Environmental influences in the development ofPhycomyces sporangiophores

́rrez-Corona, Fe ́lix Gutie; Olmedo, Enrique Cerdá

doi:10.1016/0147-5975(85)90047-7

Cited by 11 publications

(1 citation statement)

References 19 publications

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“…Light guides the giant sporangiophores of this fungus (macrophores) as they grow several centimeters into the air lifting a sporangium filled with ca lo5 spores. Phycomyces exhibits many other photoresponses: Light stimulates the production of the yellow pigment, P-carotene (photocarotenogenesis) (5), and the development of sporangia (6) and macrophores (photomacrophorogenesis) (7-1 1) and inhibits sexual development (12) and the production of microphores (photomicrophorogenesis) (8,10,11 Brief illumination under certain conditions (1 1) shows that light influences the development of both kinds of sporangiophores in cultures aged 32-68 h, with a maximum at the age of 48 h (13). Only blue and near-ultraviolet radiations are effective.…”

Section: Introductionmentioning

confidence: 99%

Separate Sensory Pathways for Photomorphogenesis in Phycomyces

Flores

Cerdá‐Olmedo

Corrochano

1998

Photochem & Photobiology

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The zygomycete Phycomyces blakesleeanus develops two types of sporangiophores of very different size: macrophores and microphores. Blue light inhibits the development of microphores and stimulates the development of macrophores. These responses are called photomicrophorogenesis and photomacrophorogenesis, respectively; phototropism designates the growth of the macrophores toward blue light and photocarotenogenesis, the increased accumulation of β‐carotene under blue light. We have isolated three pim mutants that develop microphores under continuous illumination at fluence rates that inhibit them in the wild type. The thresholds for photomicrophorogenesis in the mutants were higher than in the wild type, but the thresholds for photomacrophorogenesis and phototropism did not change. At least one of the pim mutants had a much higher threshold for photocarotenogenesis than the wild type. A madJ mutant strain, already known for its very defective phototropism, was defective for photomicrophorogenesis, but normal for photomacrophorogenesis and photocarotenogenesis. The requirement for the pim and madJ gene functions separates the two photomorphogenetic responses. The results indicate that the four responses to blue light are based on a combinatorial use of sensory transducers.

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Section: Introductionmentioning

confidence: 99%

Separate Sensory Pathways for Photomorphogenesis in Phycomyces

Flores

Cerdá‐Olmedo

Corrochano

1998

Photochem & Photobiology

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Genetic determination of sporangiophore development in Phycomyces

Gutiérrez-Corona

Cerdé-Olmedo

1988

Dev. Genet.

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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 2 6 T , 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 ma& and ma&, 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.

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Spore activation by acetate, propionate and heat in Phycomyces mutants

Rivero

Cerdá‐Olmedo

1987

Mol Gen Genet

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Exposure to heat, acetate, or propionate activates the spores of the fungus Phycomyces blakesleeanus and allows them to germinate. Using counterselection with the antibiotic N-glycosyl-polyfungin, seven mutants were isolated on the basis of decreased spore activation by propionate. The nine mutants showed decreased activation by both chemicals and by heat, increased heat lethality, and altered patterns of trehalase activation. These and other observations indicate that spore activation by the three agents and spore death by heat are mediated by the same cellular component(s), which is probably involved in the regulation of cyclic AMP concentration.

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Environmental influences in the development ofPhycomyces sporangiophores

Cited by 11 publications

References 19 publications

Separate Sensory Pathways for Photomorphogenesis in Phycomyces

Separate Sensory Pathways for Photomorphogenesis in Phycomyces

Genetic determination of sporangiophore development in Phycomyces

Spore activation by acetate, propionate and heat in Phycomyces mutants

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