An elicitor molecule has been separated from Macrophomina phaseolina, the root rot pathogen of mungbean (Vigna radiata). Cell cultures of mungbean cultivars one resistant and another susceptible to the pathogen, which responded to the elicitor have been established. The elicitor treatment induced rapid increases in phenolic synthesis, activation of phenylalanine ammonia-lyase and peroxidase in the cultured cells. Relative increases in phenolic synthesis and peroxidase activity were observed in suspension-cultured cells of the resistant cultivar compared to that of the susceptible one due to elicitor treatment