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

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.

scholarly journals The Sclerotinia sclerotiorum Slt2 mitogen-activated protein kinase ortholog, SMK3, is required for infection initiation but not lesion expansion

2016 ◽  
Vol 62 (10) ◽  
pp. 836-850 ◽  
Author(s):  
Zafer Dallal Bashi ◽  
Sanjaya Gyawali ◽  
Diana Bekkaoui ◽  
Cathy Coutu ◽  
Leora Lee ◽  
...  
Keyword(s):  
Cell Wall ◽  
Sclerotinia Sclerotiorum ◽  
Elevated Temperatures ◽  
Fungal Growth ◽  
Cell Wall Integrity ◽  
Mitogen Activated Protein Kinase ◽  
Phytopathogenic Fungus ◽  
Growth Physiology ◽  
Solid Media ◽  
Mitogen Activated Protein

Mitogen-activated protein kinases (MAPKs) play a central role in transferring signals and regulating gene expression in response to extracellular stimuli. An ortholog of the Saccharomyces cerevisiae cell wall integrity MAPK was identified in the phytopathogenic fungus Sclerotinia sclerotiorum. Disruption of the S. sclerotiorum Smk3 gene severely reduced virulence on intact host plant leaves but not on leaves stripped of cuticle wax. This was attributed to alterations in hyphal apical dominance leading to the inability to aggregate and form infection cushions. The mutation also caused loss of the ability to produce sclerotia, increased aerial hyphae formation, and altered hyphal hydrophobicity and cell wall integrity. Mutants had slower radial expansion rates on solid media but more tolerance to elevated temperatures. Loss of the SMK3 cell wall integrity MAPK appears to have impaired the ability of S. sclerotiorum to sense its surrounding environment, leading to misregulation of a variety of functions. Many of the phenotypes were similar to those observed in S. sclerotiorum adenylate cyclase and SMK1 MAPK mutants, suggesting that these signaling pathways co-regulate aspects of fungal growth, physiology, and pathogenicity.

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 The Aspergillus fumigatus Mucin MsbA Regulates the Cell Wall Integrity Pathway and Controls Recognition of the Fungus by the Immune System

mSphere ◽  
2019 ◽  
Vol 4 (3) ◽  
Author(s):  
Isabella Luísa da Silva Gurgel ◽  
Karina Talita de Oliveira Santana Jorge ◽  
Nathália Luísa Sousa de Oliveira Malacco ◽  
Jéssica Amanda Marques Souza ◽  
Marina Campos Rocha ◽  
...  
Keyword(s):  
Cell Wall ◽  
Immune System ◽  
Aspergillus Fumigatus ◽  
Fungal Growth ◽  
Cell Wall Composition ◽  
Cell Wall Integrity ◽  
Cell Physiology ◽  
Content Type ◽  
Cell Wall Morphogenesis

ABSTRACT Aspergillus fumigatus is a filamentous fungus which causes invasive pulmonary aspergillosis in immunocompromised individuals. In fungi, cell signaling and cell wall plasticity are crucial for maintaining physiologic processes. In this context, Msb2 is an important signaling mucin responsible for activation of a variety of mitogen-activated protein kinase (MAPK)-dependent signaling pathways that regulate cell growth in several organisms, such as the cell wall integrity (CWI) pathway. Here, we aimed to characterize the MSB2 homologue in A. fumigatus. Our results showed that MsbA plays a role in the vegetative and reproductive development of the fungus, in stress adaptation, and in resistance to antifungal drugs by modulating the CWI pathway gene expression. Importantly, cell wall composition is also responsible for activation of diverse receptors of the host immune system, thus leading to a proper immune response. In a model of acute Aspergillus pulmonary infection, results demonstrate that the ΔmsbA mutant strain induced less inflammation with diminished cell influx into the lungs and lower cytokine production, culminating in increased lethality rate. These results characterize for the first time the role of the signaling mucin MsbA in the pathogen A. fumigatus, as a core sensor for cell wall morphogenesis and an important regulator of virulence. IMPORTANCE Aspergillus fumigatus is an opportunistic fungus with great medical importance. During infection, Aspergillus grows, forming hyphae that colonize the lung tissue and invade and spread over the mammal host, resulting in high mortality rates. The knowledge of the mechanisms responsible for regulation of fungal growth and virulence comprises an important point to better understand fungal physiology and host-pathogen interactions. Msb2 is a mucin that acts as a sensor and an upstream regulator of the MAPK pathway responsible for fungal development in Candida albicans and Aspergillus nidulans. Here, we show the role of the signaling mucin MsbA in the pathogen A. fumigatus, as a core sensor for cell wall morphogenesis, fungal growth, and virulence. Moreover, we show that cell wall composition, controlled by MsbA, is detrimental for fungal recognition and clearance by immune cells. Our findings are important for the understanding of how fungal sensors modulate cell physiology.

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