MaFKS, a β-1,3-glucan synthase, is involved in cell wall integrity, hyperosmotic pressure tolerance and conidiation in Metarhizium acridum

2011 ◽  
Vol 57 (4) ◽  
pp. 253-260 ◽  
Author(s):  
Min Yang ◽  
Kai Jin ◽  
Yuxian Xia
Keyword(s):  
Cell Wall ◽  
Cell Wall Integrity ◽  
Metarhizium Acridum ◽  
Glucan Synthase ◽  
Pressure Tolerance

scholarly journals MaAreB, a GATA Transcription Factor, Is Involved in Nitrogen Source Utilization, Stress Tolerances and Virulence in Metarhizium acridum

2021 ◽  
Vol 7 (7) ◽  
pp. 512
Author(s):  
Chaochuang Li ◽  
Qipei Zhang ◽  
Yuxian Xia ◽  
Kai Jin
Keyword(s):  
Cell Wall ◽  
Transcription Factor ◽  
Functional Characterization ◽  
Turgor Pressure ◽  
Nitrogen Utilization ◽  
Cell Wall Integrity ◽  
Homologous Proteins ◽  
Calcofluor White ◽  
Metarhizium Acridum ◽  
Gata Transcription Factor

The nitrogen catabolite repression (NCR) pathway is involved in nitrogen utilization, in which the global GATA transcription factor AreA plays an indispensable role and has been reported in many fungi. However, relatively few studies are focused on AreB, another GATA transcription factor in the NCR pathway and the functions of AreB are largely unknown in entomopathogenic fungi. Here, we characterized MaAreB in the model entomopathogenic fungus Metarhizium acridum. Sequence arrangement found that MaAreB had a conserved GATA zinc finger DNA binding domain and a leucine zipper domain. Disruption of MaAreB affected the nitrogen utilization and led to decelerated conidial germination and hyphal growth, decreased conidial yield, and lower tolerances to UV-B irradiation and heat-shock. Furthermore, the MaAreB mutant (ΔMaAreB) exhibited increased sensitivity to CFW (Calcofluor white), decreased cell wall contents (chitin and β-1,3-glucan) and reduced expression levels of some genes related to cell wall integrity, indicating that disruption of MaAreB affected the cell wall integrity. Bioassays showed that the virulence of the ΔMaAreB strain was decreased in topical inoculation but not in intra-hemocoel injection. Consistently, deletion of MaAreB severely impaired the appressorium formation and reduced the turgor pressure of appressorium. These results revealed that MaAreB regulated fungal nitrogen utilization, cell wall integrity and biological control potential, which would contribute to the functional characterization of AreB homologous proteins in other insect fungal pathogens, and even filamentous fungi.

MaPmt4, a protein O-mannosyltransferase, contributes to cell wall integrity, stress tolerance and virulence in Metarhizium acridum

2019 ◽  
Vol 65 (4) ◽  
pp. 1025-1040 ◽  
Author(s):  
Tingting Zhao ◽  
Huiting Tian ◽  
Yuxian Xia ◽  
Kai Jin
Keyword(s):  
Cell Wall ◽  
Stress Tolerance ◽  
Cell Wall Integrity ◽  
Metarhizium Acridum

scholarly journals MpkA-Dependent and -Independent Cell Wall Integrity Signaling in Aspergillus nidulans

2007 ◽  
Vol 6 (8) ◽  
pp. 1497-1510 ◽  
Author(s):  
Tomonori Fujioka ◽  
Osamu Mizutani ◽  
Kentaro Furukawa ◽  
Natsuko Sato ◽  
Akira Yoshimi ◽  
...  
Keyword(s):  
Cell Wall ◽  
Transcriptional Regulation ◽  
Aspergillus Nidulans ◽  
Cell Wall Integrity ◽  
Mitogen Activated Protein Kinase ◽  
Dependent Manner ◽  
Wild Type ◽  
Glucan Synthase ◽  
Cell Wall Biogenesis ◽  
In The Wild

ABSTRACT Cell wall integrity signaling (CWIS) maintains cell wall biogenesis in fungi, but only a few transcription factors (TFs) and target genes downstream of the CWIS cascade in filamentous fungi are known. Because a mitogen-activated protein kinase (MpkA) is a key CWIS enzyme, the transcriptional regulation of mpkA and of cell wall-related genes (CWGs) is important in cell wall biogenesis. We cloned Aspergillus nidulans mpkA; rlmA, a TF gene orthologous to Saccharomyces cerevisiae RLM1 that encodes Rlm1p, a major Mpk1p-dependent TF that regulates the transcription of MPK1 besides that of CWGs; and Answi4 and Answi6, homologous to S. cerevisiae SWI4 and SWI6, encoding the Mpk1p-activating TF complex Swi4p-Swi6p, which regulates CWG transcription in a cell cycle-dependent manner. A. nidulans rlmA and mpkA cDNA functionally complemented S. cerevisiae rlm1Δ and mpk1Δ mutants, respectively, but Answi4 and Answi6 cDNA did not complement swi4Δ and swi6Δ mutants. We constructed A. nidulans rlmA, Answi4 and Answi6, and mpkA disruptants (rlmAΔ, Answi4Δ Answi6Δ, and mpkAΔ strains) and analyzed mpkA and CWG transcripts after treatment with a β-1,3-glucan synthase inhibitor (micafungin) that could activate MpkA via CWIS. Levels of mpkA transcripts in the mutants as well as those in the wild type were changed after micafungin treatment. The β-glucuronidase reporter gene controlled by the mpkA promoter was expressed in the wild type but not in the mpkAΔ strain. Thus, mpkA transcription seems to be autoregulated by CWIS via MpkA but not by RlmA or AnSwi4-AnSwi6. The transcription of most CWGs except α-1,3-glucan synthase genes (agsA and agsB) was independent of RlmA and AnSwi4-AnSwi6 and seemed to be regulated by non-MpkA signaling. The transcriptional regulation of mpkA and of CWGs via CWIS in A. nidulans differs significantly from that in S. cerevisiae.

scholarly journals Novel Rho GTPase Involved in Cytokinesis and Cell Wall Integrity in the Fission Yeast Schizosaccharomyces pombe

2003 ◽  
Vol 2 (3) ◽  
pp. 521-533 ◽  
Author(s):  
Beatriz Santos ◽  
Javier Gutiérrez ◽  
Teresa M. Calonge ◽  
Pilar Pérez
Keyword(s):  
Cell Wall ◽  
Schizosaccharomyces Pombe ◽  
Fission Yeast ◽  
Rho Gtpases ◽  
Rho Gtpase ◽  
Cell Wall Integrity ◽  
Glucan Synthase ◽  
Actin Organization ◽  
Morphological Defects

ABSTRACT The Rho family of GTPases is present in all eukaryotic cells from yeast to mammals; they are regulators in signaling pathways that control actin organization and morphogenetic processes. In yeast, Rho GTPases are implicated in cell polarity processes and cell wall biosynthesis. It is known that Rho1 and Rho2 are key proteins in the construction of the cell wall, an essential structure that in Schizosaccharomyces pombe is composed of β-glucan, α-glucan, and mannoproteins. Rho1 regulates the synthesis of 1,3-β-d-glucan by activation of the 1,3-β-d-glucan synthase, and Rho2 regulates the synthesis of α-glucan by the 1,3-α-d-glucan synthase Mok1. Here we describe the characterization of another Rho GTPase in fission yeast, Rho4. rho4Δ cells are viable but display cell separation defects at high temperature. In agreement with this observation, Rho4 localizes to the septum. Overexpression of rho4 + causes lysis and morphological defects. Several lines of evidence indicate that both rho4 + deletion or rho4 + overexpression result in a defective cell wall, suggesting an additional role for Rho4 in cell wall integrity. rho4Δ cells also accumulate secretory vesicles around the septum and are defective in actin polarization. We propose that Rho4 could be involved in the regulation of the septum degradation during cytokinesis.

scholarly journals Members of chitin synthase family in Metarhizium acridum differentially affect fungal growth, stress tolerances, cell wall integrity and virulence

2019 ◽  
Vol 15 (8) ◽  
pp. e1007964 ◽  
Author(s):  
Junjie Zhang ◽  
Hui Jiang ◽  
Yanru Du ◽  
Nemat O. Keyhani ◽  
Yuxian Xia ◽  
...  
Keyword(s):  
Cell Wall ◽  
Fungal Growth ◽  
Growth Stress ◽  
Cell Wall Integrity ◽  
Chitin Synthase ◽  
Metarhizium Acridum

The Regulatory Function of the Molecular Chaperone Hsp90 in the Cell Wall Integrity of Pathogenic Fungi

2018 ◽  
Vol 16 (1) ◽  
pp. 44-53
Author(s):  
Marina Campos Rocha ◽  
Camilla Alves Santos ◽  
Iran Malavazi
Keyword(s):  
Cell Wall ◽  
Antifungal Therapy ◽  
Molecular Chaperone ◽  
Regulatory Protein ◽  
Pathogenic Fungi ◽  
Antifungal Drugs ◽  
Cell Wall Integrity ◽  
Regulatory Function ◽  
Loss Of Function ◽  
Hsp90 Inhibition

Different signaling cascades including the Cell Wall Integrity (CWI), the High Osmolarity Glycerol (HOG) and the Ca2+/calcineurin pathways control the cell wall biosynthesis and remodeling in fungi. Pathogenic fungi, such as Aspergillus fumigatus and Candida albicans, greatly rely on these signaling circuits to cope with different sources of stress, including the cell wall stress evoked by antifungal drugs and the host’s response during infection. Hsp90 has been proposed as an important regulatory protein and an attractive target for antifungal therapy since it stabilizes major effector proteins that act in the CWI, HOG and Ca2+/calcineurin pathways. Data from the human pathogen C. albicans have provided solid evidence that loss-of-function of Hsp90 impairs the evolution of resistance to azoles and echinocandin drugs. In A. fumigatus, Hsp90 is also required for cell wall integrity maintenance, reinforcing a coordinated function of the CWI pathway and this essential molecular chaperone. In this review, we focus on the current information about how Hsp90 impacts the aforementioned signaling pathways and consequently the homeostasis and maintenance of the cell wall, highlighting this cellular event as a key mechanism underlying antifungal therapy based on Hsp90 inhibition.

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