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1.
PLoS One ; 19(2): e0297816, 2024.
Article in English | MEDLINE | ID: mdl-38319941

ABSTRACT

In their natural environment, fungi are subjected to a wide variety of environmental stresses which they must cope with by constantly adapting the architecture of their growing network. In this work, our objective was to finely characterize the thallus development of the filamentous fungus Podospora anserina subjected to different constraints that are simple to implement in vitro and that can be considered as relevant environmental stresses, such as a nutrient-poor environment or non-optimal temperatures. At the Petri dish scale, the observations showed that the fungal thallus is differentially affected (thallus diameter, mycelium aspect) according to the stresses but these observations remain qualitative. At the hyphal scale, we showed that the extraction of the usual quantities (i.e. apex, node, length) does not allow to distinguish the different thallus under stress, these quantities being globally affected by the application of a stress in comparison with a thallus having grown under optimal conditions. Thanks to an original geomatics-based approach based on the use of automatized Geographic Information System (GIS) tools, we were able to produce maps and metrics characterizing the growth dynamics of the networks and then to highlight some very different dynamics of network densification according to the applied stresses. The fungal thallus is then considered as a map and we are no longer interested in the quantity of material (hyphae) produced but in the empty spaces between the hyphae, the intra-thallus surfaces. This study contributes to a better understanding of how filamentous fungi adapt the growth and densification of their network to potentially adverse environmental changes.


Subject(s)
Podospora , Fungi , Hyphae , Mycelium , Stress, Physiological , Fungal Proteins
2.
J Fungi (Basel) ; 10(1)2024 Jan 19.
Article in English | MEDLINE | ID: mdl-38276025

ABSTRACT

The ascomycete Podospora anserina is a heterothallic filamentous fungus found mainly on herbivore dung. It is commonly used in laboratories as a model system, and its complete life cycle lasting eight days is well mastered in vitro. The main objective of our team is to understand better the global process of fruiting body development, named perithecia, induced normally in this species by fertilization. Three allelic mutants, named pfd3, pfd9, and pfd23 (for "promoting fruiting body development") obtained by UV mutagenesis, were selected in view of their abilities to promote barren perithecium development without fertilization. By complete genome sequencing of pfd3 and pfd9, and mutant complementation, we identified point mutations in the mcm1 gene as responsible for spontaneous perithecium development. MCM1 proteins are MADS box transcription factors that control diverse developmental processes in plants, metazoans, and fungi. We also identified using the same methods a mutation in the VelC gene as responsible for spontaneous perithecium development in the vacua mutant. The VelC protein belongs to the velvet family of regulators involved in the control of development and secondary metabolite production. A key role of MCM1 and VelC in coordinating the development of P. anserina perithecia with gamete formation and fertilization is highlighted.

3.
Sci Rep ; 13(1): 8501, 2023 05 25.
Article in English | MEDLINE | ID: mdl-37231023

ABSTRACT

Under ideal conditions, the growth of the mycelial network of a filamentous fungus is monotonous, showing an ever increasing complexity with time. The components of the network growth are very simple and based on two mechanisms: the elongation of each hypha, and their multiplication by successive branching. These two mechanisms are sufficient to produce a complex network, and could be localized only at the tips of hyphae. However, branching can be of two types, apical or lateral, depending on its location on the hyphae, therefore imposing the redistribution of the necessary material in the whole mycelium. From an evolutionary point of view, maintaining different branching processes, with additional energy needs for structure and metabolism, is intriguing. We propose in this work to discuss the advantages of each branching type using a new observable for the network growth, allowing us to compare growth configurations. For this purpose, we build on experimental observations of the Podospora anserina mycelium growth, enabling us to feed and constrain a lattice-free modeling of this network based on a binary tree. First, we report the set of statistics related to the branches of P. anserina that we have implemented into the model. Then, we build the density observable, allowing us to discuss the succession of growth phases. We predict that density over time is not monotonic, but shows a decay growth phase, clearly separated from an other one by a stationary phase. The time of appearance of this stable region appears to be driven solely by the growth rate. Finally, we show that density is an appropriate observable to differentiate growth stress.


Subject(s)
Hyphae , Podospora , Mycelium , Fungi/metabolism , Fungal Proteins/metabolism
4.
Adv Pharm Bull ; 12(4): 747-756, 2022 Aug.
Article in English | MEDLINE | ID: mdl-36415634

ABSTRACT

Cancer is a serious debilitating disease and one of the most common causes of death. In recent decades the high risk of various cancers enforced scientists to discover novel prevention and treatment methods to diminish the mortality of this terrifying disease. Accordingly, its prevention can be possible in near future. Based on epidemiological evidence, there is a clear link between pathogenic fungal infections and cancer development. This association is often seen in people with weakened immune systems such as the elderly and people with acquired immunodeficiency (AIDS). Carcinoma in these people is first seen chronically and then acutely. Although the different genetic and environmental risk factors are involved in carcinogenesis, one of the most important risk factors is fungal species and infections associating with cancers etiology. Now it is known that microbial infection is responsible for initiating 2.2 million new cancer cases. In this way, many recent studies have focused on investigating the role and mechanism of fungal infections in diverse cancers occurrence. This review provides a comprehensive framework of the latest clinical findings and the association of fungal infections with versatile cancers including esophageal, gastric, colorectal, lung, cervical, skin, and ovarian cancer.

5.
Sci Rep ; 12(1): 12351, 2022 07 19.
Article in English | MEDLINE | ID: mdl-35853921

ABSTRACT

Based upon apical growth and hyphal branching, the two main processes that drive the growth pattern of a fungal network, we propose here a two-dimensions simulation based on a binary-tree modelling allowing us to extract the main characteristics of a generic thallus growth. In particular, we showed that, in a homogeneous environment, the fungal growth can be optimized for exploration and exploitation of its surroundings with a specific angular distribution of apical branching. Two complementary methods of extracting angle values have been used to confront the result of the simulation with experimental data obtained from the thallus growth of the saprophytic filamentous fungus Podospora anserina. Finally, we propose here a validated model that, while being computationally low-cost, is powerful enough to test quickly multiple conditions and constraints. It will allow in future works to deepen the characterization of the growth dynamic of fungal network, in addition to laboratory experiments, that could be sometimes expensive, tedious or of limited scope.


Subject(s)
Podospora , Fungal Proteins , Fungi , Hyphae
6.
Environ Microbiol ; 24(7): 2907-2923, 2022 07.
Article in English | MEDLINE | ID: mdl-35315561

ABSTRACT

Light serves as a source of information and regulates diverse physiological processes in living organisms. Fungi perceive and respond to light through a complex photosensory system. Fungi have evolved the desensitization mechanism to adapt to the changing light signal in a natural environment. White light exerts multiple essential impacts on the model filamentous fungus Podospora anserina. However, the light sensing and response in this species has not been investigated. In this study, we demonstrated that the loss of function of the light desensitization protein VIVID (VVD) in P. anserina triggered exacerbated light responses and therefore led to drastic morphological and physiological changes. The white light-sensitive mutant Δvvd showed growth reduction, spermatia overproduction, enhanced hyphae pigmentation and reduced oxidative stress tolerance. We observed the decreased expression level of sterigmatocystin gene cluster by transcriptome analysis and finally detected the reduced production of sterigmatocystin in Δvvd in response to white light. Our data indicate that VVD acts as a repressor of white collar complex. This study exhibits a vital role of VVD in governing white light-responsive gene expression and secondary metabolite production and contributes to a better understanding of the photoreceptor VVD in P. anserina.


Subject(s)
Podospora , Fungal Proteins/metabolism , Fungi/metabolism , Pigmentation/genetics , Podospora/genetics , Sexual Development , Sterigmatocystin
7.
BMC Complement Med Ther ; 22(1): 78, 2022 Mar 19.
Article in English | MEDLINE | ID: mdl-35305633

ABSTRACT

BACKGROUND: Multi-drug resistant bacteria hazards to the health of humans could be an agent in the destruction of human generation. Natural products of Bacillus species are the main source to access progressive antibiotics that can be a good candidate for the discovery of novel antibiotics. Wild honey as a valuable food has been used in medicine with antimicrobial effects. OBJECTIVE: Bacillus strains isolated from wild honey were evaluated for the potential antimicrobial activity against human and plant bacterial and fungal pathogens. METHODS: Three bacterial isolates were identified as strain Khuz-1 (98.27% similarity with Bacillus safensis subsp. Safensis strain FO-36bT), strain Khuz-2 (99.18% similarity with Bacillus rugosus strain SPB7T), and strain Khuz-3 (99.78% similarity with Bacillus velezensis strain CR-502 T) by 16S rRNA gene sequences. The strains were characterized by their ability to inhibit the growth of human and phytopathogenic fungi. RESULTS: The results indicated that B. rugosus strain Khuz-2 inhibited the growth of phytopathogenic and human fungal more effective than other ones. It seems that the strain Khuz-2 has a suitable antimicrobial and antifungal potential as a good candidate for further pharmaceutical research. CONCLUSION: Based on the results of GC-MS, Pyrrolo [1,2-a] pyrazine-1,4-dion, hexahydro-3-(2-methylpropyle) (PPDHM) was the major compound for all strains which have a various pharmacological effect. Isolation and identification of beneficial bacteria from natural sources can play an important role in future pharmaceutical and industrial applications.


Subject(s)
Anti-Infective Agents , Bacillus , Honey , Anti-Infective Agents/pharmacology , Bacillus/genetics , Fungi , Humans , RNA, Ribosomal, 16S
8.
Appl Environ Microbiol ; 88(6): e0237821, 2022 03 22.
Article in English | MEDLINE | ID: mdl-35080910

ABSTRACT

The model ascomycete Podospora anserina, distinguished by its strict sexual development, is a prolific but yet unexploited reservoir of natural products. The GATA-type transcription factor NsdD has been characterized by the role in balancing asexual and sexual reproduction and governing secondary metabolism in filamentous fungi. In the present study, we functionally investigated the NsdD ortholog PaNsdD in P. anserina. Compared to the wild-type strain, vegetative growth, ageing processes, sexual reproduction, stress tolerance, and interspecific confrontations in the mutant were drastically impaired, owing to the loss of function of PaNsdD. In addition, the production of 3-acetyl-4-methylpyrrole, a new metabolite identified in P. anserina in this study, was significantly inhibited in the ΔPaNsdD mutant. We also demonstrated the interplay of PaNsdD with the sterigmatocystin biosynthetic gene pathway, especially as the deletion of PaNsdD triggered the enhanced red-pink pigment biosynthesis that occurs only in the presence of the core polyketide synthase-encoding gene PaStcA of the sterigmatocystin pathway. Taken together, these results contribute to a better understanding of the global regulation mediated by PaNsdD in P. anserina, especially with regard to its unexpected involvement in the fungal ageing process and its interplay with the sterigmatocystin pathway. IMPORTANCE Fungal transcription factors play an essential role in coordinating multiple physiological processes. However, little is known about the functional characterization of transcription factors in the filamentous fungus Podospora anserina. In this study, a GATA-type regulator PaNsdD was investigated in P. anserina. The results showed that PaNsdD was a key factor that can control the fungal ageing process, vegetative growth, pigmentation, stress response, and interspecific confrontations and positively regulate the production of 3-acetyl-4-methylpyrrole. Meanwhile, a molecular interaction was implied between PaNsdD and the sterigmatocystin pathway. Overall, loss of function of PaNsdD seems to be highly disadvantageous for P. anserina, which relies on pure sexual reproduction in a limited life span. Therefore, PaNsdD is clearly indispensable for the survival and propagation of P. anserina in its complex ecological niches.


Subject(s)
Podospora , Fungal Proteins/genetics , Fungal Proteins/metabolism , Fungi/metabolism , GATA Transcription Factors/metabolism , Podospora/genetics , Podospora/metabolism , Sterigmatocystin/metabolism , Transcription Factors/genetics , Transcription Factors/metabolism
9.
J Fungi (Basel) ; 9(1)2022 Dec 21.
Article in English | MEDLINE | ID: mdl-36675830

ABSTRACT

The coprophilous ascomycete Podospora anserina is known to have a high potential to synthesize a wide array of secondary metabolites (SMs). However, to date, the characterization of SMs in this species, as in other filamentous fungal species, is far less than expected by the functional prediction through genome mining, likely due to the inactivity of most SMs biosynthesis gene clusters (BGCs) under standard conditions. In this work, our main objective was to compare the global strategies usually used to deregulate SM gene clusters in P. anserina, including the variation of culture conditions and the modification of the chromatin state either by genetic manipulation or by chemical treatment, and to show the complementarity of the approaches between them. In this way, we showed that the metabolomics-driven comparative analysis unveils the unexpected diversity of metabolic changes in P. anserina and that the integrated strategies have a mutual complementary effect on the expression of the fungal metabolome. Then, our results demonstrate that metabolite production is significantly influenced by varied cultivation states and epigenetic modifications. We believe that the strategy described in this study will facilitate the discovery of fungal metabolites of interest and will improve the ability to prioritize the production of specific fungal SMs with an optimized treatment.

10.
BMC Complement Med Ther ; 21(1): 64, 2021 Feb 15.
Article in English | MEDLINE | ID: mdl-33588819

ABSTRACT

BACKGROUND: The disparity of harvesting locations can influence the chemical composition of a plant species, which could affect its quality and bioactivity. Terminalia albida is widely used in traditional Guinean medicine whose activity against malaria has been validated in vitro and in murine models. The present work investigated the antimalarial properties and chemical composition of two samples of T. albida collected from different locations in Guinea. METHOD: T. albida samples were collected in different locations in Guinea, in Dubréka prefecture (West maritime Guinea) and in Kankan prefecture (eastern Guinea). The identity of the samples was confirmed by molecular analysis. In vitro antiplasmodial activity of the two extracts was determined against the chloroquine resistant strain PfK1. In vivo, extracts (100 mg/kg) were tested in two experimental murine models, respectively infected with P. chabaudi chabaudi and P. berghei ANKA. The chemical composition of the two samples was assessed by ultra-high-performance liquid chromatography coupled to high resolution mass spectrometry. RESULTS: In vitro, the Dubréka sample (TaD) was more active with an IC50 of 1.5 µg/mL versus 8.5 µg/mL for the extract from Kankan (TaK). In vivo, the antiparasitic effect of TaD was substantial with 56% of parasite inhibition at Day 10 post-infection in P. chabaudi infection and 61% at Day 8 in P. berghei model, compared to 14 and 19% inhibition respectively for the treatment with TaK. In addition, treatment with TaD further improved the survival of P. berghei infected-mice by 50% at Day 20, while the mortality rate of mice treated with Tak was similar to the untreated group. The LC/MS analysis of the two extracts identified 38 compounds, 15 of which were common to both samples while 9 and 14 other compounds were unique to TaD and TaK respectively. CONCLUSION: This study highlights the variability in the chemical composition of the species T. albida when collected in different geographical locations. These chemical disparities were associated with variable antimalarial effects. From a public health perspective, these results underline the importance of defining chemical fingerprints related to botanical species identification and to biological activity, for the plants most commonly used in traditional medicine.


Subject(s)
Antimalarials/chemistry , Malaria/drug therapy , Phytotherapy , Plant Extracts/chemistry , Plasmodium/drug effects , Terminalia/chemistry , Animals , Antimalarials/pharmacology , Antimalarials/therapeutic use , Female , Guinea , Malaria/parasitology , Male , Medicine, African Traditional , Mice, Inbred C57BL , Plant Extracts/pharmacology , Plant Extracts/therapeutic use , Species Specificity , Terminalia/classification
11.
Environ Microbiol ; 21(8): 3011-3026, 2019 08.
Article in English | MEDLINE | ID: mdl-31136075

ABSTRACT

Filamentous fungi are known as prolific untapped reservoirs of diverse secondary metabolites, where genes required for their synthesis are organized in clusters. The bioactive properties of these compounds are closely related to their functions in fungal biology, which are not well understood. In this study, we focused on the Podospora anserina gene cluster responsible for the biosynthesis of sterigmatocystin (ST). Deletion of the PaStcA gene encoding the polyketide synthase and overexpression (OE) of the PaAflR gene encoding the ST-specific transcription factor in P. anserina were performed. We showed that growth of PaStcAΔ was inhibited in the presence of methylglyoxal, while OE-PaAflR showed a little inhibition, indicating that ST production may enhance oxidative stress tolerance in P. anserina. We also showed that the OE-PaAflR strain displayed an overpigmented thallus mediated by the melanin pathway. Overexpression of PaAflR also led to sterility. Interspecific confrontation assays showed that ST-overexpressed strains produced a high level of peroxides and possessed a higher competitiveness against other fungi. Comparative metabolite profiling demonstrated that PaStcAΔ strain was unable to produce ST, while OE-PaAflR displayed a ST overproduction. This study contributes to a better understanding of ST in P. anserina, especially with regard to its involvement in fungal physiology.


Subject(s)
Oxidative Stress , Pigmentation , Podospora/physiology , Sterigmatocystin/metabolism , Ecology , Fungal Proteins/genetics , Fungi/genetics , Gene Expression Regulation, Fungal , Multigene Family , Polyketide Synthases/genetics , Sequence Deletion , Species Specificity , Transcription Factors/genetics
12.
Fungal Genet Biol ; 116: 1-13, 2018 07.
Article in English | MEDLINE | ID: mdl-29654834

ABSTRACT

The Podospora anserina genome contains a large family of 15 multicopper oxidases (MCOs), including three genes encoding a FET3-like protein, an ABR1-like protein and an ascorbate oxidase (AO)-like protein. FET3, ABR1 and AO1 are involved in global laccase-like activity since deletion of the relevant genes led to a decrease of activity when laccase substrate (ABTS) was used as substrate. However, contrary to the P. anserina MCO proteins previously characterized, none of these three MCOs seemed to be involved in lignocellulose degradation and in resistance to phenolic compounds and oxidative stress. We showed that the bulk of ferroxidase activity was clearly due to ABR1, and only in minor part to FET3, although ABR1 does not contain all the residues typical of FET3 proteins. Moreover, we showed that ABR1, related to the Aspergillus fumigatus ABR1 protein, was clearly and specifically involved in pigmentation of ascospores. Surprisingly, phenotypes were more severe in mutants lacking both abr1 and ao1. Deletion of the ao1 gene led to an almost total loss of AO activity. No direct involvement of AO1 in fungal developmental process in P. anserina was evidenced, except in a abr1Δ background. Overall, unlike other previously characterized MCOs, we thus evidence a clear involvement of ABR1 protein in fungal development.


Subject(s)
Fungal Proteins/metabolism , Oxidoreductases/metabolism , Podospora/enzymology , Copper/chemistry , Lignin/metabolism , Oxidoreductases/chemistry , Podospora/growth & development , Spores, Fungal
13.
Dev Biol ; 429(1): 285-305, 2017 09 01.
Article in English | MEDLINE | ID: mdl-28629791

ABSTRACT

The molecular pathways involved in the development of multicellular fruiting bodies in fungi are still not well known. Especially, the interplay between the mycelium, the female tissues and the zygotic tissues of the fruiting bodies is poorly documented. Here, we describe PM154, a new strain of the model ascomycetes Podospora anserina able to mate with itself and that enabled the easy recovery of new mutants affected in fruiting body development. By complete genome sequencing of spod1, one of the new mutants, we identified an inositol phosphate polykinase gene as essential, especially for fruiting body development. A factor present in the wild type and diffusible in mutant hyphae was able to induce the development of the maternal tissues of the fruiting body in spod1, but failed to promote complete development of the zygotic ones. Addition of myo-inositol in the growth medium was able to increase the number of developing fruiting bodies in the wild type, but not in spod1. Overall, the data indicated that inositol and inositol polyphosphates were involved in promoting fruiting body maturation, but also in regulating the number of fruiting bodies that developed after fertilization. The same effect of inositol was seen in two other fungi, Sordaria macrospora and Chaetomium globosum. Key role of the inositol polyphosphate pathway during fruiting body maturation appears thus conserved during the evolution of Sordariales fungi.


Subject(s)
Inositol Phosphates/metabolism , Podospora/growth & development , Podospora/metabolism , Signal Transduction , Amino Acid Sequence , Cell Nucleus/metabolism , Fertility , Fruiting Bodies, Fungal/metabolism , Fungal Proteins/chemistry , Fungal Proteins/metabolism , Genes, Fungal , Green Fluorescent Proteins/metabolism , Inositol/metabolism , MAP Kinase Signaling System , Mosaicism , Mutation/genetics , Phenotype , Pigments, Biological/metabolism , Podospora/enzymology , Podospora/genetics , Protein Transport , Reproduction , Sordariales/metabolism , Spores, Fungal/metabolism , Temperature , Zygote/metabolism
14.
Environ Microbiol ; 17(3): 866-75, 2015 Mar.
Article in English | MEDLINE | ID: mdl-24947769

ABSTRACT

Plant biomass degradation by fungi is a critical step for production of biofuels, and laccases are common ligninolytic enzymes envisioned for ligninolysis. Bilirubin oxidases (BODs)-like are related to laccases, but their roles during lignocellulose degradation have not yet been fully investigated. The two BODs of the ascomycete fungus Podospora anserina were characterized by targeted gene deletions. Enzymatic assay revealed that the bod1(Δ) and bod2(Δ) mutants lost partly a thermostable laccase activity. A triple mutant inactivated for bod1, bod2 and mco, a previously investigated multicopper oxidase gene distantly related to laccases, had no thermostable laccase activity. The pattern of fruiting body production in the bod1(Δ) bod2(Δ) double mutant was changed. The bod1(Δ) and bod2(Δ) mutants were reduced in their ability to grow on ligneous and cellulosic materials. Furthermore, bod1(Δ) and bod2(Δ) mutants were defective towards resistance to phenolic substrates and H2 O2 , which may also impact lignocellulose breakdown. Double and triple mutants were more affected than single mutants, evidencing redundancy of function among BODs and mco. Overall, the data show that bod1, bod2 and mco code for non-canonical thermostable laccases that participate in the degradation of lignocellulose. Thanks to their thermal stability, these enzymes may be more promising candidate for biotechnological application than canonical laccases.


Subject(s)
Biofuels , Fungal Proteins/metabolism , Lignin/metabolism , Oxidoreductases Acting on CH-CH Group Donors/metabolism , Podospora/enzymology , Amino Acid Sequence , Biotechnology/methods , Fungal Proteins/genetics , Gene Deletion , Laccase/genetics , Oxidative Stress , Oxidoreductases/genetics , Oxidoreductases Acting on CH-CH Group Donors/genetics , Plants/metabolism , Sequence Alignment , Sequence Deletion/genetics
15.
Environ Microbiol ; 16(1): 141-61, 2014 Jan.
Article in English | MEDLINE | ID: mdl-24102726

ABSTRACT

Transformation of plant biomass into biofuels may supply environmentally friendly alternative biological sources of energy. Laccases are supposed to be involved in the lysis of lignin, a prerequisite step for efficient breakdown of cellulose into fermentable sugars. The role in development and plant biomass degradation of the nine canonical laccases belonging to three different subfamilies and one related multicopper oxidase of the Ascomycota fungus Podospora anserina was investigated by targeted gene deletion. The 10 genes were inactivated singly, and multiple mutants were constructed by genetic crosses. lac6(Δ), lac8(Δ) and mco(Δ) mutants were significantly reduced in their ability to grow on lignin-containing materials, but also on cellulose and plastic. Furthermore, lac8(Δ), lac7(Δ), mco(Δ) and lac6(Δ) mutants were defective towards resistance to phenolic substrates and H2 O2 , which may also impact lignocellulose breakdown. Double and multiple mutants were generally more affected than single mutants, evidencing redundancy of function among laccases. Our study provides the first genetic evidences that laccases are major actors of wood utilization in a fungus and that they have multiple roles during this process apart from participation in lignin lysis.


Subject(s)
Fungal Proteins/metabolism , Gene Deletion , Laccase/metabolism , Podospora/enzymology , Wood/microbiology , Cellulose/metabolism , Fungal Proteins/genetics , Laccase/genetics , Lignin/metabolism , Multigene Family , Mutation , Phylogeny , Podospora/classification , Podospora/genetics , Podospora/metabolism , Wood/metabolism
16.
Fungal Genet Biol ; 52: 1-8, 2013 Mar.
Article in English | MEDLINE | ID: mdl-23268147

ABSTRACT

Chitin synthases play critical roles in hyphal development and fungal pathogenicity. Previous studies on Botrytis cinerea, a model organism for necrotrophic pathogens, have shown that disruption of Bcchs1 and more particularly Bcchs3a genes have a drastic impact on virulence (Soulié et al., 2003, 2006). In this work, we investigate the role of other CHS including BcCHS4, BcCHS6 and BcCHS7 during the life cycle of B. cinerea. Single deletions of corresponding genes were carried out. Phenotypic analysis indicates that: (i) BcCHS4 enzyme is not essential for development and pathogenicity of the fungus; (ii) BcCHS7 is required for pathogenicity in a host dependant manner. For Bcchs6 gene disruption, we obtained only heterokaryotic strains. Indeed, sexual or asexual purification assays were unsuccessful. We concluded that class VI chitin synthase could be essential for B. cinerea and therefore BcCHS6 represents a valuable antifungal target.


Subject(s)
Botrytis/enzymology , Chitin Synthase/genetics , Fungal Proteins/genetics , Hyphae , Botrytis/genetics , Botrytis/pathogenicity , Cell Wall/genetics , Chitin/genetics , Hyphae/enzymology , Hyphae/growth & development , Plant Diseases , Virulence/genetics
18.
Antimicrob Agents Chemother ; 53(7): 2982-90, 2009 Jul.
Article in English | MEDLINE | ID: mdl-19414575

ABSTRACT

The aim of this work was to elucidate the molecular mechanisms of flucytosine (5FC) resistance and 5FC/fluconazole (FLC) cross-resistance in 11 genetically and epidemiologically unrelated clinical isolates of Candida lusitaniae. We first showed that the levels of transcription of the FCY2 gene encoding purine-cytosine permease (PCP) in the isolates were similar to that in the wild-type strain, 6936. Nucleotide sequencing of the FCY2 alleles revealed that 5FC and 5FC/FLC resistance could be correlated with a cytosine-to-thymine substitution at nucleotide 505 in the fcy2 genes of seven clinical isolates, resulting in a nonsense mutation and in a putative nonfunctional truncated PCP of 168 amino acids. Reintroducing a FCY2 wild-type allele at the fcy2 locus of a ura3 auxotrophic strain derived from the clinical isolate CL38 fcy2(C505T) restored levels of susceptibility to antifungals comparable to those of the wild-type strains. In the remaining four isolates, a polymorphic nucleotide was found in FCY1 where the nucleotide substitution T26C resulted in the amino acid replacement M9T in cytosine deaminase. Introducing this mutated allele into a 5FC- and 5FC/FLC-resistant fcy1Delta strain failed to restore antifungal susceptibility, while susceptibility was obtained by introducing a wild-type FCY1 allele. We thus found a correlation between the fcy1 T26C mutation and both 5FC and 5FC/FLC resistances. We demonstrated that only two genetic events occurred in 11 unrelated clinical isolates of C. lusitaniae to support 5FC and 5FC/FLC resistance: either the nonsense mutation C505T in the fcy2 gene or the missense mutation T26C in the fcy1 gene.


Subject(s)
Antifungal Agents/pharmacology , Candidiasis/microbiology , Codon, Nonsense/genetics , Fluconazole/pharmacology , Flucytosine/pharmacology , Mutation, Missense/genetics , Blotting, Northern , Blotting, Southern , Candida/drug effects , Candida/genetics , Drug Resistance, Fungal/genetics , Fungal Proteins/genetics , Fungal Proteins/physiology , Humans , Microbial Sensitivity Tests , Polymerase Chain Reaction
20.
Yeast ; 25(11): 849-59, 2008 Nov.
Article in English | MEDLINE | ID: mdl-19061190

ABSTRACT

In yeast, external signals such as high osmolarity or oxidant conditions activate the high osmolarity glycerol (HOG) mitogen-activated protein kinase (MAPK) cascade pathway, which consists of two upstream branches, i.e. Sho1p and Sln1p and common downstream elements, including the Pbs2p MAPK kinase and the Hog1p MAPK. We recently showed that the Candida lusitaniae SLN1 gene, potentially encoding a histidine kinase receptor, is crucial for oxidative stress adaptation when the fungus grows as budding yeast and during the early steps of pseudohyphal development. In the current study, we characterized the SHO1 gene of this opportunistic fungus. Complete loss of SHO1 function causes profound defects in pseudohyphal differentiation, especially in high osmolarity and oxidative stress conditions, suggesting a crucial role of SHO1 in the pseudohyphae morphogenetic transitions. Moreover, when grown as budding yeast, the sho1Delta mutant revealed a sensitivity to compounds that interfere with the cell wall assembly, pointing to a potential role of Sho1p in cell wall biogenesis. However, the sho1Delta mutant does not display evident cell-wall architecture modifications, such as aggregation phenotypes. Although not hypersusceptible to antifungals of clinical relevance, the sho1Delta mutants are susceptible to the filamentous fungi-specific antifungals dicarboximides and phenylpyrroles. Finally, our findings highlight some significant phenotypic differences when the C. lusitaniae sho1Delta mutant is compared with the corresponding mutants described in Saccharomyces cerevisiae, Candida albicans and Aspergillus fumigatus.


Subject(s)
Candida/physiology , Fungal Proteins/physiology , Membrane Proteins/physiology , Signal Transduction , Antifungal Agents/pharmacology , Aspergillus fumigatus/genetics , Candida/genetics , Candida/growth & development , Candida albicans/genetics , Cell Wall/metabolism , Fungal Proteins/genetics , Gene Deletion , Hyphae/growth & development , Membrane Proteins/genetics , Molecular Sequence Data , Morphogenesis , Osmotic Pressure , Oxidative Stress , Saccharomyces cerevisiae/genetics , Sequence Analysis, DNA
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