Stress and sexual reproduction affect the dynamics of the wheat pathogen effector AvrStb6 and strobilurin resistance.

Host resistance and fungicide treatments are cornerstones of plant-disease control. Here, we show that these treatments allow sex and modulate parenthood in the fungal wheat pathogen Zymoseptoria tritici. We demonstrate that the Z.

Fungicide-driven evolution and molecular basis of multidrug resistance in field populations of the grey mould fungus Botrytis cinerea.

The grey mould fungus Botrytis cinerea causes losses of commercially important fruits, vegetables and ornamentals worldwide. Fungicide treatments are effective for disease control, but bear the risk of resistance development. The major resistance mechanism in fungi is target protein modification resulting in reduced drug binding.

The drug transporter MgMfs1 can modulate sensitivity of field strains of the fungal wheat pathogen Mycosphaerella graminicola to the strobilurin fungicide trifloxystrobin.

Background: The major facilitator superfamily (MFS) drug transporter MgMfs1 of the wheat pathogen Mycosphaerella graminicola (Fuckel) J Schroeter is a potent multidrug transporter with high capacity to transport strobilurin fungicides in vitro. The data presented in this paper indicate that, in addition to the predominant cause of strobilurin resistance, cytochrome b G143A subsititution, MgMfs1 can play a role in sensitivity of field strains of this pathogen to trifloxystrobin.

Results: In a major part of field strains of M.

Control of Mycosphaerella graminicola on wheat seedlings by medical drugs known to modulate the activity of ATP-binding cassette transporters.

Medical drugs known to modulate the activity of human ATP-binding cassette (ABC) transporter proteins (modulators) were tested for the ability to potentiate the activity of the azole fungicide cyproconazole against in vitro growth of Mycosphaerella graminicola and to control disease development due to this pathogen on wheat seedlings. In vitro modulation of cyproconazole activity could be demonstrated in paper disk bioassays. Some of the active modulators (amitriptyline, flavanone, and phenothiazines) increased the accumulation of cyproconazole in M.

MgAtr7, a new type of ABC transporter from Mycosphaerella graminicola involved in iron homeostasis.

The ABC transporter-encoding gene MgAtr7 from the wheat pathogen Mycosphaerella graminicola was cloned based upon its high homology to ABC transporters involved in azole-fungicide sensitivity. Genomic and cDNA sequences indicated that the N-terminus of this ABC transporter contains a motif characteristic for a dityrosine/pyoverdine biosynthesis protein. This makes MgAtr7 the first member of a new class of fungal ABC transporters harboring both a transporter and a biosynthetic moiety.

MgMfs1, a major facilitator superfamily transporter from the fungal wheat pathogen Mycosphaerella graminicola, is a strong protectant against natural toxic compounds and fungicides.

MgMfs1, a major facilitator superfamily (MFS) gene from the wheat pathogenic fungus Mycosphaerella graminicola, was identified in expressed sequence tag (EST) libraries. The encoded protein has high homology to members of the drug:H(+) antiporter efflux family of MFS transporters with 14 predicted transmembrane spanners (DHA14), implicated in mycotoxin secretion and multidrug resistance. Heterologous expression of MgMfs1 in a hypersensitive Saccharomyces cerevisiae strain resulted in a strong decrease in sensitivity of this organism to a broad range of unrelated synthetic and natural toxic compounds.

MgHog1 regulates dimorphism and pathogenicity in the fungal wheat pathogen Mycosphaerella graminicola.

The dimorphic ascomycete pathogen Mycosphaerella graminicola switches from a yeastlike form to an infectious filamentous form that penetrates the host foliage through stomata. We examined the biological function of the mitogen-activated protein kinase-encoding gene MgHog1 in M. graminicola.

Impact of fungal drug transporters on fungicide sensitivity, multidrug resistance and virulence.

Drug transporters are membrane proteins that provide protection for organisms against natural toxic products and fungicides. In plant pathogens, drug transporters function in baseline sensitivity to fungicides, multidrug resistance (MDR) and virulence on host plants. This paper describes drug transporters of the filamentous fungi Aspergillus nidulans (Eidam) Winter, Botrytis cinerea Pers and Mycosphaerella graminicola (Fückel) Schroter that function in fungicide sensitivity and resistance.

Multiple mechanisms account for variation in base-line sensitivity to azole fungicides in field isolates of Mycosphaerella graminicola.

Molecular mechanisms that account for variation in base-line sensitivity to azole fungicides were examined in a collection of twenty field isolates, collected in France and Germany, of the wheat pathogen Mycosphaerella graminicola (Fuckel) Schroeter. The isolates tested represent the wide baseline sensitivity to the azole fungicide tebuconazole described previously. The isolates were cross-sensitive to other azoles tested, such as cyproconazole and ketoconazole, but not to unrelated chemicals like cycloheximide, kresoxim-methyl or rhodamine 6G.

The ABC transporter MgAtr4 is a virulence factor of Mycosphaerella graminicola that affects colonization of substomatal cavities in wheat leaves.

The role in virulence of the ATP-binding cassette (ABC) transporters MgAtr1, MgAtr2, MgAtr3, MgAtr4, and MgAtr5 from Mycosphaerella graminicola was analyzed by gene disruption or replacement on seedlings of the susceptible wheat cultivar Obelisk. Disruption strains of MgAtr1 and MgAtr2 and replacement strains of MgAtr3 and MgAtr5 displayed the same phenotype as control strains, while virulence of the MgAtr4 disruption strains was significantly reduced. This reduction in virulence was independent of the wheat cultivar used.

Modulators of membrane drug transporters potentiate the activity of the DMI fungicide oxpoconazole against Botrytis cinerea.

Modulators known to reduce multidrug resistance in tumour cells were tested for their potency to synergize the fungitoxic activity of the fungicide oxpoconazole, a sterol demethylation inhibitor (DMI), against Botrytis cinerea Pers. Chlorpromazine, a phenothiazine compound known as a calmodulin antagonist, appeared the most potent compound. Tacrolimus, a macrolide compound with immunosuppressive activity, was also active.

ABC transporters and azole susceptibility in laboratory strains of the wheat pathogen Mycosphaerella graminicola.

Laboratory strains of Mycosphaerella graminicola with decreased susceptibilities to the azole antifungal agent cyproconazole showed a multidrug resistance phenotype by exhibiting cross-resistance to an unrelated chemical, cycloheximide or rhodamine 6G, or both. Decreased azole susceptibility was found to be associated with either decreased or increased levels of accumulation of cyproconazole. No specific relationship could be observed between azole susceptibility and the expression of ATP-binding cassette (ABC) transporter genes MgAtr1 to MgAtr5 and the sterol P450 14alpha-demethylase gene, CYP51.

Fungal ABC transporters and microbial interactions in natural environments.

In natural environments, microorganisms are exposed to a wide variety of antibiotic compounds produced by competing organisms. Target organisms have evolved various mechanisms of natural resistance to these metabolites. In this study, the role of ATP-binding cassette (ABC) transporters in interactions between the plant-pathogenic fungus Botrytis cinerea and antibiotic-producing Pseudomonas bacteria was investigated in detail.

Bcmfs1, a novel major facilitator superfamily transporter from Botrytis cinerea, provides tolerance towards the natural toxic compounds camptothecin and cercosporin and towards fungicides.

Bcmfs1, a novel major facilitator superfamily gene from Botrytis cinerea, was cloned, and replacement and overexpression mutants were constructed to study its function. Replacement mutants showed increased sensitivity to the natural toxic compounds camptothecin and cercosporin, produced by the plant Camptotheca acuminata and the plant pathogenic fungus Cercospora kikuchii, respectively. Overexpression mutants displayed decreased sensitivity to these compounds and to structurally unrelated fungicides, such as sterol demethylation inhibitors (DMIs).

Isolation and characterization of the mating-type idiomorphs from the wheat septoria leaf blotch fungus Mycosphaerella graminicola.

Both mating-type loci from the wheat septoria leaf blotch pathogen Mycosphaerella graminicola have been cloned and sequenced. The MAT1-2 gene was identified by screening a genomic library from the MAT1-2 isolate IPO94269 with a heterologous probe from Tapesia yallundae. The MAT1-2 idiomorph is 2772 bp and contains a single gene encoding a putative high-mobility-group protein of 394 amino acids.

The ABC transporter AtrB from Aspergillus nidulans mediates resistance to all major classes of fungicides and some natural toxic compounds.

This paper reports the functional characterization of AtrBp, an ABC transporter from Aspergillus nidulans. AtrBp is a multidrug transporter and has affinity to substrates belonging to all major classes of agricultural fungicides and some natural toxic compounds. The substrate profile of AtrBp was determined by assessing the sensitivity of deletion and overexpression mutants of atrB to several toxicants.