Puccinia graminis f. sp. tritici Avr-r45; identification of an effector that manipulates an integrated domain R-protein complex
R. SHARMA POUDEL (1), J. Richards (1), S. Solanki (1), R. Brueggeman (1) (1) North Dakota State University, U.S.A.

Stem rust, Puccinia graminis f. sp. tritici (Pgt) race TTKSK is virulent on most wheat and barley cultivars. The rpg4/Rpg5 (r45) resistance locus in barley provides effective resistance against many Pgt races, including TTKSK and its lineage. The functional r45 resistance gene is Rpg5, which encodes a typical NLR R-gene with a putative C-terminal protein kinase sensory domain. Genetic and functional data support the integrated sensory domain model as the mechanism of r45-Avr45 interaction. To validate this hypothesis, the Pgt effector/avirulence proteins Avr45 needs to be characterized. To identify Avr45, 37 Pgt isolates collected in North Dakota with differential virulence on the r45 gene were genotyped utilizing Restriction site Associated DNA-Genotyping by Sequencing to identify 24 diverse isolates. In planta RNAseq was conducted by collecting infected tissue from the susceptible barley variety Harrington, 5 DPI with the 24 Pgt isolates. Seven predicted small-secreted Avr-r45 candidate genes were identified using comparative analysis showing expression in avirulent isolates and lack of expression in virulent isolates. These candidates were transformed into Pichia pastoris for protein expression and infiltration of the purified proteins correlating with HR responses in barley lines that are r45+/- should identify strong Avr45 candidate genes. A full scale Y2H library of infected barley using the Rpg5 PK domain as bait will also be utilized to identify Avr45.

Abstract Number: P9-306
Session Type: Poster