ISSN:
0192-253X
Keywords:
Phycomyces blakesleeanus
;
developmental mutants
;
phorogenesis
;
sexual reproduction
;
light
;
carotene
;
Life and Medical Sciences
;
Genetics
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Biology
Notes:
The mycelium of the fungus Phycomyces. essentially a giant multinucleate cell, produces two kinds of asexual reproductive structures, called macrophores and microphores, and a succession of structures for sexual reproduction. Following the treatment of spores with N-methyl-N′ -nitro-N-nitrosoguanidine, conditional imb mutants have been isolated that form no macrophores at 26°C, but do at 14°C. At the restrictive temperature, few imb mutants (2 of 13) develop microphores, and none is able to complete the sexual cycle. This suggests that genes responsible for macrophorogenesis are involved in microphorogenesis and in sexual development as well. Light reduces macrophorogenesis and totally abolishes microphorogenesis in the wild type under the conditions of our experiments. These photomorphogenetic effects require the normal function of genes madA and madB, which are responsible for phototropism. Light inhibits microphorogenesis in the two imb mutants that form microphores at the restrictive temperature. Genetic alterations of carotenogenesis lead to an excess of microphores and a scarcity of macrophores in the dark, but they have little influence on vegetative reproduction in the light.
Additional Material:
2 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/dvg.1020090605
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