Genetic Analysis of the TOR Pathway in
            <i>Aspergillus nidulans</i>

Fitzgibbon, Gregory J.; Morozov, Igor Y.; Jones, Meriel G.; Caddick, Mark X.

doi:10.1128/ec.4.9.1595-1598.2005

Cited by 52 publications

(50 citation statements)

References 28 publications

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“…In S. cerevisiae and A. nidulans, mutations in downstream components of the TOR pathway confer increased resistance to rapamycin (Beck and Hall, 1999;Jacinto et al, 2001;Fitzgibbon et al, 2005). We found that the DmeaB and DareA mutants, but not the complemented strains, were slightly more resistant to rapamycin than the wild type ( Figure 3B).…”

Section: Nitrogen Repression Of Invasive Growth Requires Gln Synthetamentioning

confidence: 58%

“…While TOR is a key player in nitrogen catabolite repression of S. cerevisiae (Beck and Hall, 1999;, its role in filamentous fungi remains controversial. TOR was suggested to have only a minor function in nitrogen metabolism of A. nidulans since mutations in TOR pathway genes did not have significant effects on the nitrogen utilization phenotype (Fitzgibbon et al, 2005). The discrepancy could partly be explained by the fact that several components of the TOR and nitrogen regulatory pathways, such as Ure2, MeaB, or Nmr1, are not conserved between S. cerevisiae and filamentous fungi.…”

Section: Role Of Tor and Meab In Nitrogen Repressionmentioning

confidence: 88%

“…In contrast with S. cerevisiae, which has two TOR proteins, only a single TOR ortholog was identified in filamentous ascomycetes such as A. nidulans, F. fujikuroi, and Podospora anserina (Dementhon et al, 2003;Fitzgibbon et al, 2005;Teichert et al, 2006 (Poulter et al, 2003). The predicted TOR1b gene product contains three of the four N-terminal HEAT (huntingtin, elongation factor 3, regulatory subunit A of PP2A, TOR1) repeats as well as all the other key domains of TOR proteins, including FAT (FRAP, ATM, TTRAP), FRB (FKBP12-rapamycin binding), catalytic kinase, and C-terminal FATC domains.…”

Section: Nitrogen Repression Of Invasive Growth Requires Gln Synthetamentioning

confidence: 99%

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A Nitrogen Response Pathway Regulates Virulence Functions in Fusarium oxysporum via the Protein Kinase TOR and the bZIP Protein MeaB

et al. 2010

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During infection, fungal pathogens activate virulence mechanisms, such as host adhesion, penetration and invasive growth. In the vascular wilt fungus Fusarium oxysporum, the mitogen-activated protein kinase Fmk1 is required for plant infection and controls processes such as cellophane penetration, vegetative hyphal fusion, or root adhesion. Here, we show that these virulence-related functions are repressed by the preferred nitrogen source ammonium and restored by treatment with L-methionine sulfoximine or rapamycin, two specific inhibitors of Gln synthetase and the protein kinase TOR, respectively. Deletion of the bZIP protein MeaB also resulted in nitrogen source-independent activation of virulence mechanisms. Activation of these functions did not require the global nitrogen regulator AreA, suggesting that MeaB-mediated repression of virulence functions does not act through inhibition of AreA. Tomato plants (Solanum lycopersicum) supplied with ammonium rather than nitrate showed a significant reduction in vascular wilt symptoms when infected with the wild type but not with the DmeaB strain. Nitrogen source also affected invasive growth in the rice blast fungus Magnaporthe oryzae and the wheat head blight pathogen Fusarium graminearum. We propose that a conserved nitrogen-responsive pathway might operate via TOR and MeaB to control virulence in plant pathogenic fungi.

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Section: Nitrogen Repression Of Invasive Growth Requires Gln Synthetamentioning

confidence: 58%

Section: Role Of Tor and Meab In Nitrogen Repressionmentioning

confidence: 88%

Section: Nitrogen Repression Of Invasive Growth Requires Gln Synthetamentioning

confidence: 99%

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A Nitrogen Response Pathway Regulates Virulence Functions in Fusarium oxysporum via the Protein Kinase TOR and the bZIP Protein MeaB

et al. 2010

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“…Namely, Cpp1 shares significant similarity with PPE-1 protein, which is a probable cell-shape-control PP2Ac in N. crassa (E value, 0.0) (unpublished; GenBank accession no. XM_951629), and with SitA, which is a PP2Ac involved in the TOR pathway of Aspergillus nidulans (E value, 8e-165) (Fitzgibbon et al, 2005; GenBank accession no. CAG30555).…”

Section: Resultsmentioning

confidence: 99%

Functional characterization of Fusarium verticillioides CPP1, a gene encoding a putative protein phosphatase 2A catalytic subunit

Choi

Shim

2008

Microbiology

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Fusarium verticillioides produces the mycotoxin fumonisin B 1 (FB 1 ) on maize kernels. In this study, we identified a putative protein phosphatase gene CPP1 in F. verticillioides, and investigated its role in FB 1 regulation. Previous work has shown that CPP1 expression is elevated in an FB 1 -suppressing genetic background. Thus, we hypothesized that CPP1 is negatively associated with FB 1 production. To test this hypothesis, we generated a CPP1 knockout mutant, PP179, and studied the effects of gene deletion on FB 1 biosynthesis and fungal development. PP179 showed elevated expression of FUM genes, and in turn produced higher levels of FB 1 than the wild-type progenitor. Other significant mutant phenotypes included reduced radial growth on agar plates, reduced conidia germination rates, significantly increased macroconidia formation, and hyphal swelling. To verify that these phenotypes were directly due to CPP1 deletion, we complemented PP179 with the wild-type CPP1 gene. The complemented strain PPC4 showed FUM1 expression and FB 1 production similar to that of the wild-type, providing evidence that CPP1 is negatively associated with FB 1 biosynthesis. Other PP179 phenotypes, such as macroconidiation and hyphal swelling, were also restored to that of wild-type progenitor. Furthermore, we complemented F. verticillioides PP179 strain with Neurospora crassa wild-type ppe-1 gene, demonstrating that Cpp1 and PPE-1 proteins are functionally conserved. Pleiotropic effects of CPP1 deletion led us to hypothesize that CPP1 is associated with multiple downstream signalling pathways in F. verticillioides. Identification and functional characterization of downstream Cpp1-interacting proteins are necessary to better understand the complex regulatory mechanisms associated with Cpp1.

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“…The genes AN5174 and AN7428 are orthologues of atg5 and atg7, respectively, and both are involved in the formation of autophagosomes in S. cerevisiae (Pollack et al, 2009). TipA is the orthologue of baker's yeast Tip41 (Fitzgibbon et al, 2005), which induces autophagy by inhibiting TOR signalling. Induction of Atg7 and Atg26 together with other autophagy-related genes was also observed in carbon-starved A. niger cultures (Nitsche et al, 2012).…”

Section: Programmed Cell Death During Carbon Starvationmentioning

confidence: 99%

Transcriptome changes initiated by carbon starvation in Aspergillus nidulans

et al. 2013

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Carbon starvation is a common stress for micro-organisms both in nature and in industry. The carbon starvation stress response (CSSR) involves the regulation of several important processes including programmed cell death and reproduction of fungi, secondary metabolite production and extracellular hydrolase formation. To gain insight into the physiological events of CSSR, DNA microarray analyses supplemented with real-time RT-PCR (rRT-PCR) experiments on 99 selected genes were performed. These data demonstrated that carbon starvation induced very complex changes in the transcriptome. Several genes contributing to protein synthesis were upregulated together with genes involved in the unfolded protein stress response. The balance between biosynthesis and degradation moved towards degradation in the case of cell wall, carbohydrate, lipid and nitrogen metabolism, which was accompanied by the production of several hydrolytic enzymes and the induction of macroautophagy. These processes provide the cultures with longterm survival by liberating nutrients through degradation of the cell constituents. The induced synthesis of secondary metabolites, antifungal enzymes and proteins as well as bacterial cell walldegrading enzymes demonstrated that carbon-starving fungi should have marked effects on the micro-organisms in their surroundings. Due to the increased production of extracellular and vacuolar enzymes during carbon starvation, the importance of the endoplasmic reticulum increased considerably.

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Genetic Analysis of the TOR Pathway in Aspergillus nidulans

Cited by 52 publications

References 28 publications

A Nitrogen Response Pathway Regulates Virulence Functions in Fusarium oxysporum via the Protein Kinase TOR and the bZIP Protein MeaB

A Nitrogen Response Pathway Regulates Virulence Functions in Fusarium oxysporum via the Protein Kinase TOR and the bZIP Protein MeaB

Functional characterization of Fusarium verticillioides CPP1, a gene encoding a putative protein phosphatase 2A catalytic subunit

Transcriptome changes initiated by carbon starvation in Aspergillus nidulans

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