Rust Pathogen Genomics and the Potential Impact on Crop Management Les J. Szabo USDA ARS Cereal Disease Laboratory University of Minnesota St. Paul, MN

Life cycle

Rust pathogens of Avena Puccinia coronata Crown rust Species complex P. coronata f.sp. avenae (oat)

Rust pathogens of Avena Puccinia graminis Stem rust Species complex P. graminis f.sp. avenae (oat) P. graminis f.sp. tritici (wheat & barley)

Rust Fungi Obligate parasites

Rust Fungi Obligate parasites

Fungal - Host interactions Nutrients Effectors

Fungal - Host interactions Nutrients Sugars Hexose transporter (Hxt1) Uromyces fabae/Vicia fabae Glucose and Fructose Haustoria membrane Voegele et al., 2001 PNAS

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

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

Fungal - Host interactions Effectors Manipulate host for the benefit of the fungus Suppress host defense Alter host metabolism

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

Fungal - Host interactions Effectors Trigger host defense response (Avirulence) Melampsora lini /Flax (Linum usitatissimum) AvrL567, AvrM, AvrP4, Avr123 Small ( 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

Fungal - Host interactions Nutrients Effectors

Rust fungal genomes Completed Puccinia graminis f.sp. tritici Wheat stem rust

Rust fungal genomes Completed Puccinia graminis f.sp. tritici Wheat stem rust In process Melampsora larici-populina Popular leaf rust

Rust fungal genomes Completed Puccinia graminis f.sp. tritici Wheat stem rust In process Melampsora larici-populina Popular leaf rust In the Pipe (Fall 2008) Puccinia triticina Wheat leaf rust

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

P. graminis genome Current focus Sequence additional isolates

P. graminis genome Current focus Sequence additional isolates In planta expressed genes Microarray ESTs Isolates representing different races

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

Future Define P. graminis avirulence genes for know resistance genes Develop molecular assays for defining races?

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.

Novel control mechanisms Nutrients Effectors X Targets for novel R genes

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