scholarly journals Verticillium dahliae LysM effectors differentially contribute to virulence on plant hosts

2016 ◽  
Author(s):  
Anja Kombrink ◽  
Hanna Rovenich ◽  
Xiaoqian Shi-Kunne ◽  
Eduardo Rojas-Padilla ◽  
Grardy C.M. van den Berg ◽  
...  
Keyword(s):  
Verticillium Dahliae ◽  
Plant Pathogens ◽  
Hydrolytic Enzymes ◽  
Pathogenic Fungi ◽  
Vascular Wilt ◽  
In Planta ◽  
Targeted Deletion ◽  
Effector Genes ◽  
Specific Effector ◽  
The Individual

SUMMARYChitin-binding LysM effectors contribute to virulence of various plant pathogenic fungi that are causal agents of foliar diseases. Here, we report on LysM effectors of the soil-borne fungal vascular wilt pathogen Verticillium dahliae. Comparative genomics revealed three core LysM effectors that are conserved in a collection of V. dahliae strains. Remarkably, and in contrast to the previously studied LysM effectors of other plant pathogens, no expression of core LysM effectors was monitored in planta in a taxonomically diverse panel of host plants. Moreover, targeted deletion of the individual LysM effector genes in V. dahliae strain JR2 did not compromise virulence in infections on Arabidopsis, tomato or Nicotiana benthamiana. Interestingly, an additional lineage-specific LysM effector is encoded in the genome of V. dahliae strain VdLs17 but not in any other V. dahliae strain sequenced to date. Remarkably, this lineage-specific effector is expressed in planta and contributes to virulence of V. dahliae strain VdLs17 on tomato, but not on Arabidopsis or on N. benthamiana. Functional analysis revealed that this LysM effector binds chitin, is able to suppress chitin-induced immune responses, and protects fungal hyphae against hydrolysis by plant hydrolytic enzymes. Thus, in contrast to the core LysM effectors of V. dahliae, this lineage-specific LysM effector of strain VdLs17 contributes to virulence in planta.

scholarly journals Comparative genomics of Verticillium dahliae isolates reveals the in planta-secreted effector protein recognized in V2 tomato plants

2020 ◽  
Author(s):  
Edgar A. Chavarro-Carrero ◽  
Jasper P. Vermeulen ◽  
David E. Torres ◽  
Toshiyuki Usami ◽  
Henk J. Schouten ◽  
...  
Keyword(s):  
Comparative Genomics ◽  
Verticillium Dahliae ◽  
Plant Pathogens ◽  
Effector Protein ◽  
Vascular Wilt ◽  
In Planta ◽  
Specific Sequence ◽  
Tomato Plants ◽  
Tomato Cultivars ◽  
Race 2

SUMMARYPlant pathogens secrete effector molecules during host invasion to promote host colonization. However, some of these effectors become recognized by host receptors, encoded by resistance genes, to mount defense response and establish immunity. Recently, a novel resistance was identified in tomato, mediated by the single dominant V2 locus, to control strains of the soil-borne vascular wilt fungus Verticillium dahliae that belong to race 2. We performed comparative genomics between race 2 strains and resistance-breaking race 3 strains to identify the avirulence effector that activates V2 resistance, termed Av2. We identified 277 kb of race 2-specific sequence comprising only two genes that encode predicted secreted proteins, both of which are expressed by V. dahliae during tomato colonization. Subsequent functional analysis based on genetic complementation into race 3 isolates confirmed that one of the two candidates encodes the avirulence effector Av2 that is recognized in V2 tomato plants. The identification of Av2 will not only be helpful to select tomato cultivars that are resistant to race 2 strains of V. dahliae, as the corresponding V2 resistance gene has not yet been mapped, but also to monitor adaptations in the V. dahliae population to deployment of V2-containing tomato cultivars in agriculture.

scholarly journals Dynamic virulence-related regions of the fungal plant pathogen Verticillium dahliae display remarkably enhanced sequence conservation

2018 ◽  
Author(s):  
Jasper R.L. Depotter ◽  
Xiaoqian Shi-Kunne ◽  
Hélène Missonnier ◽  
Tingli Liu ◽  
Luigi Faino ◽  
...  
Keyword(s):  
Verticillium Dahliae ◽  
Plant Pathogens ◽  
Sequence Divergence ◽  
Sequence Conservation ◽  
In Planta ◽  
Effector Genes ◽  
Accelerated Evolution ◽  
Mediate Immunity ◽  
Element Activity ◽  
Genomic Regions

ABSTRACTSelection pressure impacts genomes unevenly, as different genes adapt with differential speed to establish an organism’s optimal fitness. Plant pathogens co-evolve with their hosts, which implies continuously adaption to evade host immunity. Effectors are secreted proteins that mediate immunity evasion, but may also typically become recognized by host immune receptors. To facilitate effector repertoire alterations, in many pathogens, effector genes reside in dynamic genomic regions that are thought to display accelerated evolution, a phenomenon that is captured by the two-speed genome hypothesis. The genome of the vascular wilt pathogen Verticillium dahliae has been proposed to obey to a similar two-speed regime with dynamic, lineage-specific regions that are characterized by genomic rearrangements, increased transposable element activity and enrichment in in planta-induced effector genes. However, little is known of the origin of, and sequence diversification within, these lineage-specific regions. Based on comparative genomics among Verticillium spp. we now show differential sequence divergence between core and lineage-specific genomic regions of V. dahliae. Surprisingly, we observed that lineage-specific regions display markedly increased sequence conservation. Since single nucleotide diversity is reduced in these regions, host adaptation seems to be merely achieved through presence/absence polymorphisms. Increased sequence conservation of genomic regions important for pathogenicity is an unprecedented finding for filamentous plant pathogens and signifies the diversity of genomic dynamics in host-pathogen co-evolution.

scholarly journals Verticillium dahliae Sge1 Differentially Regulates Expression of Candidate Effector Genes

2013 ◽  
Vol 26 (2) ◽  
pp. 249-256 ◽  
Author(s):  
Parthasarathy Santhanam ◽  
Bart P. H. J. Thomma
Keyword(s):  
Gene Expression ◽  
Verticillium Dahliae ◽  
Radial Growth ◽  
Transcriptional Regulator ◽  
Vascular Wilt ◽  
In Planta ◽  
Effector Gene ◽  
Effector Genes ◽  
Induced Genes

The ascomycete fungus Verticillium dahliae causes vascular wilt diseases in hundreds of dicotyledonous plant species. However, thus far, only few V. dahliae effectors have been identified, and regulators of pathogenicity remain unknown. In this study, we investigated the role of the V. dahliae homolog of Sge1, a transcriptional regulator that was previously implicated in pathogenicity and effector gene expression in Fusarium oxysporum. We show that V. dahliae Sge1 (VdSge1) is required for radial growth and production of asexual conidiospores, because VdSge1 deletion strains display reduced radial growth and reduced conidia production. Furthermore, we show that VdSge1 deletion strains have lost pathogenicity on tomato. Remarkably, VdSge1 is not required for induction of Ave1, the recently identified V. dahliae effector that activates resistance mediated by the Ve1 immune receptor in tomato. Further assessment of the role of VdSge1 in the induction of the nine most highly in-planta-induced genes that encode putative effectors revealed differential activity. Although the expression of one putative effector gene in addition to Ave1 was not affected by VdSge1 deletion, VdSge1 appeared to be required for the expression of six putative effector genes, whereas two of the putative effectors genes were found to be negatively regulated by VdSge1. In conclusion, our data suggest that VdSge1 differentially regulates V. dahliae effector gene expression.

scholarly journals Evidence for Functional Diversification Within a Fungal NEP1-Like Protein Family

2013 ◽  
Vol 26 (3) ◽  
pp. 278-286 ◽  
Author(s):  
Parthasarathy Santhanam ◽  
H. Peter van Esse ◽  
Isabell Albert ◽  
Luigi Faino ◽  
Thorsten Nürnberger ◽  
...  
Keyword(s):  
Gene Family ◽  
Vegetative Growth ◽  
Nicotiana Benthamiana ◽  
Family Members ◽  
Aerial Mycelium ◽  
Vascular Wilt ◽  
In Planta ◽  
Functional Diversification ◽  
Targeted Deletion ◽  
Genes Encoding

In this study, we functionally analyzed the gene family encoding necrosis- and ethylene-inducing-like proteins (NLP) of the vascular wilt pathogen Verticillium dahliae. We show that the composition of the NLP gene family varies little among V. dahliae isolates. The cytotoxic activity of NLP family members of a tomato-pathogenic V. dahliae strain was determined, demonstrating that only two of the seven NLP induced plant cell death. The genes encoding these cytotoxic NLP were found to be induced in V. dahliae upon colonization of tomato. Interestingly, targeted deletion of either of the two genes in V. dahliae significantly compromised virulence on tomato as well as on Arabidopsis plants, whereas deletion of only one of the two genes affected virulence on Nicotiana benthamiana. This could be attributed to differential induction of the two NLP genes in V. dahliae upon N. benthamiana colonization, revealing that the in planta induction of NLP genes varies between plant hosts. Intriguingly, one of the NLP genes appears to also affect vegetative growth and conidiospore production, because the corresponding deletion strain produced significantly fewer conidiospores and developed extensive aerial mycelium. In conclusion, we demonstrate that the expanded V. dahliae NLP family shows functional diversification, revealing not only differential cytotoxicity between family members but also that the cytotoxic NLP play a role in vegetative growth and asexual reproduction in addition to their contribution to virulence.

Extracellular hydrolytic enzymes in the fungal genus Verticillium: adaptations for pathogenesis

1999 ◽  
Vol 45 (10) ◽  
pp. 856-864 ◽  
Author(s):  
Michael J Bidochka ◽  
Susan Burke ◽  
Luna Ng
Keyword(s):  
Plant Pathogen ◽  
Plant Pathogens ◽  
Plant Cell Wall ◽  
Extracellular Enzymes ◽  
Hydrolytic Enzymes ◽  
Pathogenic Fungi ◽  
Verticillium Lecanii ◽  
Opportunistic Pathogens ◽  
Broad Array ◽  
Fungal Genus

The insect and plant pathogens within the fungal genus Verticillium showed enzymatic adaptation (production and regulation) directed to the degradation of some of the polymers found in the integument of their respective hosts. For example, the facultative plant pathogens (V. albo-atrum and V. dahliae) produced greater levels of cellulase and xylanase than the facultative insect pathogen (V. lecanii). Verticillium lecanii produced extracellular subtilisin-like protease when grown in insect cuticle medium but not in plant cell wall medium, while the plant pathogen V. albo-atrum showed a diminished regulatory component in the production of this enzyme. The opportunistic pathogens (V. fungicola and V. coccosporum) and the saprobic species (V. rexianum) were less specific in the production and regulation of several proteases as well as cellulases and xylanases. A dendrogram based on cluster analysis compiled from fungal API-ZYM profiles showed commonalties in a broad array of extracellular enzymes within a host-pathogen group (i.e. insect or plant pathogen). The opportunistic pathogens were dispersed throughout the dendrogram, suggestive of the diversity in type and expression of extracellular enzymes.Key words: extracellular enzymes, pathogenic fungi.

The Biocontrol Mechanism of Trichoderma asperellum Resistance Plant Pathogenic Fungi

2013 ◽  
Vol 726-731 ◽  
pp. 4525-4528
Author(s):  
Ping Yang ◽  
Qian Xu
Keyword(s):  
Cell Wall ◽  
Plant Pathogens ◽  
Control Plant ◽  
Hydrolytic Enzymes ◽  
Pathogenic Fungi ◽  
Dry Weight ◽  
Plant Pathogenic Fungi ◽  
Cell Wall Degrading Enzymes ◽  
Antifungal Metabolites ◽  
Degrading Enzymes

T. asperellum is an important biocontrol fungus owing to their ability to antagonize plant pathogenic fungi. The biocontrol effects of T. asperellum were played by secreting many kinds of hydrolytic enzymes and antibiotics. T. asperellum producing more cell wall degrading enzymes when meeting plant pathogens. Moreover, the growth of the plant pathogens was inhibited by T. asperellum secondary metabolites. The yield of antibiotic 6-PP was 1.32 mg 6-PP/g mycelial dry weight. T. asperellum control plant pathogens through secreting cell wall degrading enzymes and producing antifungal metabolites.

scholarly journals Clathrin Is Important for Virulence Factors Delivery in the Necrotrophic Fungus Botrytis cinerea

2021 ◽  
Vol 12 ◽  
Author(s):  
Eytham Souibgui ◽  
Christophe Bruel ◽  
Mathias Choquer ◽  
Amélie de Vallée ◽  
Cindy Dieryckx ◽  
...  
Keyword(s):  
Botrytis Cinerea ◽  
Virulence Factors ◽  
Essential Role ◽  
Plant Pathogens ◽  
Pathogenic Fungus ◽  
Hydrolytic Enzymes ◽  
Pathogenic Fungi ◽  
Dominant Negative ◽  
Intracellular Vesicles

Fungi are the most prevalent plant pathogens, causing annually important damages. To infect and colonize their hosts, they secrete effectors including hydrolytic enzymes able to kill and macerate plant tissues. These secreted proteins are transported from the Endoplasmic Reticulum and the Golgi apparatus to the extracellular space through intracellular vesicles. In pathogenic fungi, intracellular vesicles were described but their biogenesis and their role in virulence remain unclear. In this study, we report the essential role of clathrin heavy chain (CHC) in the pathogenicity of Botrytis cinerea, the agent of gray mold disease. To investigate the importance of this protein involved in coat vesicles formation in eukaryotic cells, a T-DNA insertional mutant reduced in the expression of the CHC-encoding gene, and a mutant expressing a dominant-negative form of CHC were studied. Both mutants were strongly affected in pathogenicity. Characterization of the mutants revealed altered infection cushions and an important defect in protein secretion. This study demonstrates the essential role of clathrin in the infectious process of a plant pathogenic fungus and more particularly its role in virulence factors delivery.

scholarly journals The Pleiades are a cluster of fungal effectors that inhibit host defenses

2021 ◽  
Vol 17 (6) ◽  
pp. e1009641
Author(s):  
Fernando Navarrete ◽  
Nenad Grujic ◽  
Alexandra Stirnberg ◽  
Indira Saado ◽  
David Aleksza ◽  
...  
Keyword(s):  
Plant Pathogens ◽  
Functional Characterization ◽  
Rapid Evolution ◽  
Effector Proteins ◽  
In Planta ◽  
E3 Ligases ◽  
Effector Genes ◽  
Ros Burst ◽  
Molecular Patterns

Biotrophic plant pathogens secrete effector proteins to manipulate the host physiology. Effectors suppress defenses and induce an environment favorable to disease development. Sequence-based prediction of effector function is impeded by their rapid evolution rate. In the maize pathogen Ustilago maydis, effector-coding genes frequently organize in clusters. Here we describe the functional characterization of the pleiades, a cluster of ten effector genes, by analyzing the micro- and macroscopic phenotype of the cluster deletion and expressing these proteins in planta. Deletion of the pleiades leads to strongly impaired virulence and accumulation of reactive oxygen species (ROS) in infected tissue. Eight of the Pleiades suppress the production of ROS upon perception of pathogen associated molecular patterns (PAMPs). Although functionally redundant, the Pleiades target different host components. The paralogs Taygeta1 and Merope1 suppress ROS production in either the cytoplasm or nucleus, respectively. Merope1 targets and promotes the auto-ubiquitination activity of RFI2, a conserved family of E3 ligases that regulates the production of PAMP-triggered ROS burst in plants.

scholarly journals Diversity and biological activity of culturable endophytic bacteria associated with marigold (Calendula officinalis L.)

2021 ◽  
Vol 7 (3) ◽  
pp. 336-353
Author(s):  
Vyacheslav Shurigin ◽  
◽  
Burak Alaylar ◽  
Kakhramon Davranov ◽  
Stephan Wirth ◽  
...  
Keyword(s):  
Plant Growth ◽  
Endophytic Bacteria ◽  
Plant Pathogens ◽  
Hydrolytic Enzymes ◽  
Pathogenic Fungi ◽  
Rrna Gene ◽  
Plant Pathogenic Fungi ◽  
Bacterial Isolates ◽  
Calendula Officinalis ◽  
Fungal Plant Pathogens

<abstract> <p>Endophytes colonizing plant tissue play an essential role in plant growth, development, stress tolerance and plant protection from soil-borne diseases. In this study, we report the diversity of cultivable endophytic bacteria associated with marigold (<italic>Calendula officinalis</italic> L.) by using 16S rRNA gene analysis and their plant beneficial properties. A total of 42 bacterial isolates were obtained from plant tissues of marigold. They belonged to the genera <italic>Pantoea, Enterobacter, Pseudomonas, Achromobacter, Xanthomonas, Rathayibacter, Agrobacterium, Pseudoxanthomonas</italic>, and <italic>Beijerinckia</italic>. Among the bacterial strains, <italic>P. kilonensis</italic> FRT12, and <italic>P. rhizosphaerae</italic> FST5 showed moderate or vigorous inhibition against three tested plant pathogenic fungi, <italic>F. culmorum, F. solani</italic> and <italic>R. solani</italic>. They also demonstrated the capability to produce hydrolytic enzymes and indole-3-acetic acid (IAA). Five out of 16 isolates significantly stimulated shoot and root growth of marigold in a pot experiment. The present study reveals that more than half of the bacterial isolates associated with marigold (<italic>C. officinalis</italic> L.) provided antifungal activity against one or more plant pathogenic fungi. Our findings suggest that medicinal plants with antimicrobial activity could be a source for selecting microbes with antagonistic activity against fungal plant pathogens or with plant growth stimulating potential. These isolates might be considered as promising candidates for the improvement of plant health.</p> </abstract>

scholarly journals Ultrastructural and Cytochemical Aspects of the Interaction Between the Mycoparasite Pythium oligandrum and Soilborne Plant Pathogens

1999 ◽  
Vol 89 (6) ◽  
pp. 506-517 ◽  
Author(s):  
Nicole Benhamou ◽  
Patrice Rey ◽  
Karine Picard ◽  
Yves Tirilly
Keyword(s):  
Electron Microscope ◽  
Plant Pathogens ◽  
Light And Electron Microscopy ◽  
Hydrolytic Enzymes ◽  
Pathogenic Fungi ◽  
Pythium Oligandrum ◽  
Intimate Contact ◽  
Phytophthora Megasperma ◽  
Fungal Plant Pathogens ◽  
Cellulose Component

The interaction between the oomycete Pythium oligandrum and various soilborne oomycete and fungal plant pathogens (P. ultimum, P. aphanidermatum, Fusarium oxysporum f. sp. radicis-lycopersici, Verticillium albo-atrum, Rhizoctonia solani, and Phytophthora megasperma) was studied by light and electron microscopy in order to assess the relative contribution of mycoparasitism and antibiosis in the antagonistic process. Scanning electron microscope investigations of the interaction regions showed that structural alterations of all pathogenic fungi and oomycetes (except for Phytophthora megasperma) occurred soon after contact with the antagonist. Light and transmission electron microscope studies of the interaction region between the antagonist and P. ultimum revealed that intimate contact between both partners preceded a sequence of degradation events including aggregation of host cytoplasm and penetration of altered host hyphae. Localization of the host wall cellulose component showed that cellulose was altered at potential penetration sites. A similar scheme of events was observed during the interaction between P. oligandrum and F. oxysporum f. sp. radicis-lycopersici, with the exception that complete loss of host protoplasm was associated with antagonist invasion. The interaction between P. oligandrum and R. solani resulted in an abnormal deposition of a wall-like material at potential penetration sites for the antagonist. However, the antagonist displayed the ability to circumvent this barrier and penetrate host hyphae by locally altering the chitin component of the host hyphal wall. Interestingly, antagonist cells also showed extensive alteration as evidenced by the frequent occurrence of empty hyphal shells. In the case of Phytophthora megasperma, hyphal interactions did not occur, but hyphae of the plant pathogen were damaged severely. At least two distinct mechanisms appear to be involved in the process of oomycete and fungal attack by P. oligandrum: (i) mycoparasitism, mediated by intimate hyphal interactions, and (ii) antibiosis, with alteration of the host hyphae prior to contact with the antagonist. However, the possibility that the antagonistic process may rely on the dual action of antibiotics and hydrolytic enzymes is discussed.

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