Reactive oxygen species (ROS) have been regarded as inevitable harmful by-products of aerobic metabolism. Growing evidence, however, suggests that ROS play important physiological roles. The phagocyte NADPH oxidase was the first example of an enzyme dedicated to ROS production. The catalytic component of this oxidase (NOX2) utilizes NADPH and O2 to generate O2"¢-. Novel members of the NOX family have been described in plants and animal non-phagocytic cells. In fungi, a phylogenetic analysis shows the presence of three new subfamilies (NOXA, B and C). The number of nox genes in fungi ranges from none in yeasts and dimorphic U. maydis and C. neoformans to one, two and three, revealing an interesting correlation between the presence of nox genes and the capability to develop multicellular fruiting bodies. In A. nidulans, ROS are generated during differentiation of cleistothecia. Inactivation of the NOX NoxA markedly reduces ROS production and blocks cleistothecia development at an early stage , while noxA derepression correlates with premature and abundant development of cleistothecia. Likewise, in N. crassa the inactivation of nox-1 impairs fruiting body development, whereas the inactivation of nox-2 prevents ascospore germination. Our results show that manipulation of reactive species, as strategy to regulate cell differentiation, is ubiquitous in eukaryotes.
Full conference title:
23rd Fungal Genetics Conference
- Fungal Genetics Conference 23rd (2002)