Modification of Blue Light Photoresponses by Riboflavin Analogs in Neurospora crassa

The effect of riboflavin analogs on blue light responses in a riboflavin mutant of Neurospora crassa was studied. The analogs 1-deazariboflavin and roseoflavin, which have red-shifted absorption, acted as photoreceptors for the photosuppression and phase shifting of circadian conidiation by 540 nm light, but were ineffective as photoreceptors for the induction of carotenoid synthesis. These results provide addtional evidence implicating a flavin photoreceptor for at least two blue light responses of Neurospora.