Immunological characterization of Karnal bunt resistance by differential response of pathogen restriction in a dual culture system

Abstract

For monitoring disease progression and evaluating Karnal bunt resistance dual cultures were established on callus induced from mature embryos of eight host varieties and two non-host varieties inoculated with a sporidial suspension of a virulent strain of Tilletia indica pathogen. Histochemical studies of dual-cultured calluses showed fungal mycelial growth and formation of chlamydospore-like structures that were more profuse in susceptible lines than in resistant and non-host lines. The formation of a zone of hollowness, i.e. a gap between mycelia and host tissue, an indication of pathogen restriction, was seen in resistant hosts and non-hosts but not in susceptible hosts. Detection and quantification of mycelia and teliospores in dual-cultured calluses by immunoassays revealed remarkable difference in the deposition of mycelia and teliospores-like structures. Susceptible calluses supported more abundant mycelial growth than the resistant and non-host co-cultured calluses based on the binding reaction of polyclonal antibodies. © 2005 Taylor & Francis Group Ltd.