Tulip Gums Elicit Bikaverin Production in the Isolates of <em>Fusarium oxysporum</em> Pathogenic for Tulip Bulbs

The Fusarium oxysporum fungus under some stress conditions produce intracellular secondary metabolites including naphthoquinone pigments. One of such stressors/elicitors are tulip gums. It is interesting to mention that tulip gums induced red pigment synthesis by Fusarium oxysporum pathogenic for tulip bulbs but did not elicit the red pigment for-mation through mycelium of F. oxysporum f. sp. callistephi, F. oxysporum f. sp. dianthi and F. oxysporum f. sp. narcissi. In present research the red color pigment was analyzed and its composition was confirmed by UV and mass spectrometry to include bikaverin and norbikaverin as predominant components. Their intracellular concentration was quite high and was increasing during the incubation period from 3.58 after 7 days of incubation up to 5.64 mg per 100 mg of myce-lium dry mater after 15 days. Due to the interest in naphthoquinone pigment application in pharmaceutical drug de-velopment, industrial application and agriculture, this finding may be an alternative for development of new processes of bikaverin synthesis. On the other hand, since this mechanism was observed only for Fusarium oxysporum pathogenic to tulips physiological role of these compounds in tulips would be of great interest.