crop Stress Biology for Arid Areas, Northwest A & F University,Yangling, Shaanxi, China
  2. 2. Wheat stripe rust is a destructive disease throughout all winter wheat regions in China and is considered the most important disease of wheat. Ø  Diseased area: between 3-6 million ha. Ø  Yield losses: 10-50%. Years Losses (million tonnes) 1950 6.0 1964 3.2 1990 2.6 2002 1.4
  3. 3. 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: Epidemics of Pst in China
  4. 4. In the western mountainous areas, stripe rust can over- summer on volunteer wheat and late-maturing spring wheat. Terrace lands for growing wheat in Over-summering areas in south Guansu Diseased volunteer wheat in south Guansu Pst survival in over-summering areas in China
  5. 5. Migration pathway of Pst in China Shandong Jiansu Anhui Hubei Henan Shaanxi Gansu Shanxi Sichuan Qinghai Hebei Ningxia Eastern epidemic areas Infecting autumn sown wheat
  6. 6. Ø  The most new races (≈90%) were first detected in these regions in recent history of surveillance; Ø  A high genetic diversity within the regional Pst populations has been reported by different research groups (Lu et al., 2011; Duan et al., 2010; Mboup et al., 2009); Ø  The genetic recombination for Pst was found in these regions (Lu et al.,2011; Duan et al., 2010; Mboup et al., 2009). The western over-summering areas has been caught much national and international attentions, and are considered as a “hot-spot” for Pst.
  7. 7. Virulence variation for rusts maybe due to Ø sexual hybridization Ø mutations Ø somatic hybridization However, the mechanism of sexual hybridization for Pst has been neglected since the sexual stage was presumed to be absent. Why does the western over-summering areas become the “hot-spot” for Pst in China?
  8. 8. In 2010, some Berberis spp. were shown to serve as alternate hosts for the wheat stripe rust pathogen. Ø  B. chinensis, Ø  B. holstii, Ø  B. koreana Ø  B. vulgaris.
  9. 9. Question: Does the sexual stage of wheat stripe rust occur under natural conditions, particularly in China? Ø Is there any susceptible barberry species in China? Ø Can wheat stripe rust be isolated from infected Berberis spp.? Ø Does the sexual stage of wheat stripe rust contribute to variation in virulence?  
  10. 10. Surveys for Berberis spp.in China Ø  215 of the ~500 described Berberis spp. in the world are endemic to China; Ø  Many of China's Berberis spp. distribute 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
  11. 11. Surveys for Berberis spp.in China
  12. 12. No barberry plant Barberry plants distributed Barberry plants with rusts 30 barberry species were surveyed and identified. Over-summering area
  13. 13. B. brachypodaB. shensiana Berberis soulieana B. potaninii
  14. 14. Are these Berberis spp. susceptible to wheat stripe rust ?
  15. 15. Identification of Berberis spp. as alternate hosts of wheat stripe rust Dew chamber We collected seeds and seedlings of Berberis spp. from the fields and inoculated using telia of Pst in the greenhouse.
  16. 16. Identification of Berberis spp. as alternate hosts of wheat stripe rust 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
  17. 17. 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).
  18. 18. 23 Berberis species: alternate host for Pst Successful production of pycnia, and aecia on upper and back sides of barberry leaf after inoculation Zhao, J., et al. Phytopathology, 2013, 103(9):927-934
  19. 19. A B C D E F G H I J K L M N O P Q R Zhao, J., et al. Phytopathology, 2013, 103(9):927-934
  20. 20. 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 17 B. wilsonae Yunnan, China Yunnan, Tibet, Shaanxi, Qinghai, Hubei, Guizhou 18 B. sp. (unidentified) Tibet, China Tibet 19 B. jamesiana Yunnan, China Yunnan,Qinghai, Chongqing, Tibet, Sichuan 20 B. coryi Yunnan, China Yunnan 21 B. wilsonae Yunnan, China Yunnan, Sichuan, Tibet, Gansu 22 B. sp. Tibet, China Tibet 23 B. sp. Tibet, China Tibet Species of barberry identified as alternate hosts for Pst by artificial inoculation using germinated teliospores in China
  21. 21. Ø  Some species are evergreen, distributed in southwest regions. Ø  Others are deciduous, distributed in northwest regions. Ø  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
  22. 22. Can barberry species be infected by the stripe rust fungus (Pst) in nature? It is very common to see pycnia and aecia on infected Berberis leaves in fields in early May.
  23. 23. Obtaining of Pst isolates from rust- infected barberry growing in nature 20 Pst isolates recovered from the infected barberry Ø  4 Pst isolated from 3 barberry species in 2011 Ø  16 Pst isolates from 3 barberry species in 2013 collected the infected Berberis leaves Single aecium (SA) was used for inoculation Recovered SA isolate on wheat leaf
  24. 24. Berberis spp. No. of aecia No. of isolate Rate (%) IT0 IT1-2 Pst Pgt Pst Pgt B. brachypoda 1519 479 1032 2 6 0.13 0.39 B. shensiana 410 35 374 1 0 0.24 0.00 B. soulieana 384 367 16 1 0 0.26 0.00 B. potaninii 742 711 28 0 3 0.00 0.40 B. aggregata 648 633 13 0 2 0.00 0.31 Total 3703 2225 1463 4 11 0.11 0.30 Pst isolates recovered from rust-infected Berberis spp. in Gansu, and Shaanxi in 2011 *IT0 indicates no any necrosis, or/and chlorosis on wheat after inoculation, IT1-2 indicates necrosis, or/and chlorosis; Pst=Puccinia striiformis f. sp. tritici; Pgt=Puccinia graminis f. sp. tritici
  25. 25. Comparison of infection types on Chinese differential hosts of eight major races of Pst and the four Pst isolates recovered from three barberry species in 2011 Virulence tests demonstrated that the infection types of the four barberry-recovered cultures are different compared to the major Chinese races. Cultures and races Origin 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 A V A V V V A V A VA V A A V A A A A A B2011-2 B. brachypoda A V A V V A A V A A V A A A A A A A A B2011-3 B. shensiana A V A V V A V V A AV V A A AV A A A A A B2011-4 B. soulieana A V A A V V A V A A A A A V A V A A A CYA33 Triticum aestivum V V V V V V V V V V V V V V A V A A A CYA32 T. aestivum V V V V V V V V V V V V V V A V V A A CYA31 T. aestivum V V V V V V V V V A V V A V A V V A A CYA30 T. aestivum V V V V V V V V V A V V A A A V V A A CYA29 T. aestivum V V V V V V V V V A V V A A A V A A A CYA28 T. aestivum V V V V V V V V V A V A A A A V A A A CYA23 T. aestivum V V V V A V V V V A V A A A A A A A A CYA17 T. aestivum VA V A VA A VA V A A A AV A A A A A A A A
  26. 26. Berberis spp. No. of aecia Number of isolate* Rate (%) IT 0 IT 1-2 Pst Pgt Pst Pgt B. shensiana 3677 3630 40 4 3 0.11 0.08 B. brachypoda 4477 4406 59 8 4 0.17 0.15 B. sp. (Tibet) 1163 1150 6 4 3 0.34 0.26 Total 9317 9174 105 16 12 0.17 0.13 *IT 0 indicates no any necrosis, or/and chlorosis on wheat after inoculation, IT1-2 indicates necrosis, or/and chlorosis; Pst=Puccinia striiformis f. sp. tritici; Pgt=Puccinia graminis f. sp. tritici Pst isolates obtained from the infected Berberis spp. in Gansu, Shaanxi and Tibet in 2013
  27. 27. Berberis (origin) Isolate No. Chinese differential hosts for Pst 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 (ck) Race / race group   U1 AV V V V V V V V A V V A V VA A AV A A A V SuG   U2 A V V V V V V V A V AV A A V A A A A A V SuG    B.aggregata (Gansu)   U3 A V A AV V V V V A V AV A A V A A A A A V SuG U4 AV A V V AV V V V A V V V A V A V A A A V SuG U5 V V V V V V V V V V V V V V A V V A A V CYR32 U6 A V AV V V V V V A V V V A V A A A A A V SuG   U7 V V V V V V V V A V V AV A V A A A A A V SuG   U8 V V V V V V V V V V V V V V A V V A A V CYR32 B.shensiana (Shaanxi)       U 9 V V V V V V V V V V V V V V A V V A A V CYR32 U10 V V V V V V V V V V V V V V V V A A A V SuG U11 A V A V V V V V A AV AV A A V A A A A A V SuG U12 A V A AV V V V V A V AV A A V A A A A A V SuG B.sp.   (Tibet) U13 AV V V V A V V V A V V A A V A A A A A V SuG U14 A V V V V V VA V A V V A A V A A A A A V SuG U15 AV V V AV A V V A A V A A V V A A A A A V SuG U16 A V A AV A V V V A A AV A A V A A A A A V SuG •  3 recovered isolates were identified as race CYR 32. •  Other 13 isolates have different virulence patterns as compared to the major Chinese races , and can be considered as new races. Chinese differential hosts for Pst A=avirulent ; V=virulent; AV/VA =segeration of resistant and susceptible; ck=Mingxian 169 susceptible to Pst. SuG=race group virulence for Suwon 11(YrSu); HyG=race group virulence for Hyrbrid 46 (Yr3b,Yr4b) CYR= chinese yellow rust Virulence patterns of 16 recovered isolates on Chinese differential host sets
  28. 28. Single Aecia from barberry Recovered isolate from single aecium Single uredium (Su) isolates Virulence test on NILs Does the sexual reproduction under natural conditions contribute to virulence variation for Pst ? •  120 single-uredium (SU) isolates were make from 16 recovered isolates from infected barberry. •  Virulence test for each SU isolates on near-isogenic lines. •  Remarkable variation in virulence patterns among the SU isolates.
  29. 29. Virulence patterns of single-uredium isolates from recovered Pst isolate on near-isogenic lines SU isolate Yr NILs 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 Yr2 Yr5 Yr6 Yr7 Yr8 Yr9 Yr10 Yr15 Yr17 Yr24 Yr26 Yr27 Yr44 YrSp YrTr1 YrExp2 Yr25 Yr28 CK U10* VA A V A A A A A A A AV A V A A A V V V U10-1 A A V A A V A A A A A A V A A A V V V U10-2 A A V A A A A A A A A A V A A A V V V U10-3 A A V A A A A A A A A A V A A A V V V U10-4 A A V A A V A A A A A A V V A A V V V U10-5 A A V A A V A A V A A A V V A A V V V U10-6 V A V AV A A A A V A A A V V A A V V V U10-7 A A V A A V A A V A A V V V A A V V V U10-8 A A V A A V A A A A A A V A A A V V V U10-9 A A V AV A V A A A A A A V A A A V V V •  SU isolates U10-2 and U10-3 share the same virulence patterns, •  Other 7 SU isolates have different virulence patterns. *U10 isolate recovered from Berberis shensiana in Shaanxi
  30. 30. SU isolate Yr NILs 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 Yr2 Yr5 Yr6 Yr7 Yr8 Yr9 Yr10 Yr15 Yr17 Yr24 Yr26 Yr27 Yr44 YrSp YrTr1 YrExp2 Yr25 Yr28 CK U2* A A A AV V A A A A A V A A A A V A A V U2-1 A A A AV V A A A A A V A A A A V A A V U2-2 A A A A V A A A AV A V A V A A V A A V U2-3 A A VA AV V A A A A A V A A A A A A A V U2-4 A A A A V A A A V A V A V A A V A A V U2-5 A A AV A V A A A A A V A A A A V A V V U2-6 A/V A V V V A A A A A V A V A A V A A V U2-7 A A A A V A A A A A V A A A A V A A V U2-8 VA A V A/VA V A A A V A V A VA A A V A A V U2-9 A A AV A V A A A A A V A V A A V A A V U2-10 A A A A V A A A A A V A A A A V A A V U2-11 A A AV VA V A A A A A V A A A A V A A V U2-12 A A AV A V A A A A A V A A A A V A A V U2-13 A/VA A A/V A V A A A V A V A A A A V A A V U2-14 A/V A A/V A/VA V A A A A A V A A/V A A V V VA V “/” indicates various infection type on first and second leaf of genotype wheat cultivar. AV, VA= segregation of resistant and susceptible. *U2 isolate recovered form Berberis aggregata in Gansu. •  U2-7 and U2-10, share the same virulence patterns, •  Other 12 SU isolates have different virulence patterns. Virulence patterns of single-uredium isolates from recovered Pst isolate on near-isogenic lines
  31. 31. Single Aecia from barberry Recovered isolate from single aecium Single uredium (Su) isolates Virulence test on NILs Does the sexual reproduction under natural conditions contribute to virulence variation for Pst? •  The single-uredium isolates originally from aecia on naturally infected barberry plants consisted of diverse of virulence patterns, which may be due to sexual reproduction on the barberry plants.
  32. 32. Ø  23 of the 30 tested barberry species show susceptibility to Pst, indicating that there is a great diversity of potential alternate hosts for Pst in China. Ø  20 Pst isolates obtained from different barberry species in the fields indicated that the sexual stage of Pst occurs under natural conditions. Ø  Virulence tests for single-uredium isolates recovered from a single aecium demonstrate that the sexual reproduction contributes to virulence variation for Pst. Ø  23 isolates of wheat stem rust were obtained from 4 barberry species in the fields, indicating that the sexual stage of wheat stem rust also occurs under natural conditions in China. Summary
  33. 33. Ø  The earmarked fund for Modern Agro-industry Technology Research System in China Ø  National Basic Research Program of China (973) Ø  Nature Science Foundation of China Ø  The 111 Project from the Chinese Ministry of Education Acknowledgement Dr. Jie Zhao Prof. Lili Huang Dr. Hongchang Zhang Dr. Gangming Zhan Dr. Qingmei Han Dr. Yonghong Zhang Dr. Dejun Han Dr. Xiaojie Wang Dr. Jun Guo Dr. Xueling Huang Dr. Wenming zheng Mrs. Guorong Wei All PhD and Master students 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. Chong Dr. Yue Jin, Dr. Ravi Singh, Dr. Zacharias Pretorius
  34. 34. Thanks for your attention!

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