Effect of Glucose, Ammonium and Media Maintenance on the Time of Conidiophore Initiation by Surface Colonies of Aspergillus nidulans

Pastushok, M.; Axelrod, David E.

doi:10.1099/00221287-94-1-221

Cited by 34 publications

(25 citation statements)

References 3 publications

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“…In contrast to many other cases of microbial development, A. nidulans conidiophore development initiates primarily as a programmed part of the life cycle rather than as a response to an unfavorable environment (21). Strains lacking the acoD gene no longer make conidiophores as a normal part of their life cycle but now respond to growth-limiting conditions by initiating development.…”

Section: Resultsmentioning

confidence: 99%

“…These cells initiate development when exposed to an airwater interface and give rise to conidiophores that then produce thousands of mitotically derived spores. The mechanisms controlling the acquisition of developmental competence followed by a switch from undifferentiated growth to conidiophore development are largely unknown but apparently are genetically determined (5,11), with competence arising as a programmed event in the life cycle rather than as a response to unfavorable environmental conditions (21).…”

mentioning

confidence: 99%

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Isolation of a gene required for programmed initiation of development by Aspergillus nidulans.

et al. 1992

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In contrast to many other cases in microbial development, Aspergillus nidulans conidiophore production initiates primarily as a programmed part of the life cycle rather than as a response to nutrient deprivation.Mutations in the acoD locus result in "fluffy" colonies that appear to grow faster than the wild type and proliferate as undifferentiated masses of vegetative cells. We show that unlike wild-type strains, acoD deletion mutants are unable to make conidiophores under optimal growth conditions but can be induced to conidiate when growth is nutritionally limited. The requirement for acoD in conidiophore development occurs prior to activation of brL4, a primary regulator of development. The acoD transcript is present both in vegetative hyphae prior to developmental induction and in developing cultures. However, the effects of acoD mutations are detectable only after developmental induction. We propose that acoD activity is primarily controlled at the posttranscriptional level and that it is required to direct developmentally specific changes that bring about growth inhibition and activation of brUA expression to result in conidiophore development.

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Section: Resultsmentioning

confidence: 99%

mentioning

confidence: 99%

Isolation of a gene required for programmed initiation of development by Aspergillus nidulans.

et al. 1992

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“…However, nutritional stress must play a secondary role in induction of sporulation, because nutrient limitation reduces conidiation of surface-grown colonies and continuous replacement of growth medium beneath a surface-grown colony does not repress conidiation (226). A fraction of hyphal cells may be nutrient limited and thereby induced to develop.…”

Section: Physiological Requirements For Asexual Sporulationmentioning

confidence: 99%

“…The initiation of conidiation is contingent upon cells having undergone a defined period of growth (20 h) to reach developmental competence (15). Developmental competence is an intrinsically programmed process that is independent of external changes in growth medium; continuous transfer to fresh growth medium and growth of cells at low densities have no effect on the timing of conidiation (226). In fact, while sporulation in many microorganisms occurs in response to adverse environmental conditions, the signals that induce A. nidulans differentiation are not well defined.…”

Section: Physiological Requirements For Asexual Sporulationmentioning

confidence: 99%

Signal Transduction Cascades Regulating Fungal Development and Virulence

Lengeler

Davidson

D’Souza

et al. 2000

Microbiol Mol Biol Rev

833

774

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SUMMARY Cellular differentiation, mating, and filamentous growth are regulated in many fungi by environmental and nutritional signals. For example, in response to nitrogen limitation, diploid cells of the yeast Saccharomyces cerevisiae undergo a dimorphic transition to filamentous growth referred to as pseudohyphal differentiation. Yeast filamentous growth is regulated, in part, by two conserved signal transduction cascades: a mitogen-activated protein kinase cascade and a G-protein regulated cyclic AMP signaling pathway. Related signaling cascades play an analogous role in regulating mating and virulence in the plant fungal pathogen Ustilago maydis and the human fungal pathogens Cryptococcus neoformans and Candida albicans. We review here studies on the signaling cascades that regulate development of these and other fungi. This analysis illustrates both how the model yeast S. cerevisiae can serve as a paradigm for signaling in other organisms and also how studies in other fungi provide insights into conserved signaling pathways that operate in many divergent organisms.

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“…The latter two cell types are uninucleate cells with the phialide undergoing repeated mitotic divisions to yield chains of conidia (Mims et al 1988;Sewall et al 1990). The genetic hierarchy controlling conidiation can be divided into preinduction and postinduction loci (Clutterbuck 1969(Clutterbuck , 1977Axelrod et al 1973;Pastushok and Axelrod 1976;Champe et al 1981;Yager et al 1982;Butnik et al 1984). After conidium germination, preinduction loci determine biochemical events that allow the vegetative mycelia to acquire reproductive competence.…”

mentioning

confidence: 99%

StuA is required for cell pattern formation in Aspergillus.

Miller¹,

Wu²,

Miller³

1992

Genes Dev.

189

209

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The stunted (stuA) gene product is required for the orderly differentiation and spatial organization of cell types of the Aspergillus nidulans conidiophore. Expression of the stuA gene is complex. Two transcripts, stuA~ and stuA~, are initiated from separate promoters. Transcription of both RNAs increases -50-fold during the establishment of developmental competence. Induction-dependent transcriptional and post-transcriptional regulatory mechanisms further enhance expression 15-fold. Consistent with the latter observation, both transcripts have structural features characteristic of RNAs subject to translational control. Conidiophore morphogenesis requires regulatory interactions between the products of the stuA, bristle (brlA), and abacus (abaA) genes. Enhanced stunted expression is cell type specific and dependent on a functional BrlA protein.StuA affects the spatial localization of AbaA by acting directly, or indirectly, to repress abaA expression.

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Effect of Glucose, Ammonium and Media Maintenance on the Time of Conidiophore Initiation by Surface Colonies of Aspergillus nidulans

Cited by 34 publications

References 3 publications

Isolation of a gene required for programmed initiation of development by Aspergillus nidulans.

Isolation of a gene required for programmed initiation of development by Aspergillus nidulans.

Signal Transduction Cascades Regulating Fungal Development and Virulence

StuA is required for cell pattern formation in Aspergillus.

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