Karnal bunt (KB) of wheat incited by Tilletia indica is an economically important quarantined fungal pathogen. Similarity in teliospore configuration makes it difficult to differentiate KB teliospores from the teliospores of other bunt fungi using conventional approaches. In order to determine the correct identity of KB teliospore an infectious entity, it is essential to develop specific diagnostic probes and high quality of immunological reagents against infectious entities. The immuno-dipstick assay developed in our lab is quite sensitive to detect the antigens of even five teliospores. For on-site testing of KB, a nano-gold based lateral flow immuno-dipstick assay (LFID) was also developed in our lab using anti-teliospore antibodies. For development of LFID, colloidal gold was prepared and conjugated with anti-teliospore antibodies which were further characterized. However, species specific detection is yet to be achieved by generation of monoclonal antibodies against diagnostic antigens (34 and 66 kD teliospore's proteins). Based on the experience of nano-gold based LFID, we are proposing to develop surface plasmon resonance (SPR) based label-free detection system. The same may be employed not only for determination of the quality of immunological reagents in terms of sensitivity, specificity and precision but also development of suitable design of immunosensor for differential diagnosis of KB (T. indica). The approach involves the use of a mouse monoclonal antibody against diagnostic antigens and a suitable design of SPR sensor by the preparation of immuno-affinity layer over self assembled monolayer surfaces. The signal to noise ratio can further be enhanced using nano-gold particles. This will be first attempt for real-time monitoring of KB teliospores in wheat lots by SPR sensor and in a fully automated manner for establishing seed certification and plant quarantine standards. (C) 2010 Published by Elsevier B.V.