Nucleoside diphosphate kinase-1 regulates hyphal development via the transcriptional regulation of catalase in Neurospora crassa.

A nucleoside diphosphate kinase-1-disrupted (ndk-1(RIP-1)) mutant was observed to be defective in aerial hyphal and conidial development. In this study, two types of hyphae, fine and thick, were observed in wild-type (Wt) strains. However, only fine-type hyphae were observed in the ndk-1(RIP-1) mutants. The ndk-1(RIP-1) mutants were stimulated by oxidative stress and constitutively expressed an antioxidant enzyme catalase (CAT)-3. Furthermore the ndk-1(RIP-1) mutants could form thick hyphae by oxidative stress and a disruption of cat-3. These results suggest that the loss of thick hyphae in the ndk-1(RIP-1) mutants may be caused by the over-expression of cat-3.