EVALUATION OF A POLYCLONAL ANTIBODY IMMUNOASSAY FOR DETECTION AND QUANTIFICATION OF MACROPHOMINA-PHASEOLINA

Detection and quantification of Macrophomina phaseolina, causal agent of charcoal/dry root rot disease in many crop plants, was carried out using the ELISA serological technique. Polyclonal antisera raised to w ater soluble extracts of mycelium, the residual water insoluble myceli al materials or ribosomal proteins were evaluated for specificity and cross-reactivity with 16 common soil fungi by ODD and DAS-ELISA. Solub le and cell wall antisera exhibited strong cross-reactivity with most of the fungal isolates. Ribosomal antibodies were less reactive to com mon soil fungi except Fusarium oxysporum f.sp. ciceri. Mycelial antige ns of M. phaseolina on chickpea roots were detectable with DAS-ELISA a t a minimum concentration of 10 ng g(-1) at 1:100 root:buffer dilution . Quantitative estimation of M. phaseolina on roots was evaluated by E LISA under different temperatures and moisture conditions, and in soil amended with a potential antagonist (Trichoderma harzianum 25-92). A significant reduction in ELISA values was observed in T. harzianum-ame nded treatments. This method may be useful for detection and rapid scr eening of M. phaseolina under different environmental conditions.