The pH regulatory factor Pac1 regulates Tri gene expression and trichothecene production in Fusarium graminearum

Merhej, Jawad; Richard‐Forget, Florence; Barreau, Christian

doi:10.1016/j.fgb.2010.11.008

Cited by 113 publications

(130 citation statements)

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“…Reduced nitrogen sources such as the amines putrescine and arginine in combination with a low pH are also excellent in vitro inducers of DON production (Gardiner et al, 2009a(Gardiner et al, , 2009cMerhej et al, 2011). Putrescine and arginine accumulate in F. graminearum infected wheat heads (Gardiner et al, 2010) and their biosynthesis is known to be upregulated in plants during defence responses (Haggag and Abd-El-Kareem, 2009;Walters, 2002).…”

Section: Introductionmentioning

confidence: 99%

High-throughput FACS-based mutant screen identifies a gain-of-function allele of the Fusarium graminearum adenylyl cyclase causing deoxynivalenol over-production

Blum

Benfield

Stiller

et al. 2016

Fungal Genetics and Biology

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., High-throughput FACS-based mutant screen identifies a gain-of-function allele of the Fusarium graminearum adenylyl cyclase causing deoxynivalenol over-production, Fungal Genetics and Biology (2016), doi: http://dx.doi. org/10.1016/j.fgb. 2016.02.005 This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. ABSTRACTFusarium head blight and crown rot, caused by the fungal plant pathogen Fusarium graminearum, impose a major threat to global wheat production. During the infection, plants are contaminated with mycotoxins such as deoxynivalenol (DON), which can be toxic for humans and animals. In addition, DON is a major virulence factor during wheat infection. However, it is not fully understood how DON production is regulated in F. graminearum. In order to identify regulators of DON production, a high-throughput mutant screen using Fluorescence Activated Cell Sorting (FACS) of a mutagenized TRI5-GFP reporter strain was established and a mutant over-producing DON under repressive conditions identified. A gain-of-function mutation in the F. graminearum adenylyl cyclase (FAC1), which is a known positive regulator of DON production, was identified as the cause of this phenotype through genome sequencing and segregation analysis. Our results show that the high-throughput mutant screening procedure developed here can be applied for identification of fungal proteins involved in diverse processes.

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Section: Introductionmentioning

confidence: 99%

High-throughput FACS-based mutant screen identifies a gain-of-function allele of the Fusarium graminearum adenylyl cyclase causing deoxynivalenol over-production

Blum

Benfield

Stiller

et al. 2016

Fungal Genetics and Biology

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“…Under alkaline conditions, PacC upregulates some alkaline pH inducible genes but prevents expression of acid-expressed genes (Then Bergh et al, 1998;Cupertino et al, 2012;Espeso & Arst, 2000;Kanda et al, 2008;Merhej et al, 2011;Tilburn et al, 1995). The transcription of the PacC gene is self-regulated in a feedback manner.…”

Section: Discussionmentioning

confidence: 99%

Expression and promoter characterization of BbPacC, a pH response transcription factor gene of the entomopathogenic fungus Beauveria bassiana

et al. 2014

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To survive, the entomopathogenic fungus Beauveria bassiana, which shows promise as a biocontrol agent for a variety of pests, including agricultural and forestry pests and vectors of human pathogens, must tailor gene expression to the particular pH of its environment. The pH response transcription factor gene BbPacC and its flanking sequence were cloned from this fungus. Quantitative reverse transcription (RT)-PCR revealed that it is highly induced by alkaline pH and salt stress, and the expression level achieved twice that of the housekeeping gene c-actin. A microfluorometric assay indicated that the 1479 bp promoter region could activate the expression of enhanced green fluorescent protein (EGFP) under the same conditions. Truncation analysis showed that the 1479, 1274, 1040, 888 and 742 bp promoters have similar efficiencies in activating expression of b-glucuronidase (GUS). The GUS activities of corresponding transformants reached approximately 50 % that of those containing the strong constitutive promoter PtrpC. A truncation upstream at the -572 bp position (referenced to the translation start codon ATG), however, resulted in a significant loss of GUS activity. Both the upstream absences of the "502 and "387 bp positions caused almost complete loss of GUS activity. These results suggest that PPacC is an efficient, alkaline, and salt-inducible promoter, the core cis-elements are mainly located within the -742 to -502 bp region, and promoters equal to or longer than 742 bp may be feasible for regulating gene expression in response to an ambient pH or salt stress.

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“…Further proteins ranging from lyases, to lipases and phosphatases have also been reported as positive regulators and are summarized in Table 1.2. PAC1 -pH regulatory factor induced earlier transcription (Merhej et al, 2011) In summary, there are a great number of abiotic factors and regulatory mechanisms which influence DON production ( Figure 1.5). Most of these regulators not only influence the production of DON, but also developmental programs required for pathogenicity of F. graminearum and for vegetative or sexual production (reviewed in Geng et al 2014).…”

Section: Fusariummentioning

confidence: 94%

“…In F. graminearum, the DON production inducing effects of low pH conditions seem to be mediated by the PacC homologue FgPac1, because a ∆Fgpac1 knockout mutant induced DON production earlier under acidic conditions and a constitutively active FgPac1 c mutant repressed DON production (Merhej et al, 2011).…”

Section: Fusariummentioning

confidence: 99%

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Regulation and cell biology of secondary metabolite production in Fusarium graminearum and Fusarium pseudograminearum

Blum¹

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1 AbstractAscomycete fungi have the potential to produce a vast array of secondary metabolites, which are metabolites not required for normal growth and development. In any one species there is typically the potential for production of upward of fifty of these compounds. Many fungal secondary metabolites are used as medicines (e.g. penicillin or cyclosporine), or are of importance due to their toxicity in humans or animals (e.g. aflatoxins), or because they are virulence factors during crop plant infection (e.g. deoxynivalenol). Despite the vast potential encoded in ascomycete genomes, the vast majority of fungal secondary metabolites are yet to be discovered. This is in part due to our lack of understanding of how the production of these compounds is regulated. Moreover, even for the compounds we do know, we are just beginning to understand the complex interaction of external stimuli, signalling pathways, cellular and developmental biology that leads to their production. In this thesis, biological insights into these aspects of two fungal secondary metabolites, deoxynivalenol (DON) and fusatin are provided.In chapter II a high-throughput fluorescence activated cell sorting (FACS) based mutant screen was developed and the regulation of DON production in Fusarium graminearum was analysed. DON is an economically very important mycotoxin, as it is the most common contaminant of wheat, barley and corn worldwide. It is produced by plant pathogenic filamentous fungi of the Fusarium family, which can cause Fusarium head blight as well as Fusarium crown rot. During plant infection, DON is an important virulence factor and it can be toxic for humans and animals. The regulation of DON production is not yet fully understood. To identify regulators, a mutant screen was developed using FACS to allow high throughput screening, coupled with whole genome sequencing to identify mutations.Segregation analyses were performed to determine the mutation causing the phenotype.The mutant screen identified an adenylyl cyclase allele, which resulted in production of DON under normally repressive conditions. In addition, the mutant developed cellular structures associated with toxin production under repressive conditions. The levels of the fundamental second messenger cAMP, which adenylyl cyclases produce, were increased in the identified mutant, suggesting it might be a gain-of-function adenylyl cyclase mutant. This mutant screening methodology can be adapted to identify regulators of different secondary metabolites as well as to identify mutants overproducing yet unknown secondary metabolites. Abstract 2In chapter III the cell biology of DON production in Fusarium graminearum was elucidated with quantitative super resolution microscopy. During the last five years the first insights into the cell biology of DON production were gained, indicating complex cell biological mechanisms. During toxin production, F. graminearum develops endoplasmic reticulum proliferations, called toxisomes, at which two DON biosynthesis enzymes, TRI1 a...

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The pH regulatory factor Pac1 regulates Tri gene expression and trichothecene production in Fusarium graminearum

Cited by 113 publications

References 55 publications

High-throughput FACS-based mutant screen identifies a gain-of-function allele of the Fusarium graminearum adenylyl cyclase causing deoxynivalenol over-production

High-throughput FACS-based mutant screen identifies a gain-of-function allele of the Fusarium graminearum adenylyl cyclase causing deoxynivalenol over-production

Expression and promoter characterization of BbPacC, a pH response transcription factor gene of the entomopathogenic fungus Beauveria bassiana

Regulation and cell biology of secondary metabolite production in Fusarium graminearum and Fusarium pseudograminearum

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