Molecular characterization of predominant Indian wheat rust pathotypes using URP and RAPD markers

Abstract

In India, all the three wheat rusts like yellow rust, brown rust, black rust are important. New pathotypes keep on evolving by overcoming the resistance genes present in the new wheat varieties; however, there is dominance of a few pathotypes in each kind of rust. Predominant pathotypes are 40-A and 40-1 (stem rust), 77-5, 104-2, 12-2 (leaf rust) and 78S84 and 46S119 (stripe rust). Molecular characterization of these pathotypes using random amplified polymorphic DNA (RAPD) and universal rice primer (URP) markers showed high polymorphism (75-100%) with amplified bands in range of 250 to 9000 bp. Few primers provided DNA fingerprint distinct to specific rust pathotypes. URP-30F produced DNA band (2.0 kb) unique to yellow rust pathotypes. URP 2F produced a band of 3.5 kb unique to yellow rust, while two bands of 0.8 kb and 1.1 kb specific to leaf rust pathotypes. Moreover, bands of 2.3 kb and 2.4 kb were unique to 40-A and 40-1 stem rust pathotypes respectively. RAPD primer OPA-11 amplified multiple distinct bands specific to leaf rust (1.5 kb and 1.8 kb), stem rust (0.65 and 0.75 kb) and yellow rust (0.8 and 0.55 kb). The analyses of entire fingerprint profile showed formation of three groups corresponding to leaf, stem and stripe rust pathotypes. There was less correlation between URP/RAPD profile and virulence/avirulence behavior of different rust pathotypes.