Pseudomonas cepacia suppression of sunflower wilt fungus and role of antifungal compounds in controlling the disease.

In a field experiment, Pseudomonas cepacia J82rif and J51rif increased sunflower emergence in the presence of the fungus Sclerotinia sclerotiorum. Pyrrolnitrin, aminopyrrolnitrin, and monochloroaminopyrrolnitrin were isolated from J82 and identified by using thin-layer chromatography, high-performance liquid chromatography, and electron impact-mass, UV, and infrared spectroscopy. In growth chamber experiments, two antibiosis-negative mutants were not different from the parent strain in protecting the seeds from the fungus.