Your SlideShare is downloading. ×
  • Like
2014 bgri dracatos rev
Upcoming SlideShare
Loading in...5
×

Thanks for flagging this SlideShare!

Oops! An error has occurred.

×

Now you can save presentations on your phone or tablet

Available for both IPhone and Android

Text the download link to your phone

Standard text messaging rates apply
Published

 

Published in Technology
  • Full Name Full Name Comment goes here.
    Are you sure you want to
    Your message goes here
    Be the first to comment
    Be the first to like this
No Downloads

Views

Total Views
68
On SlideShare
0
From Embeds
0
Number of Embeds
0

Actions

Shares
Downloads
2
Comments
0
Likes
0

Embeds 0

No embeds

Report content

Flagged as inappropriate Flag as inappropriate
Flag as inappropriate

Select your reason for flagging this presentation as inappropriate.

Cancel
    No notes for slide

Transcript

  • 1. Australian Cereal Rust Control Program Non-Host Resistance, Near-Host Resistance, or Just Resistance? Dr Peter Dracatos Plant Breeding Institute Cobbitty Australia
  • 2. Concepts of Non-Host Resistance and Near Host Resistance •  Most plants are resistant to most pathogens •  Rusts are highly specialised •  Non-Host resistance: –  i.e. Puccinia graminis f. sp. tritici (Pgt) on rice and dicot plants •  Near-host resistance –  Some genotypes of closely related cereals to the host are susceptible •  Barley to P. graminis f. sp. avenae (Pga) and P. striiformis f. sp. tritici (Pst) •  Wheat to P. graminis f. sp. secali (Pgs)
  • 3. • Watson and Sanghi (1968) showed that resistance in wheat to Pgs was simply inherited (e.g. Yalta = 1 gene, Morocco = 2 genes, Mentana = 4 genes) • Martens in 1983 showed that 1 gene shared between 3 barley lines provided resistance to Pga and this was different to that for Pgt • Niks and Boyd Near-host resistance in barley to different rusts and powdery mildew • Ayliffe (CSIRO) – why is rice immune to rust (Non-Host Resistance)? –  Simple inheritance of resistance to Pga and Pst in Brachypodium Background
  • 4. Applications in Plant Breeding •  Potentially a large reservoir of resistance •  Important rust resistance genes sourced from closely related species –  Wheat Stem Rust: Secale cereale, Thinopyrum ponticum, Triticum spp –  Barley Leaf Rust: Hordeum bulbosum •  Could we clone these genes and swap them between cereal species that are not inter-crossable? –  Cassettes of multiple genes from different species •  Implications for durability and gene stewardship •  Understand more about P. graminis – cereal pathosystem –  What cereal species play a role in epidemiology
  • 5. Outline of Presentation • Mendelian inheritance – Near–Host resistance • Pathotype-specific vs non-specific resistance • Near-host resistance –  Large variation and overlap in varieties • Specific examples –  Resistance in barley to: •  P. graminis formae speciales •  Pst –  Resistance in oats: •  Pgt
  • 6. 10a   Pgt ‘Yerong’ Barley ‘Franklin’ Barley ‘Swan’ Oat ‘Morocco’ Wheat Host specificity of Pgt vs Pga Pga
  • 7. Resistance in Barley to formae speciales of Pg
  • 8. Resistance to Pga in Barley •  35 DH populations assessed for resistance to Pga –  Mostly R x R crosses •  Susceptible varieties of barley –  High infection types (IT) noted in 12 populations –  Suitable for intercrossing •  Segregation in many cases to more than one resistance gene •  Numerous phenotypic variation for resistance –  ITs similar to host-pathogen interactions –  Complete immunity –  Incomplete susceptibility •  Mesothetic ITs
  • 9. Resistance in Yerong x Franklin to Pga
  • 10. Genetic  Analysis  in  Yerong  x  Franklin  
  • 11. Rpg5 Resistance in Barley to Pgt, Pga and Pgs •  Q21861 carries Rpg1 and rpg4/Rpg5 •  Bruggeman et al. –  rpg4/Rpg5 - resistance to Pgt including Ug99 –  Rpg5 – resistance to Pgs •  F8 RIL population Q21861 x F line –  F line - mesothetic susceptibility to Pga and Pgt –  Screened with Pga and Pgt –  Fixed for Rpg1 –  1:1 segregation for Pgt and Pga –  Marker analysis demonstrates effectiveness of Rpg5 against multiple f. spp. of P. graminis •  Such genes may be particularly important for transfer into target cereal species
  • 12. Resistance in Oats to Pgt
  • 13. “Near-host” resistance eat stem rust on oats TTKST Ug99 +Sr24 TRTTF-virulence to Sr13 and Sr9e Wheat Hexaploid oats Diversity of Resistance to Pgt in oats
  • 14. Diverse International Oat Screening •  600 internationally diverse oat lines inoculated with: •  P. graminis f. sp. tritici •  Range of infection types •  ;;nnn, ;n, ;;, ;cn, 22+ •  95 lines - showed ITs >0; Pgt •  Selected lines above plus lines from diverse origin giving immune ITs (0;) will be used for Association mapping analysis 14  
  • 15. Resistance to Puccinia striiformis f. sp. tritici (Pst) in Barley
  • 16. Plant Genotype P. striiformis f. sp. tritici Ps f. sp. pseudohordei 1979 pt 2002 pt Barley Finniss ;c 0; 23c Maritime 2c/2cn ;c 3 Fong Tien 22+ 3 3 Commander 0; ; 0; Hindmarsh 0; 0; 0; Wheat Morocco 3+ 3+ ;/1p 3+ Chinese 166 ; 0; 33+ Different ITs in Barley to Pst •  Susceptibility in barley •  Pst •  P. striiformis f. sp. pseudohordei •  Variation of resistance in barley between: •  P. striiformis pathotypes •  P. striiformis f. sp.
  • 17. 5X 5X Commander M2.7 resistant sib 7dpi Commander M2.7 susceptible 7dpi Chlorosis but no pustules 5X Putative Resistance Gene Knockouts 5X •  Finnis and Commander M3 progeny tested candidates •  6 Finnis families •  2 Commander families
  • 18. Fong TienHindmars h Hindmarsh*Fong BC1 F2 # 3 #3 Hindmarsh*Fong BC1 F2 # 3 14dpi 3: 1 ratio indicating single gene from Hindmarsh Mapping and mutagenesis in progress Resistance to Pst in Barley
  • 19. Summary – Near-Host resistance •  Barley suitable for genetic analysis of resistance to different Puccinia species •  Resistance is Resistance! –  Necrosis, chlorosis, flecking, reduced sporulation •  Large variability of ITs and mechanisms of resistance •  R genes confer resistance to different formae speciales •  Pre-haustorial •  Pathotype specific- formae speciales specific •  Future work •  Fine-map and cloning of resistance genes and transfer to target cereals
  • 20. Acknowledgements University of Sydney •  Dr Davinder Singh •  Professor Robert Park CSIRO Canberra •  Shidah Mojerlou •  Dr Wolfgang Spielmeyer •  Dr Michael Ayliffe Canada Agriculture •  Dr Tom Fetch The Sainsbury Laboratory •  Dr Brande Wulffe •  Dr Matthew Moscou