Adaptation and response to mycotoxin presence in pathogen-pathogen interactions within the Fusarium genus

2016 ◽  
Vol 9 (4) ◽  
pp. 565-575 ◽  
Author(s):  
A. Dawidziuk ◽  
G. Koczyk ◽  
D. Popiel
Keyword(s):  
Fusarium Graminearum ◽  
Plant Pathogens ◽  
Fusarium Verticillioides ◽  
Warning Signal ◽  
Resistance Mechanisms ◽  
Growth Patterns ◽  
Fungal Plant Pathogens ◽  
Low Concentrations ◽  
Dose Dependent

The ability of fungal plant pathogens to exude bioactive compounds is an important element of competition in a changing environment. The filamentous fungi usually retain a number of adaptations related not only to the production of toxic compounds by themselves but also to the mitigation of exogenous influences by toxins present in the environment. We examined a distinct effect of toxins on morphology, growth patterns and gene expression after stimulation in mycotoxin-producing and nonproducing isolates representing four evolutionarily divergent species (and chemotypes) within the Fusarium genus (Fusarium graminearum, Fusarium oxysporum, Fusarium proliferatum and Fusarium verticillioides). The aim of our work was to investigate the influence of mycotoxins present in the environment on fungal isolates belonging to evolutionarily divergent complexes within Fusarium genus. The results point to retention of resistance mechanisms in non-producer isolates (F. oxysporum) and specific dose-dependent differences in response to other mycotoxins. In particular, the growth of Fusarium graminearum (confirmed zearalenone and trichothecene producer) was shown to be significantly inhibited by fumonisin B1 and deoxynivalenol. Conversely, spread of Fusarium verticillioides was accelerated by low concentrations (0.5 mg/l) of nivalenol and zearalenone and deoxynivalenol addition resulted in upregulation of the fumonisin poliketyde synthase (FUM1). The basics of competition between divergent fusaria can be described by ‘rock-paper-scissors’ theory, but some of the effects can be explained by other interactions, e.g. autotoxicity of deoxynivalenol and the potential role of low doses of trichothecenes and zearalenone acting as a ‘warning signal’ for competing species.

Regulation and Dynamics of Gene Expression During the Life Cycle of Fusarium graminearum

2020 ◽  
Vol 110 (8) ◽  
pp. 1368-1374
Author(s):  
Elizabeth K. Brauer ◽  
Rajagopal Subramaniam ◽  
Linda J. Harris
Keyword(s):  
Gene Expression ◽  
Fusarium Graminearum ◽  
Fungal Pathogens ◽  
Plant Pathogens ◽  
Transcriptional Profiling ◽  
Fungal Plant Pathogens ◽  
Essential Components ◽  
Host Infection

Fungal pathogens survive harsh environments and overcome physical, temporal, and chemical barriers to colonize their hosts and reproduce. Fusarium graminearum was one of the first fungal plant pathogens for which transcriptomic tools were developed, making analysis of gene expression a cornerstone approach in studying its biology. The analysis of gene expression in diverse in vitro conditions and during infection of different cereal crops has revealed subsets of both unique and shared transcriptionally regulated genes. Together with genetic studies, these approaches have enhanced our understanding of the development and infection cycle of this economically important pathogen. Here, we will outline recent advances in transcriptional profiling during sporogenesis, spore germination, vegetative growth, and host infection. Several transcriptional regulators have been identified as essential components in these responses and the role of select transcription factors will be highlighted. Finally, we describe some of the gaps in our understanding of F. graminearum biology and how expression analysis could help to address these gaps.

THE EFFECT OF ANGIOTENSIN ON RAT INTESTINAL FLUID TRANSFER

1970 ◽  
Vol 48 (1) ◽  
pp. 39-NP ◽  
Author(s):  
N. T. DAVIES ◽  
K. A. MUNDAY ◽  
B. J. PARSONS
Keyword(s):  
Fluid Transport ◽  
Direct Action ◽  
Rat Jejunum ◽  
Intestinal Fluid ◽  
Low Concentrations ◽  
Fluid Transfer ◽  
High Concentrations ◽  
Dose Dependent ◽  
Everted Sacs

SUMMARY Fluid transfer by isolated everted sacs of rat jejunum, ileum and intact colon prepared from adrenalectomized-nephrectomized rats 48 h after operation was reduced when compared with that of sacs prepared from untreated controls (P < 0·001). Angiotensin at 10−10 g/ml significantly (P < 0·01) stimulated fluid transfer by intestinal sacs prepared from the adrenalectomized-nephrectomized rats; all three regions of gut were equally sensitive. Fluid transfer was similarly reduced in stripped colon sacs prepared from adrenalectomized-nephrectomized rats. Angiotensin had a dose-dependent biphasic action on fluid transfer by stripped colon sacs: low concentrations (10−11 and 10−12 g/ml) stimulated (P < 0·05), whilst high concentrations (10−9 and 10−8 g/ml) inhibited fluid transfer (P < 0·01). Histological examination of the colon preparations showed that the stripping procedure removed the ganglia, indicating that both angiotensin effects were due to direct action on the colon mucosa. The significance of these results is discussed in relation to the role of angiotensin in the control of salt and fluid transport by the mammalian kidney and other epithelial tissues.

scholarly journals Extracellular Vesicles from Fusarium graminearum Contain Protein Effectors Expressed during Infection of Corn

2021 ◽  
Vol 7 (11) ◽  
pp. 977
Author(s):  
Donovan Garcia-Ceron ◽  
Rohan G. T. Lowe ◽  
James A. McKenna ◽  
Linda M. Brain ◽  
Charlotte S. Dawson ◽  
...  
Keyword(s):  
Fusarium Graminearum ◽  
Extracellular Vesicles ◽  
Plant Pathogens ◽  
Control Mechanisms ◽  
Pathogenic Yeast ◽  
Fungal Virulence ◽  
Fungal Plant Pathogens ◽  
Low Efficiency ◽  
Plant Pathogenesis

Fusarium graminearum (Fgr) is a devastating filamentous fungal pathogen that causes diseases in cereals, while producing mycotoxins that are toxic for humans and animals, and render grains unusable. Low efficiency in managing Fgr poses a constant need for identifying novel control mechanisms. Evidence that fungal extracellular vesicles (EVs) from pathogenic yeast have a role in human disease led us to question whether this is also true for fungal plant pathogens. We separated EVs from Fgr and performed a proteomic analysis to determine if EVs carry proteins with potential roles in pathogenesis. We revealed that protein effectors, which are crucial for fungal virulence, were detected in EV preparations and some of them did not contain predicted secretion signals. Furthermore, a transcriptomic analysis of corn (Zea mays) plants infected by Fgr revealed that the genes of some of the effectors were highly expressed in vivo, suggesting that the Fgr EVs are a mechanism for the unconventional secretion of effectors and virulence factors. Our results expand the knowledge on fungal EVs in plant pathogenesis and cross-kingdom communication, and may contribute to the discovery of new antifungals.

scholarly journals Role of Lipid Composition and Lipid Peroxidation in the Sensitivity of Fungal Plant Pathogens to Aluminum Chloride and Sodium Metabisulfite

2007 ◽  
Vol 73 (9) ◽  
pp. 2820-2824 ◽  
Author(s):  
Tyler J. Avis ◽  
Mélanie Michaud ◽  
Russell J. Tweddell
Keyword(s):  
Lipid Peroxidation ◽  
Fatty Acid ◽  
Aluminum Chloride ◽  
Plant Pathogens ◽  
Membrane Lipids ◽  
Membrane Integrity ◽  
Sodium Metabisulfite ◽  
Fatty Acid Unsaturation ◽  
Fungal Plant Pathogens

ABSTRACT Aluminum chloride and sodium metabisulfite have shown high efficacy at low doses in controlling postharvest pathogens on potato tubers. Direct effects of these two salts included the loss of cell membrane integrity in exposed pathogens. In this work, four fungal potato pathogens were studied in order to elucidate the role of membrane lipids and lipid peroxidation in the relative sensitivity of microorganisms exposed to these salts. Inhibition of mycelial growth in these fungi varied considerably and revealed sensitivity groups within the tested fungi. Analysis of fatty acids in these fungi demonstrated that sensitivity was related to high intrinsic fatty acid unsaturation. When exposed to the antifungal salts, sensitive fungi demonstrated a loss of fatty acid unsaturation, which was accompanied by an elevation in malondialdehyde content (a biochemical marker of lipid peroxidation). Our data suggest that aluminum chloride and sodium metabisulfite could induce lipid peroxidation in sensitive fungi, which may promote the ensuing loss of integrity in the plasma membrane. This direct effect on fungal membranes may contribute, at least in part, to the observed antimicrobial effects of these two salts.

scholarly journals Chromatin Dynamics Contribute to the Spatiotemporal Expression Pattern of Virulence Genes in a Fungal Plant Pathogen

mBio ◽  
2020 ◽  
Vol 11 (5) ◽  
Author(s):  
Lukas Meile ◽  
Jules Peter ◽  
Guido Puccetti ◽  
Julien Alassimone ◽  
Bruce A. McDonald ◽  
...  
Keyword(s):  
Plant Pathogen ◽  
Plant Pathogens ◽  
Chromatin Modifications ◽  
Zymoseptoria Tritici ◽  
Content Type ◽  
Spatiotemporal Expression ◽  
Effector Genes ◽  
Fungal Plant Pathogens ◽  
Fungal Plant Pathogen

ABSTRACT Dynamic changes in transcription profiles are key for the success of pathogens in colonizing their hosts. In many pathogens, genes associated with virulence, such as effector genes, are located in regions of the genome that are rich in transposable elements and heterochromatin. The contribution of chromatin modifications to gene expression in pathogens remains largely unknown. Using a combination of a reporter gene-based approach and chromatin immunoprecipitation, we show that the heterochromatic environment of effector genes in the fungal plant pathogen Zymoseptoria tritici is a key regulator of their specific spatiotemporal expression patterns. Enrichment in trimethylated lysine 27 of histone H3 dictates the repression of effector genes in the absence of the host. Chromatin decondensation during host colonization, featuring a reduction in this repressive modification, indicates a major role for epigenetics in effector gene induction. Our results illustrate that chromatin modifications triggered during host colonization determine the specific expression profile of effector genes at the cellular level and, hence, provide new insights into the regulation of virulence in fungal plant pathogens. IMPORTANCE Fungal plant pathogens possess a large repertoire of genes encoding putative effectors, which are crucial for infection. Many of these genes are expressed at low levels in the absence of the host but are strongly induced at specific stages of the infection. The mechanisms underlying this transcriptional reprogramming remain largely unknown. We investigated the role of the genomic environment and associated chromatin modifications of effector genes in controlling their expression pattern in the fungal wheat pathogen Zymoseptoria tritici. Depending on their genomic location, effector genes are epigenetically repressed in the absence of the host and during the initial stages of infection. Derepression of effector genes occurs mainly during and after penetration of plant leaves and is associated with changes in histone modifications. Our work demonstrates the role of chromatin in shaping the expression of virulence components and, thereby, the interaction between fungal pathogens and their plant hosts.

Role of tight-junctional pathways in bile salt-induced increases in colonic permeability

1983 ◽  
Vol 245 (6) ◽  
pp. G816-G823 ◽  
Author(s):  
R. W. Freel ◽  
M. Hatch ◽  
D. L. Earnest ◽  
A. M. Goldner
Keyword(s):  
Bile Salt ◽  
Ussing Chamber ◽  
Intercellular Spaces ◽  
Low Concentrations ◽  
Lateral Intercellular Spaces ◽  
In Series ◽  
Junctional Complexes ◽  
Dose Dependent ◽  
Tracer Experiments

The effects of a dihydroxy bile salt, taurochenodeoxycholate (TCDC), on the permeability and conductance of isolated, short-circuited segments of the rabbit descending colon were examined using conventional Ussing chamber techniques. Increasing concentrations of TCDC (1℃4 mM) produced dose-dependent increases in sodium backflux (JNas leads to m) and tissue conductance (Gt) when applied to either the mucosal or serosal salines. However, mucosal addition was twice as potent in increasing JNas leads to m and Gt at 4 mM. Tracer experiments indicated that the transepithelial serosal-to-mucosal fluxes of sodium and mannitol are via an aqueous, unrestricted, free-solution pathway, while albumin movements are restricted through this pathway both in the absence and presence of mucosal TCDC. The changes in JNas leads to m, JMans leads to m, and Gt caused by 4 mM mucosal TCDC were largely reversed by rinsing the mucosal chamber with fresh buffer. It was also observed that osmotically induced volume flows in the serosal-to-mucosal direction could offset or reverse the changes in Gt produced by 2 mM mucosal TCDC, suggesting that the enhanced conductance pathway is in series with the lateral intercellular spaces. Taken together, these results suggest that low concentrations of TCDC alter the integrity of tight-junctional complexes between the epithelial cells of the rabbit colon.

Fungal plant pathogens and soil biodiversity

2003 ◽  
Vol 83 (Special Issue) ◽  
pp. 331-336 ◽  
Author(s):  
R. D. Reeleder
Keyword(s):  
Disease Control ◽  
Management Strategy ◽  
Fungal Pathogens ◽  
Plant Pathogens ◽  
Molecular Techniques ◽  
Control Measures ◽  
Soil Biodiversity ◽  
Naturally Occurring ◽  
Fungal Plant Pathogens

The role of biodiversity as it affects the control of soil-borne fungal pathogens is discussed. Soil-borne fungal plant pathogens have often proven difficult to manage with conventional methods of disease control. Nonetheless, researchers have characterized several naturally occurring “disease-suppressive” soils where crop loss from disease is less than would otherwise be expected. Suppressive soils can also result from the incorporation of various amendments into soil. In most cases, disease control in such soils has been shown to be biological in nature; that is, soil organisms appear to directly or indirectly inhibit the development of disease. Increased knowledge of the identity and functioning of these organisms may support the development of techniques that can be used to develop suppressiveness in soils that are otherwise disease-conducive. Populations of pathogens themselves have been shown to exhibit considerable genetic diversity; the ability of populations to respond to disease control measures should be considered when developing a management strategy. New molecular techniques can be exploited to better characterize soil communities, including the pathogens themselves, as well as community responses to various disease control options. The contributions of Canadian researchers to these areas are discussed and models for further study are proposed. Key words: Biocontrol, molecular technologies, functional diversity, integrated pest management

scholarly journals Towards the Forest Virome: High-Throughput Sequencing Drastically Expands Our Understanding on Virosphere in Temperate Forest Ecosystems

2021 ◽  
Vol 9 (8) ◽  
pp. 1730
Author(s):  
Artemis Rumbou ◽  
Eeva J. Vainio ◽  
Carmen Büttner
Keyword(s):  
Plant Pathogens ◽  
High Throughput Sequencing ◽  
Plant Protection ◽  
Forest Health ◽  
Practical Applications ◽  
Fungal Plant Pathogens ◽  
Fungal Associates ◽  
Quantitative Impact ◽  
Symbiotic Microbiota

Thanks to the development of HTS technologies, a vast amount of genetic information on the virosphere of temperate forests has been gained in the last seven years. To estimate the qualitative/quantitative impact of HTS on forest virology, we have summarized viruses affecting major tree/shrub species and their fungal associates, including fungal plant pathogens, mutualists and saprotrophs. The contribution of HTS methods is extremely significant for forest virology. Reviewed data on viral presence in holobionts allowed us a first attempt to address the role of virome in holobionts. Forest health is dependent on the variability of microorganisms interacting with the host tree/holobiont; symbiotic microbiota and pathogens engage in a permanent interplay, which influences the host. Through virus–virus interplays synergistic or antagonistic relations may evolve, which may drastically affect the health of the holobiont. Novel insights of these interplays may allow practical applications for forest plant protection based on endophytes and mycovirus biocontrol agents. The current analysis is conceived in light of the prospect that novel viruses may initiate an emergent infectious disease and that measures for the avoidance of future outbreaks in forests should be considered.

scholarly journals Steroid hormones modulate galectin-1 in the trophoblast HTR-8/SVneocell line

2008 ◽  
Vol 60 (1) ◽  
pp. 11-23 ◽  
Author(s):  
Zanka Bojic-Trbojevic ◽  
Milica Bozic ◽  
Ljiljana Vicovac
Keyword(s):  
Steroid Hormones ◽  
Cell Invasion ◽  
Regulatory Role ◽  
Dependent Manner ◽  
Data Support ◽  
Low Concentrations ◽  
Dose Dependent

The effects of steroids on galectin-1 (gal-1) were studied in HTR-8/SVneo cells by immunocytochemistry, cell-based ELISA, the MTT proliferation test and the Matrigel TM invasion test. Dexamethasone (DEX), progesterone (PRG), and mifepristone (RU486) were used. Gal-1 was modulated in a steroid- and dose-dependent manner by DEX, which mildly but significantly stimulated production at low concentrations (0.1-10 nM), and inhibited it at 100 nM, while the effects of PRG and RU486 were opposite. HTR-8/SVneo cell invasion of Matrigel was significantly decreased in the presence of DEX and lactose. The obtained data support the proposed regulatory role of steroids in trophoblast gal-1 production.

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