By screening for mutants with an altered conidiation rhvthm or altered responses to environmental stimuli we hope to identify mutations which alter clock input, output, or the central oscillator itself, and thus further our molecular dissection of the circadian clock in Neurospora. Photomorphogenesis mutants of Phycomyces . Rafael Flore Luis M. Corrochano, and Enrique Cerda-Olmedo Departmento de Genetica, Universidad de Sevilla, Sevilla, Spain. The sporangiophores of the zygomycete Phycomyces blakesleeanus grow out into the air lifting a sporangium filled with spores. The microphores are dwarf sporangiophores, about 1 mm long.
Illumination increases the production of macrophores and decreases the production of microphores.
The mad mutants were isolated because of the defective phototropism of their macrophores. There are ten unlinked mad genes. Mutations in genes madA and madB are defective not only in phototropism, but in the mycelial responses, photocarotenogenesis and photomorphogenesis. The car mutants suffer various structural and regulatory alterations in the biosynthesis of -carotene. The mutants have revealed that -carotene is not required for photocarotenogenesis or phototropism, but is essential for photomorphogenesis.