Global gene expression during nitrogen starvation in the rice blast fungus, Magnaporthe grisea

Donofrio, NM; Oh, Yeonyee; Lundy, Robert F.; Pan, Huaqin; Brown, DE; Js, Jeong; Coughlan, Sean; Mitchell, TK; Ra, Dean

doi:10.1016/j.fgb.2006.03.005

Cited by 107 publications

(114 citation statements)

References 42 publications

(50 reference statements)

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“…Early studies established that in plantainduced genes, such as Mpg1 encoding a hydrophobin required for pathogenicity of the rice blast fungus Magnaporthe oryzae, or the avirulence gene Avr9 of the tomato pathogen Cladosporium fulvum, are strongly upregulated under conditions of nitrogen limitation (Talbot et al, 1993;Van den Ackerveken et al, 1994). In agreement with these findings, many genes identified in screens for nitrogen starvation-induced transcripts are also upregulated during plant infection (Coleman et al, 1997;Stephenson et al, 1997;Divon et al, 2005;Donofrio et al, 2006). Thus, nitrogen source seems to act as a metabolic switch to trigger expression of infection-related genes in plant pathogenic fungi.…”

Section: Introductionmentioning

confidence: 71%

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: Introductionmentioning

confidence: 71%

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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“…Many genes identified in screens for nitrogen starvation-induced transcripts are also upregulated during plant infection. 58 Thus, nitrogen source seems to act as a metabolic switch to trigger expression of infection-related genes in the rice blast fungus. However, the role of TOR in nutrient regulation of fungal virulence on plants has not been examined so far.…”

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confidence: 99%

Autophagy vitalizes the pathogenicity of pathogenic fungi

Liu

Gao

et al. 2012

Autophagy

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“…One common hypothesis is that plant pathogens are limited in nitrogen supply early in the infection process and that this limitation is an essential signal to start the infection cycle (74). This assumption is based on the observation that the expression of the C. fulvum effector Avr9 and the M. grisea pathogenicity factor Mpg1, as well as four other known M. grisea pathogenicity factors, are induced in axenic culture under N limitation (19,77,83). The expression of Avr9 is thereby under the control of the Nit2 homolog Nrf1 (67).…”

mentioning

confidence: 99%

“…The expression of Avr9 is thereby under the control of the Nit2 homolog Nrf1 (67). However, only 1 out of 9 known C. fulvum effectors, Avr9, and only 5 out of 21 known M. grisea pathogenicity factors are induced by N limitation (19,76,77,83). This implies on the one hand that cues other than N limitation play a role in starting the pathogenicity program and on the other hand that the reduced virulence observed in some Nit2 mutants is not solely an effect of reduced effector protein expression.…”

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confidence: 99%

The Ustilago maydis Nit2 Homolog Regulates Nitrogen Utilization and Is Required for Efficient Induction of Filamentous Growth

et al. 2012

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Nitrogen catabolite repression (NCR) is a regulatory strategy found in microorganisms that restricts the utilization of complex and unfavored nitrogen sources in the presence of favored nitrogen sources. In fungi, this concept has been best studied in yeasts and filamentous ascomycetes, where the GATA transcription factors Gln3p and Gat1p (in yeasts) and Nit2/AreA (in ascomycetes) constitute the main positive regulators of NCR. The reason why functional Nit2 homologs of some phytopathogenic fungi are required for full virulence in their hosts has remained elusive. We have identified the Nit2 homolog in the basidiomycetous phytopathogen Ustilago maydis and show that it is a major, but not the exclusive, positive regulator of nitrogen utilization. By transcriptome analysis of sporidia grown on artificial media devoid of favored nitrogen sources, we show that only a subset of nitrogen-responsive genes are regulated by Nit2, including the Gal4-like transcription factor Ton1 (a target of Nit2). Ustilagic acid biosynthesis is not under the control of Nit2, while nitrogen starvation-induced filamentous growth is largely dependent on functional Nit2. nit2 deletion mutants show the delayed initiation of filamentous growth on maize leaves and exhibit strongly compromised virulence, demonstrating that Nit2 is required to efficiently initiate the pathogenicity program of U. maydis.

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Global gene expression during nitrogen starvation in the rice blast fungus, Magnaporthe grisea

Cited by 107 publications

References 42 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

Autophagy vitalizes the pathogenicity of pathogenic fungi

The Ustilago maydis Nit2 Homolog Regulates Nitrogen Utilization and Is Required for Efficient Induction of Filamentous Growth

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