scholarly journals Chitin-Binding Protein of Verticillium nonalfalfae Disguises Fungus from Plant Chitinases and Suppresses Chitin-Triggered Host Immunity

2019 ◽  
Vol 32 (10) ◽  
pp. 1378-1390 ◽  
Author(s):  
Helena Volk ◽  
Kristina Marton ◽  
Marko Flajšman ◽  
Sebastjan Radišek ◽  
Hui Tian ◽  
...  
Keyword(s):  
Fungal Infections ◽  
Binding Protein ◽  
Host Immunity ◽  
Binding Motif ◽  
Carbohydrate Binding ◽  
Suspension Cells ◽  
Fungal Cell ◽  
Verticillium Nonalfalfae ◽  
Chitin Binding Protein ◽  
Plant Chitinases

During fungal infections, plant cells secrete chitinases, which digest chitin in the fungal cell walls. The recognition of released chitin oligomers via lysin motif (LysM)-containing immune host receptors results in the activation of defense signaling pathways. We report here that Verticillium nonalfalfae, a hemibiotrophic xylem-invading fungus, prevents these digestion and recognition processes by secreting a carbohydrate-binding motif 18 (CBM18)-chitin-binding protein, VnaChtBP, which is transcriptionally activated specifically during the parasitic life stages. VnaChtBP is encoded by the Vna8.213 gene, which is highly conserved within the species, suggesting high evolutionary stability and importance for the fungal lifestyle. In a pathogenicity assay, however, Vna8.213 knockout mutants exhibited wilting symptoms similar to the wild-type fungus, suggesting that Vna8.213 activity is functionally redundant during fungal infection of hop. In a binding assay, recombinant VnaChtBP bound chitin and chitin oligomers in vitro with submicromolar affinity and protected fungal hyphae from degradation by plant chitinases. Moreover, the chitin-triggered production of reactive oxygen species from hop suspension cells was abolished in the presence of VnaChtBP, indicating that VnaChtBP also acts as a suppressor of chitin-triggered immunity. Using a yeast-two-hybrid assay, circular dichroism, homology modeling, and molecular docking, we demonstrated that VnaChtBP forms dimers in the absence of ligands and that this interaction is stabilized by the binding of chitin hexamers with a similar preference in the two binding sites. Our data suggest that, in addition to chitin-binding LysM (CBM50) and Avr4 (CBM14) fungal effectors, structurally unrelated CBM18 effectors have convergently evolved to prevent hydrolysis of the fungal cell wall against plant chitinases and to interfere with chitin-triggered host immunity.

The invisibility cloak: Chitin binding protein of Verticillium nonalfalfae disguises fungus from plant chitinases

2018 ◽  
Author(s):  
Helena Volk ◽  
Kristina Marton ◽  
Marko Flajšman ◽  
Sebastjan Radišek ◽  
Ingo Hein ◽  
...  
Keyword(s):  
Fungal Infections ◽  
Binding Protein ◽  
Homology Modelling ◽  
Binding Motif ◽  
Carbohydrate Binding ◽  
Fungal Cell ◽  
Verticillium Nonalfalfae ◽  
Chitin Binding Protein ◽  
Plant Chitinases

AbstractDuring fungal infections, plant cells secrete chitinases that digest chitin in the fungal cell walls. The recognition of released chitin oligomers via lysin motif (LysM)-containing immune receptors results in the activation of defence signalling pathways. We report here that Verticillium nonalfalfae, a hemibiotrophic xylem-invading fungus, prevents this recognition process by secreting a CBM18 (carbohydrate binding motif 18)-chitin binding protein, VnaChtBP, which is transcriptionally activated specifically during the parasitic life stages. VnaChtBP is encoded by the Vna8.213 gene which is highly conserved within the species, suggesting high evolutionary stability and importance for the fungal lifestyle. In a pathogenicity assay, however, Vna8.213 knockout mutants exhibit wilting symptoms similar to the wild type fungus, suggesting that Vna8.213 activity is functionally redundant during fungal infection of hop. In binding assay, recombinant VnaChtBP binds chitin and chitin oligomers in vitro with submicromolar affinity and protects fungal hyphae from degradation by plant chitinases. Using a yeast-two-hybrid assay, homology modelling and molecular docking, we demonstrated that VnaChtBP forms dimers in the absence of ligands and that this interaction is stabilized by the binding of chitin hexamers with a similar preference in the two binding sites. Our data suggest that, in addition to chitin binding LysM (CBM50) and Avr4 (CBM14) fungal effectors, structurally unrelated CBM18 effectors have convergently evolved to prevent hydrolysis of the fungal cell wall against plant chitinases.

scholarly journals Lysin Motif (LysM) Proteins: Interlinking Manipulation of Plant Immunity and Fungi

2021 ◽  
Vol 22 (6) ◽  
pp. 3114
Author(s):  
Shu-Ping Hu ◽  
Jun-Jiao Li ◽  
Nikhilesh Dhar ◽  
Jun-Peng Li ◽  
Jie-Yin Chen ◽  
...  
Keyword(s):  
Fungal Pathogens ◽  
Plant Immunity ◽  
Critical Role ◽  
Host Immunity ◽  
Carbohydrate Binding ◽  
Historical Perspectives ◽  
Plant Chitinases ◽  
Induced Immunity ◽  
Protein Modules ◽  
Coevolutionary Arms Race

The proteins with lysin motif (LysM) are carbohydrate-binding protein modules that play a critical role in the host-pathogen interactions. The plant LysM proteins mostly function as pattern recognition receptors (PRRs) that sense chitin to induce the plant’s immunity. In contrast, fungal LysM blocks chitin sensing or signaling to inhibit chitin-induced host immunity. In this review, we provide historical perspectives on plant and fungal LysMs to demonstrate how these proteins are involved in the regulation of plant’s immune response by microbes. Plants employ LysM proteins to recognize fungal chitins that are then degraded by plant chitinases to induce immunity. In contrast, fungal pathogens recruit LysM proteins to protect their cell wall from hydrolysis by plant chitinase to prevent activation of chitin-induced immunity. Uncovering this coevolutionary arms race in which LysM plays a pivotal role in manipulating facilitates a greater understanding of the mechanisms governing plant-fungus interactions.

scholarly journals A Novel Gene, CBP1, Encoding a Putative Extracellular Chitin-Binding Protein, May Play an Important Role in the Hydrophobic Surface Sensing of Magnaporthe grisea During Appressorium Differentiation

2002 ◽  
Vol 15 (5) ◽  
pp. 437-444 ◽  
Author(s):  
Takashi Kamakura ◽  
Syuichi Yamaguchi ◽  
Ken-ichiro Saitoh ◽  
Tohru Teraoka ◽  
Isamu Yamaguchi
Keyword(s):  
Germ Tube ◽  
Matrix Protein ◽  
Magnaporthe Grisea ◽  
Binding Protein ◽  
Consensus Sequence ◽  
Extracellular Matrix Protein ◽  
Specific Gene ◽  
Physical Factors ◽  
Binding Motif ◽  
Chitin Binding Protein

The conidial germ tube of the rice blast fungus, Magnaporthe grisea, differentiates a specialized cell, an appressorium, required for penetration into the host plant. Formation of the appressorium is also observed on artificial solid substrata such as polycarbonate. A novel emerging germ tube-specific gene, CBP1 (chitin-binding protein), was found in a cDNA subtractive differential library. CBP1 coded for a putative extracellular protein (signal peptide) with two similar chitin-binding domains at both ends of a central domain with homology to fungal chitin deacetylases and with a C-terminus domain rich in Ser/Thr related extracellular matrix protein such as agglutinin. The consensus sequence of the chitin-binding domain found in CBP1 has never been reported in fungi and is similar to the chitin-binding motif in plant lectins and plant chitinases classes I and IV. CBP1 was disrupted in order to identify its function. Null mutants of CBP1 failed to differentiate appressoria normally on artificial surface but succeeded in normally differentiating appressoria on the plant leaf surface. Since the null mutant Cbp1- showed abnormal appressorium differentiation only on artificial surfaces and was sensitive to the chemical inducers, CBP1 seemed to play an important role in the recognition of physical factors on solid surfaces.

Characteristics and Function of the Chitin Binding Protein from Xenorhabdus nematophila

2019 ◽  
Vol 26 (6) ◽  
pp. 414-422
Author(s):  
Jia Liu ◽  
Ping Song ◽  
Jie Zhang ◽  
Ziyan Nangong ◽  
Xiaobei Liu ◽  
...  
Keyword(s):  
Antifungal Activity ◽  
Growth Inhibition ◽  
Insecticidal Activity ◽  
Spore Germination ◽  
Binding Protein ◽  
Colloidal Chitin ◽  
Inhibition Rate ◽  
Xenorhabdus Nematophila ◽  
Chitin Binding Protein ◽  
And Function

Background: Genome sequence analysis (GenBank access No.: FN667742.1) shows that Xenorhabdus nematophila ATCC19061 contains one gene (Xn-cbp) encoding chitin binding protein (Xn-CBP). Objective: The present work aims to clarify the characteristics and function of Xn-CBP from X. nematophila HB310. Methods: In this study, the Xn-cbp gene was cloned and expressed in Escherichia coli BL21 (DE3). Substrate binding assays were performed to explain the ability of Xn-CBP combined with the polysaccharide. The insecticidal toxicity of Xn-CBP against the second-instar larvae of Helicoverpa armigera was determined by feeding method. Besides, the antifungal activity of Xn-CBP against Coniothyrium diplodiella, Verticillium dahlia, and Fusarium oxysporum was tested by spore germination assay and hyphal extension assay. Results: Xn-CBP encoded 199 amino acids with a calculated mass of 28 kDa, which contained a signal peptide and a chitin binding domain. The Bmax and Kd values of Xn-CBP to colloidal chitin were 2.46 and 4.08, respectively. Xn-CBP had insecticidal activity against the H. armigera with a growth inhibition rate of 84.08%. Xn-CBP had the highest spore germination inhibitory effect on C. diplodiella with the inhibition rate of 83.11%. The hyphal growth inhibition rate of Xn-CBP to F. oxysporum, 41.52%, was higher than the other two fungi. Conclusion: The Xn-CBP had the highest binding ability to colloidal chitin and it showed insecticidal activity and antifungal activity. The present study laid a foundation for further exploitation and utilization of X. nematophila.

Gingerol Derivatives as 14α-demethylase Inhibitors: Design and Development of Natural, Safe Antifungals for Immune-compromised Patients

2020 ◽  
Vol 17 (7) ◽  
pp. 918-928
Author(s):  
Sweta Sharma ◽  
Arpita Yadav
Keyword(s):  
Cell Membranes ◽  
Fungal Infections ◽  
Dynamics Simulation ◽  
Stable Complex ◽  
Active Site Residues ◽  
Design And Development ◽  
Triazole Derivative ◽  
Fungal Cell ◽  
Term Administration ◽  
Compromised Patients

Background: : Currently, clinically used drugs for internal fungal infections have severe side effects. Patients suffering from severe fungal infections and those at a constant risk of developing such infections require long-term administration of safe antifungals. Objective: : This work deals with the design and development of safe, non-toxic antifungals derived from natural compounds for immune-compromised patients, such as HIV patients, who are at a constant risk of developing internal fungal infections. Methods: : Molecular modeling, docking and molecular dynamics simulation studies were performed on the main constituents of ginger and their derivatives to study their capability to inhibit 14α- demethylase enzyme. Results: : Ergosterol is the key component of the fungal cell membrane for its integrity and rigidity, synthesized from lanosterol catalyzed by 14α-demethylase enzyme. In our studies, it is determined that 6-gingerol, 6-paradol, 6-shogaol and their imidazole and triazole derivatives can inhibit the synthesis of ergosterol thus weakening the fungal cell membranes. The triazole derivative of 6-gingerol forms enhanced binding interactions with the active site residues of 14α-demethylase, carries an affinity for catalytically required cofactor heme and forms a stable complex with time without the probability of premature expulsion. Thus, this compound inhibits the formation of ergosterol leading to weakened fungal cell membranes and eventually death of fungal cells. Conclusion: : The triazole derivative of 6-gingerol is recommended as a lead compound for the development of non-toxic antifungals.

scholarly journals Phylogenomic Insights into Distribution and Adaptation of Bdellovibrionota in Marine Waters

2021 ◽  
Vol 9 (4) ◽  
pp. 757
Author(s):  
Qing-Mei Li ◽  
Ying-Li Zhou ◽  
Zhan-Fei Wei ◽  
Yong Wang
Keyword(s):  
Comparative Genomics ◽  
Deep Sea ◽  
Binding Protein ◽  
Glycerol Metabolism ◽  
Metabolic Reconstruction ◽  
Type Ii Secretion ◽  
Phylogenetic Groups ◽  
Genes Encoding ◽  
Epipelagic Zone ◽  
Chitin Binding Protein

Bdellovibrionota is composed of obligate predators that can consume some Gram-negative bacteria inhabiting various environments. However, whether genomic traits influence their distribution and marine adaptation remains to be answered. In this study, we performed phylogenomics and comparative genomics studies using 132 Bdellovibrionota genomes along with five metagenome-assembled genomes (MAGs) from deep sea zones. Four phylogenetic groups, Oligoflexia, Bdello-group1, Bdello-group2 and Bacteriovoracia, were revealed by constructing a phylogenetic tree, of which 53.84% of Bdello-group2 and 48.94% of Bacteriovoracia were derived from the ocean. Bacteriovoracia was more prevalent in deep sea zones, whereas Bdello-group2 was largely distributed in the epipelagic zone. Metabolic reconstruction indicated that genes involved in chemotaxis, flagellar (mobility), type II secretion system, ATP-binding cassette (ABC) transporters and penicillin-binding protein were necessary for the predatory lifestyle of Bdellovibrionota. Genes involved in glycerol metabolism, hydrogen peroxide (H2O2) degradation, cell wall recycling and peptide utilization were ubiquitously present in Bdellovibrionota genomes. Comparative genomics between marine and non-marine Bdellovibrionota demonstrated that betaine as an osmoprotectant is probably widely used by marine Bdellovibrionota, and all the marine genomes have a number of genes for adaptation to marine environments. The genes encoding chitinase and chitin-binding protein were identified for the first time in Oligoflexia, which implied that Oligoflexia may prey on a wider spectrum of microbes. This study expands our knowledge on adaption strategies of Bdellovibrionota inhabiting deep seas and the potential usage of Oligoflexia for biological control.

A photo-cleavable biotin affinity tag for the facile release of a photo-crosslinked carbohydrate-binding protein

2016 ◽  
Vol 24 (6) ◽  
pp. 1216-1224 ◽  
Author(s):  
Tsung-Che Chang ◽  
Avijit K. Adak ◽  
Ting-Wei Lin ◽  
Pei-Jhen Li ◽  
Yi-Ju Chen ◽  
...  
Keyword(s):  
Binding Protein ◽  
Carbohydrate Binding ◽  
Affinity Tag ◽  
Carbohydrate Binding Protein

scholarly journals SARP, a new alternatively spliced protein phosphatase 1 and DNA interacting protein

2007 ◽  
Vol 402 (1) ◽  
pp. 187-196 ◽  
Author(s):  
Gareth J. Browne ◽  
Margarida Fardilha ◽  
Senga K. Oxenham ◽  
Wenjuan Wu ◽  
Nicholas R. Helps ◽  
...  
Keyword(s):  
Protein Phosphatase ◽  
Mammalian Cells ◽  
Leucine Zipper ◽  
Transforming Growth Factor ◽  
Binding Protein ◽  
Transforming Growth Factor Β ◽  
Ankyrin Repeat ◽  
Protein Phosphatase 1 ◽  
Binding Motif ◽  
Alternative Mrna Splicing

PP1 (protein phosphatase 1) is a ubiquitously expressed serine/threonine-specific protein phosphatase whose activity towards different substrates appears to be mediated via binding to specific proteins that play critical regulatory and targeting roles. In the present paper we report the cloning and characterization of a new protein, termed SARP (several ankyrin repeat protein), which is shown to interact with all isoforms of PP1 by a variety of techniques. A region encompassing a consensus PP1-binding motif in SARP (K354VHF357) modulates endogenous SARP–PP1 activity in mammalian cells. This SARP–PP1 interaction motif lies partially within the first ankyrin repeat in contrast with other proteins [53BP2 (p53 binding protein 2), MYPT1/M110/MBS (myosin binding protein of PP1) and TIMAP (transforming growth factor β inhibited, membrane-associated protein)], where a PP1-binding motif precedes the ankyrin repeats. Alternative mRNA splicing produces several isoforms of SARP from a single human gene at locus 11q14. SARP1 and/or SARP2 (92–95 kDa) are ubiquitously expressed in all tissues with high levels in testis and sperm, where they are shown to interact with both PP1γ1 and PP1γ2. SARP3 (65 kDa) is most abundant in brain where SARP isoforms interact with both PP1α and PP1γ1. SARP is highly abundant in the nucleus of mammalian cells, consistent with the putative nuclear localization signal at the N-terminus. The presence of a leucine zipper near the C-terminus of SARP1 and SARP2, and the binding of mammalian DNA to SARP2, suggests that SARP1 and SARP2 may be transcription factors or DNA-associated proteins that modulate gene expression.

scholarly journals Insight into the Dual Functions of Bacterial Enhancer-Binding Protein Rrp2 of Borrelia burgdorferi

2016 ◽  
Vol 198 (10) ◽  
pp. 1543-1552 ◽  
Author(s):  
Yanping Yin ◽  
Youyun Yang ◽  
Xuwu Xiang ◽  
Qian Wang ◽  
Zhang-Nv Yang ◽  
...  
Keyword(s):  
Dna Binding ◽  
Borrelia Burgdorferi ◽  
Binding Protein ◽  
Phosphorylation Site ◽  
Binding Motif ◽  
Cell Replication ◽  
Additional Function ◽  
Content Type ◽  
Terminal Domain ◽  
Enhancer Binding Protein

ABSTRACTIt is well established that the RpoN-RpoS sigma factor (σ54-σS) cascade plays an essential role in differential gene expression during the enzootic cycle ofBorrelia burgdorferi, the causative agent of Lyme disease. The RpoN-RpoS pathway is activated by the response regulator/σ54-dependent activator (also called bacterial enhancer-binding protein [bEBP]) Rrp2. One unique feature of Rrp2 is that this activator is essential for cell replication, whereas RpoN-RpoS is dispensable for bacterial growth. How Rrp2 controls cell replication, a function that is independent of RpoN-RpoS, remains to be elucidated. In this study, by generating a series of conditionalrrp2mutant strains, we demonstrated that the N-terminal receiver domain of Rrp2 is required for spirochetal growth. Furthermore, a D52A point mutation at the phosphorylation site within the N terminus of Rrp2 abolished cell replication. Mutation of the ATPase motif within the central domain of Rrp2 did not affect spirochetal replication, indicating that phosphorylation-dependent ATPase activity of Rrp2 for σ54activation is not required for cell growth. However, deletion of the C-terminal domain or a 16-amino-acid truncation of the helix-turn-helix (HTH) DNA-binding motif within the C-terminal domain of Rrp2 abolished spirochetal replication. It was shown that constitutive expression ofrpoSis deleterious to borrelial growth. We showed that the essential nature of Rrp2 is not due to an effect onrpoS. These data suggest that phosphorylation-dependent oligomerization and DNA binding of Rrp2 likely function as a repressor, independently of the activation of σ54, controlling an essential step of cell replication inB. burgdorferi.IMPORTANCEBacterial enhancer-binding proteins (bEBPs) are a unique group of transcriptional activators specifically required for σ54-dependent gene transcription. This work demonstrates that theB. burgdorferibEBP, Rrp2, has an additional function that is independent of σ54, that of its essentiality for spirochetal growth, and such a function is dependent on its N-terminal signal domain and C-terminal DNA-binding domain. These findings expand our knowledge on bEBP and provide a foundation to further study the underlying mechanism of this new function of bEBP.

Sign in / Sign up

Export Citation Format

Share Document