Catenarin Production by Isolates of Pyrenophora tritici‐repentis (Died.) Drechsler and its Antimicrobial Activity

A total of 88 Pyrenophora tritici‐repentis (Died.) Drechsler isolates from different hosts and localities were screened for catenarin production using thin layer chromatography. Catenarin was detected in 29% of the tested strains. The level of this compound ranged from 2 to 400 ppm and was especially high in case of fungus variants unable to biosynthesize melanins. The extracted pigment exhibited antibiotic properties against Gram‐positive bacteria (Aureobacterium liquefaciens, Arthrobacter globiformis, Bacillus brevis, B. circulans, B. subtilis and Curtobacterium plantarum). Catenarin also inhibited the growth of fungi accompanying P. tritici‐repentis during the saprophytic phase of development. The most sensitive species was Epicoccum nigrum, whose growth was inhibited up to 90%.