After germination of urediospores of three Puccinia striiformis f. sp. tritici (Pst) strains including the original strain CYR32 (a dominant physiological race of Pst in China) and two virulence-mutant strains (CYR32-5 and CYR32-61) acquired from CYR32 by UV-B radiation, proteomic analysis of the strains was investigated using the proteomics method based on isobaric tags for relative and absolute quantification (iTRAQ) technology.