scholarly journals Effect of Osmotic Stress on the Growth, Development and Pathogenicity of Setosphaeria turcica

2021 ◽  
Vol 12 ◽  
Author(s):  
Yuwei Liu ◽  
Xiaodong Gong ◽  
Moxiao Li ◽  
Helong Si ◽  
Qihui Zhou ◽  
...  
Keyword(s):  
Osmotic Stress ◽  
Mapk Pathway ◽  
Pathogenic Fungus ◽  
Germination Rate ◽  
Phytopathogenic Fungi ◽  
Severe Condition ◽  
Potato Dextrose Agar Medium ◽  
Knock Out ◽  
Setosphaeria Turcica ◽  
Growth Development

Osmotic stress is a severe condition frequently encountered by microorganisms; however, there is limited knowledge on the influence of hyperosmotic stress on the growth, development and pathogenicity of phytopathogenic fungi. Here, three osmotic conditions (0.4 M NaCl, 0.4 M KCl, and 0.6 M sorbitol supplemented in potato dextrose agar medium) were used to identify the effect of osmotic stress on the growth, development and pathogenicity of Setosphaeria turcica which is a plant pathogenic fungus and causes northern corn leaf blight disease in maize, sorghum, and related grasses. In osmotic stress, the growth rate of mycelium was decreased, and the number of vesicular structures and flocculent secretion outside the hypha cell wall were significantly increased. The qRT-PCR results showed that the osmotic stress quickly activated the HOG-MAPK pathway, up-regulated the expression of the downstream genes, and these genes were most highly expressed within 30 min of exposure to osmotic stress. Furthermore, the germination rate and the yield of conidia were significantly higher under osmotic stress than in the control. A pathogenicity analysis confirmed that pathogenicity of the conidia which were cultured under osmotic stress was significantly enhanced. By analyzing the knock-out mutants of an osmotic stress responsed gene StFPS1, an aquaglyceroporin downstream of the HOG-MAPK pathway, we found that StFPS1 was involved in the formation of appressorium and penetration peg, which affected the penetration ability of S. turcica. In summary, our work explained the correlation between osmotic stress and growth, development, and pathogenicity in S. turcica.

scholarly journals Characterization of the mbsA Gene Encoding a Putative APSES Transcription Factor in Aspergillus fumigatus

2021 ◽  
Vol 22 (7) ◽  
pp. 3777
Author(s):  
Yong-Ho Choi ◽  
Sang-Cheol Jun ◽  
Min-Woo Lee ◽  
Jae-Hyuk Yu ◽  
Kwang-Soo Shin
Keyword(s):  
Aspergillus Fumigatus ◽  
Pathogenic Fungus ◽  
Hyphal Growth ◽  
Spore Wall ◽  
Mrna Levels ◽  
Chitin Synthesis ◽  
Helix Loop Helix ◽  
Growth Development ◽  
Opportunistic Pathogenic

The APSES family proteins are transcription factors (TFs) with a basic helix-loop-helix domain, known to regulate growth, development, secondary metabolism, and other biological processes in Aspergillus species. In the genome of the human opportunistic pathogenic fungus Aspergillus fumigatus, five genes predicted to encode APSES TFs are present. Here, we report the characterization of one of these genes, called mbsA (Afu7g05620). The deletion (Δ) of mbsA resulted in significantly decreased hyphal growth and asexual sporulation (conidiation), and lowered mRNA levels of the key conidiation genes abaA, brlA, and wetA. Moreover, ΔmbsA resulted in reduced spore germination rates, elevated sensitivity toward Nikkomycin Z, and significantly lowered transcripts levels of genes associated with chitin synthesis. The mbsA deletion also resulted in significantly reduced levels of proteins and transcripts of genes associated with the SakA MAP kinase pathway. Importantly, the cell wall hydrophobicity and architecture of the ΔmbsA asexual spores (conidia) were altered, notably lacking the rodlet layer on the surface of the ΔmbsA conidium. Comparative transcriptomic analyses revealed that the ΔmbsA mutant showed higher mRNA levels of gliotoxin (GT) biosynthetic genes, which was corroborated by elevated levels of GT production in the mutant. While the ΔmbsA mutant produced higher amount of GT, ΔmbsA strains showed reduced virulence in the murine model, likely due to the defective spore integrity. In summary, the putative APSES TF MbsA plays a multiple role in governing growth, development, spore wall architecture, GT production, and virulence, which may be associated with the attenuated SakA signaling pathway.

Abstract 375: Mechanotransduction via Titin’s N2B Element Contributes to Cardiac Remodeling

2015 ◽  
Vol 117 (suppl_1) ◽  
Author(s):  
Mathew Bull ◽  
Pooja Nair ◽  
Joshua Strom ◽  
Michael Gotthardt ◽  
Henk Granzier
Keyword(s):  
Heart Failure ◽  
Cardiac Remodeling ◽  
Mapk Pathway ◽  
Hot Spot ◽  
Pressure Overload ◽  
Volume Overload ◽  
Mitogen Activated Protein Kinase ◽  
Stress And Strain ◽  
Knock Out ◽  
Voluntary Running

Pathological remodeling is responsible for the functional deficits characteristic of heart failure patients. Understanding mechanotransduction is limited, but holds potential to provide novel therapeutic targets to treat patients with heart failure, especially those with diastolic dysfunction and preserved ejection fraction (HFpEF). Titin is the largest known protein and is abundant in muscle. It is the main contributor of passive stiffness in the heart and functions as a molecular mechano-sensor for stress and strain in the myocyte. Titin is composed of four distinct regions, (N-terminal Z-line, I-band, A-band, and C-terminal M-line), and acts as a molecular spring that is responsible for the assembly and maintenance of ultrastructure in the sarcomere. The elastic N2B element found in titin’s I-band region has been proposed as a mechano-sensor and signaling “hot spot” in the sarcomere. This study investigates the role of titin’s cardiac specific N2B element as sensor for stress and strain induced remodeling in the heart. The previously published N2B knock out (KO) mouse was subjected to a variety of stressors including transverse aortic constriction (TAC), aorto-caval fistula (ACF), chronic swimming, voluntary running and isoproterenol injections. Through chronic pathologic stress, pressure overload (TAC) and chronic volume overload (ACF), we found that the N2B element is necessary for the response to volume overload but not pressure overload as determined by changes in cardiac remodeling. Furthermore, the response to exercise either by chronic swimming or voluntary running was reduced in the N2B KO mouse. Finally, unlike the wild-type (WT) mouse, the N2B KO mouse did not respond to isoproterenol injections with hypertrophic remodeling. Ongoing work to elucidate the molecular pathways involving the N2B element and response to stress, is focused on its binding protein Four-and-a-half-LIM domains 2 (FHL2) and the mitogen activated protein kinase (MAPK) pathway. Taken together our data suggest that the N2B element contributes significantly to mechanotransduction in the heart.

scholarly journals The Putative APSES Transcription Factor RgdA Governs Growth, Development, Toxigenesis, and Virulence in Aspergillus fumigatus

mSphere ◽  
2020 ◽  
Vol 5 (6) ◽  
Author(s):  
Sang-Cheol Jun ◽  
Yong-Ho Choi ◽  
Min-Woo Lee ◽  
Jae-Hyuk Yu ◽  
Kwang-Soo Shin
Keyword(s):  
Transcription Factor ◽  
Aspergillus Fumigatus ◽  
Molecular Mechanisms ◽  
Pathogenic Fungus ◽  
Mrna Levels ◽  
Transcript Levels ◽  
Content Type ◽  
Asexual Sporulation ◽  
Human Pathogenic Fungus ◽  
Growth Development

ABSTRACT The APSES transcription factor (TF) in Aspergillus species is known to govern diverse cellular processes, including growth, development, and secondary metabolism. Here, we investigated functions of the rgdA gene (Afu3g13920) encoding a putative APSES TF in the opportunistic human-pathogenic fungus Aspergillus fumigatus. The rgdA deletion resulted in significantly decreased hyphal growth and asexual sporulation. Consistently, transcript levels of the key asexual developmental regulators abaA, brlA, and wetA were decreased in the ΔrgdA mutant compared to those in the wild type (WT). Moreover, ΔrgdA resulted in reduced spore germination rates and elevated transcript levels of genes associated with conidium dormancy. The conidial cell wall hydrophobicity and architecture were changed, and levels of the RodA protein were decreased in the ΔrgdA mutant. Comparative transcriptomic analyses revealed that the ΔrgdA mutant showed higher mRNA levels of gliotoxin (GT)-biosynthetic genes and GT production. While the ΔrgdA mutant exhibited elevated production of GT, ΔrgdA strains showed reduced virulence in the mouse model. In addition, mRNA levels of genes associated with the cyclic AMP (cAMP)-protein kinase A (PKA) signaling pathway and the SakA mitogen-activated protein (MAP) kinase pathway were increased in the ΔrgdA mutant. In summary, RgdA plays multiple roles in governing growth, development, GT production, and virulence which may involve attenuation of PKA and SakA signaling. IMPORTANCE Immunocompromised patients are susceptible to infections with the opportunistic human-pathogenic fungus Aspergillus fumigatus. This fungus causes systemic infections such as invasive aspergillosis (IA), which is one of the most life-threatening fungal diseases. To control this serious disease, it is critical to identify new antifungal drug targets. In fungi, the transcriptional regulatory proteins of the APSES family play crucial roles in controlling various biological processes, including mating, asexual sporulation and dimorphic growth, and virulence traits. This study found that a putative APSES transcription factor, RgdA, regulates normal growth, asexual development, conidium germination, spore wall architecture and hydrophobicity, toxin production, and virulence in A. fumigatus. Better understanding the molecular mechanisms of RgdA in human-pathogenic fungi may reveal a novel antifungal target for future drug development.

Mating-type genes control sexual reproduction, conidial germination and virulence in Cochliobolus lunatus

2021 ◽  
Author(s):  
Kexin Liu ◽  
Jiaqi Jia ◽  
Nan Chen ◽  
Dandan Fu ◽  
Jiaying Sun ◽  
...  
Keyword(s):  
Mating Type ◽  
Pathogenic Fungus ◽  
Germination Rate ◽  
Dry Weight ◽  
Single Copy ◽  
Conidial Germination ◽  
Curvularia Lunata ◽  
Wild Type ◽  
Cochliobolus Lunatus ◽  
Mat Genes

Cochliobolus lunatus (anamorph: Curvularia lunata) is a major pathogenic fungus that causes the Curvularia leaf spot of maize. ClMAT1-1-1 and ClMAT1-2-1, the C. lunatus orthologs of Cochliobolus heterostrophus ChMAT1-1-1 and ChMAT1-2-1, were investigated in the present study to uncover their functions in C. lunatus. Southern blot analysis showed that these mating-type MAT genes exist in the C. lunatus genome as a single copy. ClMAT1-1-1 and ClMAT1-2-1 were knocked out and complemented to generate ΔClmat1-1-1 and ΔClmat1-2-1, ΔClmat1-1-1-C and ΔClmat1-2-1-C, respectively. The mutant strains had defective sexual development and failed to produce pseudothecia. There were no significant differences in growth rate or conidia production between the mutant and wild-type strains. However, the aerial mycelia and mycelial dry weight of ΔClmat1-1-1 and ΔClmat1-2-1 were lower than that of wild type, suggesting that MAT genes affect asexual development. ClMAT genes were involved in the responses to cell wall integrity and osmotic adaptation. ΔClmat1-2-1 had a lower conidial germination rate than the wild-type strain CX-3. The virulence of ΔClmat1-2-1 and ΔClmat1-1-1 was also reduced compared to the wild type. Complementary strains could restore all the phenotypes.

The phytopathogenic fungi Leptosphaeria maculans and Leptosphaeria biglobosa: chemotaxonomical characterization of isolates and metabolite production in different culture media

2007 ◽  
Vol 53 (3) ◽  
pp. 364-371 ◽  
Author(s):  
M.  Soledade C. Pedras ◽  
Paulos B. Chumala ◽  
Yang Yu
Keyword(s):  
Culture Media ◽  
Pathogenic Fungus ◽  
Leptosphaeria Maculans ◽  
Defined Medium ◽  
Phytopathogenic Fungi ◽  
Potato Dextrose Broth ◽  
Chemical Structures ◽  
Morphologic Characteristics ◽  
Metabolite Profiles ◽  
Leptosphaeria Biglobosa

Previous molecular chemotaxonomic analyses of isolates of the plant pathogenic fungus Leptosphaeria maculans (Desm.) Ces. et de Not. (asexual stage Phoma lingam (Tode ex Fr.) Desm.) in a chemically defined medium suggested that this species complex was composed of at least three distinct groups. Subsequently, a group within L. maculans was classified as Leptosphaeria biglobosa , on the basis of morphologic characteristics and the lack of sexual crossing. To obtain clarification regarding the metabolite profiles of the various groups or species of blackleg fungi, the objectives of this work were (i) to determine the chemical structures of metabolites produced by Canadian V isolates and Polish-type isolates in potato dextrose broth (PDB) and (ii) to determine the chemotaxonomic relationship among French isolates of L. biglobosa and among Canadian W isolates and Thlaspi isolates of L. maculans. Here, we report for the first time that Canadian V isolates grown in PDB produced 2,4-dihydroxy-3,6-dimethylbenzaldehyde, a metabolite never reported from L. maculans, but none of the usual phytotoxins (sirodesmins). In addition, we report a new metabolite, 2-[2-(5-hydroxybenzofuranyl)]-3-(4-hydroxyphenyl)propanenitrile, from Polish-type isolates of L. maculans grown in PDB and the metabolite profiles of 16 Thlaspi isolates. The metabolite profiles of Thlaspi isolates indicate that these are part of two distinct groups, the Polish W group and the Canadian W group, i.e., L. biglobosa. Finally, we demonstrate that the metabolite profiles of the French isolates classified as L. biglobosa are similar to those of Canadian W isolates.

scholarly journals TBL1XR1 Ensures Balanced Neural Development Through NCOR Complex-Mediated Regulation of the MAPK Pathway

2021 ◽  
Vol 9 ◽  
Author(s):  
Giuseppina Mastrototaro ◽  
Mattia Zaghi ◽  
Luca Massimino ◽  
Matteo Moneta ◽  
Neda Mohammadi ◽  
...  
Keyword(s):  
Neural Development ◽  
Developmental Disorders ◽  
Mapk Pathway ◽  
Point Mutations ◽  
Knock Out ◽  
Human Disorders ◽  
Mecp2 Protein ◽  
Cellular Pathways ◽  
Knock Out Mice ◽  
Transcriptional Output

TBL1XR1 gene is associated with multiple developmental disorders presenting several neurological aspects. The relative protein is involved in the modulation of important cellular pathways and master regulators of transcriptional output, including nuclear receptor repressors, Wnt signaling, and MECP2 protein. However, TBL1XR1 mutations (including complete loss of its functions) have not been experimentally studied in a neurological context, leaving a knowledge gap in the mechanisms at the basis of the diseases. Here, we show that Tbl1xr1 knock-out mice exhibit behavioral and neuronal abnormalities. Either the absence of TBL1XR1 or its point mutations interfering with stability/regulation of NCOR complex induced decreased proliferation and increased differentiation in neural progenitors. We suggest that this developmental unbalance is due to a failure in the regulation of the MAPK cascade. Taken together, our results broaden the molecular and functional aftermath of TBL1XR1 deficiency associated with human disorders.

EFFECT OF THE ROOTS EXTRACT FROM Heliopsis longipes ON Aspergillus parasiticus GROWTH

Biotecnia ◽  
2018 ◽  
Vol 20 (3) ◽  
pp. 127-134 ◽  
Author(s):  
John M. Velez-Haro ◽  
Nydia E. Buitimea-Cantúa ◽  
Ema C. Rosas-Burgos ◽  
Jorge Molina-Torres ◽  
Génesis V. Buitimea-Cantúa
Keyword(s):  
Radial Growth ◽  
Inhibitory Concentration ◽  
Aspergillus Parasiticus ◽  
Pathogenic Fungus ◽  
Germination Rate ◽  
Ethanolic Extract ◽  
Pharmacological Activities ◽  
Fresh Tissue ◽  
Antifungal Effect ◽  
Organic Extracts

The organic extracts from Heliopsis longipes roots possess interesting biological and pharmacological activities. However, the effect on Aspergillus parasiticus has not been investigated so far. This study was aimed to evaluate the antifungal effect of the ethanolic extract from H. longipes roots against A. parasiticus growth. Four extract concentrations, 50, 75, 150 and 200 μg/mL were evaluated for antifungal effect, and the anti-aflatoxigenic assay was tested at 150 and 200 μg/mL. The minimal inhibitory concentration that inhibited 50 and 99% of growth (MIC50 and MIC99) were determined. Ethanolic extract was characterized by GC-EIMS analysis and its main bioactive compounds were identified. All tested concentrations inhibit the radial growth of A. parasiticus and the MIC50 and MIC99 were 116.94 and 1593.98 μg/mL, respectively. These results showed the first evidence of the antifungal effect of H. longipes on the radial growth and spore germination rate of this pathogenic fungus. The antifungal activity of H. longipes extract was attributed to affinin (7.24 ± 0.13 mg/g of fresh tissue), the most abundant alkamide detected by GC-EIMS analysis. Although, the extract did not inhibit the aflatoxins´ production, it can be used to prevent A. parasiticus growth before the mycotoxins production occur. Therefore, the extract has potential as natural antifungal agent against A. parasiticus contamination.

scholarly journals Monitoring the volatile language of fungi using gas chromatography-ion mobility spectrometry

2021 ◽  
Vol 413 (11) ◽  
pp. 3055-3067
Author(s):  
Verena Speckbacher ◽  
Susanne Zeilinger ◽  
Stefan Zimmermann ◽  
Christopher A. Mayhew ◽  
Helmut Wiesenhofer ◽  
...  
Keyword(s):  
Gas Chromatography ◽  
Real Time ◽  
Ion Mobility ◽  
Pathogenic Fungus ◽  
Control Agent ◽  
Fungal Species ◽  
Phytopathogenic Fungi ◽  
Biological Pest Control ◽  
Microbial Volatile Organic Compounds ◽  
On Line

AbstractFusarium oxysporum is a plant pathogenic fungus leading to severe crop losses in agriculture every year. A sustainable way of combating this pathogen is the application of mycoparasites—fungi parasitizing other fungi. The filamentous fungus Trichoderma atroviride is such a mycoparasite that is able to antagonize phytopathogenic fungi. It is therefore frequently applied as a biological pest control agent in agriculture. Given that volatile metabolites play a crucial role in organismic interactions, the major aim of this study was to establish a method for on-line analysis of headspace microbial volatile organic compounds (MVOCs) during cultivation of different fungi. An ion mobility spectrometer with gas chromatographic pre-separation (GC-IMS) enables almost real-time information of volatile emissions with good selectivity. Here we illustrate the successful use of GC-IMS for monitoring the time- and light-dependent release of MVOCs by F. oxysporum and T. atroviride during axenic and co-cultivation. More than 50 spectral peaks were detected, which could be assigned to 14 volatile compounds with the help of parallel gas chromatography-mass spectrometric (GC-MS) measurements. The majority of identified compounds are alcohols, such as ethanol, 1-propanol, 2-methyl propanol, 2-methyl butanol, 3-methyl-1-butanol and 1-octen-3-ol. In addition to four ketones, namely acetone, 2-pentanone, 2-heptanone, 3-octanone, and 2-octanone; two esters, ethyl acetate and 1-butanol-3-methylacetate; and one aldehyde, 3-methyl butanal, showed characteristic profiles during cultivation depending on axenic or co-cultivation, exposure to light, and fungal species. Interestingly, 2-octanone was produced only in co-cultures of F. oxysporum and T. atroviride, but it was not detected in the headspace of their axenic cultures. The concentrations of the measured volatiles were predominantly in the low ppbv range; however, values above 100 ppbv were detected for several alcohols, including ethanol, 2-methylpropanol, 2-methyl butanol, 1- and 3-methyl butanol, and for the ketone 2-heptanone, depending on the cultivation conditions. Our results highlight that GC-IMS analysis can be used as a valuable analytical tool for identifying specific metabolite patterns for chemotaxonomic and metabolomic applications in near-to-real time and hence easily monitor temporal changes in volatile concentrations that take place in minutes.

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