Effect of Inhibitors of Enzymatic DNA Methylation on the Formation of Reproductive Structures and Carotenoid Production in Neurospora crassa

The effect of inhibitors of DNA methylation on light-sensitive developmental stages of the filamentous fungus Neurospora crassawas studied. Under conditions of nitrogen starvation, when blue light induced protoperithecia development and inhibited conidia formation, 5-azacytidine (3-300 μM) inhibited protoperithecia formation and stimulated conidia formation (a 700-fold increase after light induction). After treatment of the mycelium with 5-azacytidine, the protoperithecia formation was accompanied by inversely proportional changes in the formation of conidia, both in the dark and after illumination. In the mycelium cultivated on the Vogel's medium, 5-azacytidine (up to 30 μM) and methotrexate (up to 3 μM) stimulated the light-induced carotenoid synthesis by 30%, whereas higher concentrations of these agents were toxic to carotenoid synthesis and growth.[PUBLICATION ABSTRACT]