Slide 1

Rust Pathogen Genomics and the Potential Impact on Crop Management Les J. Szabo USDA ARS Cereal Disease Laboratory University of Minnesota St. Paul, MN Slide 2 Life cycle Slide 3 Rust pathogens of Avena Puccinia coronata Crown rust Species complex P. coronata f.sp. avenae (oat) Slide 4 Rust pathogens of Avena Puccinia graminis Stem rust Species complex P. graminis f.sp. avenae (oat) P. graminis f.sp. tritici (wheat & barley) Slide 5 Rust Fungi Obligate parasites Slide 6 Rust Fungi Obligate parasites Slide 7 Fungal - Host interactions Nutrients Effectors Slide 8 Fungal - Host interactions Nutrients Sugars Hexose transporter (Hxt1) Uromyces fabae/Vicia fabae Glucose and Fructose Haustoria membrane Voegele et al., 2001 PNAS Slide 9 Fungal - Host interactions Nutrients Sugars Hexose transporter (Hxt1) Uromyces fabae/Vicia fabae Glucose and Fructose Haustoria membrane Invertase (plant and fungal) Sucrose glucose & fructose Voegele et al., 2001 PNASVoegele et al., 2006, MPMI Slide 10 Fungal - Host interactions Nutrients Sugars Hexose transporter (Hxt1) Uromyces fabae/Vicia fabae Glucose and Fructose Haustorial membrane Invertase (plant and fungal) Sucrose glucose & fructose Mannitol dehydrogenase (Mad1) Fructose mannitol Haustorial cytoplasm Voegele et al., 2001 PNASVoegele et al., 2006, MPMIVoegele et al., 2005 Plant Phys Slide 11 Fungal - Host interactions Effectors Manipulate host for the benefit of the fungus Suppress host defense Alter host metabolism Slide 12 Fungal - Host interactions Effectors Manipulate host for the benefit of the fungus Suppress host defense Alter host metabolism Rpt1 (U. fabae) Transported in the plant cytoplasm Kemen et al., 2005 MPMI Slide 13 Fungal - Host interactions Effectors Trigger host defense response (Avirulence) Melampsora lini /Flax (Linum usitatissimum) AvrL567, AvrM, AvrP4, Avr123 Small (95-377 aa) Expressed in haustoria 1-4 copies per genome Secreted into plant host cytoplasm Cysteine-rich (AvrP4, AvrP123) Dodds et al., 2006 Plant Cell; Catanzariti et al., 2006 Plant Cell Slide 14 Fungal - Host interactions Nutrients Effectors Slide 15 Rust fungal genomes Completed Puccinia graminis f.sp. tritici Wheat stem rust www.broad.mit.edu Slide 16 Rust fungal genomes Completed Puccinia graminis f.sp. tritici Wheat stem rust www.broad.mit.edu In process Melampsora larici-populina Popular leaf rust www.jgi.doe.gov Slide 17 Rust fungal genomes Completed Puccinia graminis f.sp. tritici Wheat stem rust www.broad.mit.edu In process Melampsora larici-populina Popular leaf rust www.jgi.doe.gov In the Pipe (Fall 2008) Puccinia triticina Wheat leaf rust Slide 18 P. graminis genome Assembly 392 supercontigs 89 Mb 7X coverage Annotation 20,567 predicted genes 1,386 predicted to be secreted 393 cysteine-rich 80,000 ESTs Microarray Slide 19 P. graminis genome Current focus Sequence additional isolates Slide 20 P. graminis genome Current focus Sequence additional isolates In planta expressed genes Microarray ESTs Isolates representing different races Slide 21 P. graminis genome Current focus Sequence additional isolates In planta expressed genes Microarray ESTs Isolates representing different races Screen candidate effector genes in planta Induce HR response Slide 22 Future Define P. graminis avirulence genes for know resistance genes Develop molecular assays for defining races? Slide 23 Future Define P. graminis avirulence genes for know resistance genes Develop molecular assays for defining races? Define effector genes that are involved in host-range. Compare effector genes between P. graminis f.sp. tritici and P. graminis. f.sp. avenae. Slide 24 Novel control mechanisms Nutrients Effectors X Targets for novel R genes Slide 25 Players USDA ARS Cereal Disease Lab USDA ARS Cereal Disease Lab Shaobin Zhong, Charlie Barnes and Jerry Johnson Shaobin Zhong, Charlie Barnes and Jerry Johnson Broad Institute, MIT and Harvard Broad Institute, MIT and Harvard Christina Cuomo and company Christina Cuomo and company CIFR, North Carolina State U CIFR, North Carolina State U Ralph Dean, Doug Brown Ralph Dean, Doug Brown BC Cancer Research Center BC Cancer Research Center Jacqueline Schein Jacqueline Schein Funding: NSF Funding: NSF