PSEUDOMONAS-CEPACIA CAUSES MYCELIAL DEFORMITIES AND INHIBITION OF CONIDIATION IN PHYTOPATHOGENIC FUNGI

Pseudomonas cepacia, a common soil and rhizosphere inhabitant, showed strong antagonism against several fungal plant pathogens. In dual cult ures it greatly restricted the growth and conidial formation in severa l of these fungi. Growth restriction was associated with the frequent induction of a variety of morphological abnormalities such as chlamydo conidium formation, hyphal swellings, vacuolation and granulation of t he mycelial contents, as well as lysis of hyphae and conidia. The indu ction of these deleterious morphological changes in fungi and inhibiti on of conidial formation were also found with a crude preparation of a n antifungal compound from P. cepacia. Mutants, defective in the produ ction of this antifungal compound, failed to induce these morphologica l changes; this suggests that the antifungal compound is responsible f or these abnormalities.