Requirement for either a host- or pectin-induced pectate lyase for infection of
            <i>Pisum sativum</i>
            by
            <i>Nectria hematococca</i>

Rogers, Linda; Kim, Yeon-Ki; Guo, Wenjin; González-Candelas, Luı́s; Li, Daoxin; Kolattukudy, Pappachan E.

doi:10.1073/pnas.160271497

Cited by 127 publications

(91 citation statements)

References 58 publications

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“…It has been showed in a number of plant and animal systems that extracellular proteins play an essential role in pathogenic development. These include several plant cell wall degrading enzymes from phytopathogens (Rogers et al, 2000;Oeser et al, 2002;Isshiki et al, 2001), aspartyl proteases from the animal pathogen C. albicans and an extracellular phospholipase from Cryptococcus neoformans (Cox et al, 2001). While our data suggest that the reduced virulence of CLPT1 dominant negative mutants could arise from a strong decrease of cell wall degrading enzyme secretion, other extracellular or cell surface proteins are known to also play a major role in pathogenesis.…”

Section: Discussionmentioning

confidence: 70%

Functional analysis ofCLPT1, a Rab/GTPase required for protein secretion and pathogenesis in the plant fungal pathogenColletotrichum lindemuthianum

Siriputthaiwan

Jauneau

Herbert

et al. 2005

Journal of Cell Science

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In eukaryotic cells, Rab/GTPases are major regulators of vesicular trafficking and are involved in essential processes including exocytosis, endocytosis and cellular differentiation. To investigate the role of these proteins in fungal pathogenicity, a dominant-negative mutant allele of CLPT1, a Rab/GTPase of the bean pathogen Colletotrichum lindemuthianum, was expressed in transgenic strains. This mutated gene encodes the amino-acid substitution N123I analogous to the N133I substitution in a known trans-dominant inhibitor of the Sec4 Rab/GTPase from Saccharomyces cerevisiae. A pectinase gene promoter was used to drive the CLPT1(N123I) allele in C. lindemuthianum, allowing the expression of the foreign gene on pectin medium and during pathogenesis, but not on glucose. The same strategy was used to overexpress the wild-type CLPT1 allele. During growth on pectin medium, production of extracellular pectinases was strongly impaired only in CLPT1(N123I)-expressing strains. Cytological analysis revealed that CLPT1(N123I) strains accumulated intracellular aggregates only on pectin, resulting from the fusion of vesicles containing polysaccharides or glycoproteins. Moreover, these strains showed a severe reduction of pathogenesis and were unable to penetrate the host cells. These results indicated that the Rab/GTPase CLPT1 is essential for fungal pathogenesis by regulating the intracellular transport of secretory vesicles involved in the delivery of proteins to the extracellular medium and differentiation of infectious structures.

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Section: Discussionmentioning

confidence: 70%

Functional analysis ofCLPT1, a Rab/GTPase required for protein secretion and pathogenesis in the plant fungal pathogenColletotrichum lindemuthianum

Siriputthaiwan

Jauneau

Herbert

et al. 2005

Journal of Cell Science

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“…Among them, pectinases are the subject of intense research, because pectin degradation contributes to fungal pathogenicity in several host-pathogen systems (1)(2)(3)(4) and is of considerable interest for various biotechnological processes. Pectinase gene expression is regulated at the transcriptional level by environmental conditions such as the pH of the medium (5,6) and by carbon sources, being induced by pectin and pectic components (polygalacturonic acid, galacturonic acid, arabinose, and rhamnose) and repressed by glucose (6 -8).…”

mentioning

confidence: 99%

A cis-Acting Sequence Homologous to the Yeast Filamentation and Invasion Response Element Regulates Expression of a Pectinase Gene from the Bean PathogenColletotrichum lindemuthianum

Herbert

Jacquet

Borel

et al. 2002

Journal of Biological Chemistry

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Phytopathogenic fungi secrete hydrolytic enzymes that degrade plant cell walls, notably pectinases. The signaling pathway(s) that control pectinase gene expression are currently unknown in filamentous fungi. Recently, the green fluorescent protein coding sequence was used as a reporter gene to study the expression of CLPG2, a gene encoding an endopolygalacturonase of the bean pathogen Colletotrichum lindemuthianum. CLPG2 is transcriptionally induced by pectin in the axenic culture of the fungus and during formation of the appressorium, an infection structure specialized in plant tissue penetration. In the present study, promoter deletion and mutagenesis, as well as gel shift mobility assays, allowed for the first time identification of cisacting elements that bind protein factors and are essential for the regulation of a pectinase gene. We found that two different adjacent DNA motifs are combined to form an active element that shows a strong sequence homology with the yeast filamentation and invasion response element. The same element is required for the transcriptional activation of CLPG2 by pectin and during appressorium development. This study strongly suggests that the control of virulence genes of fungal plant pathogens, such as pectinases, involves the formation of a complex of transcriptional activators similar to those regulating the invasive growth in yeast.Saprophytic and phytopathogenic filamentous fungi secrete extracellular enzymes that degrade plant cell wall polymers. Among them, pectinases are the subject of intense research, because pectin degradation contributes to fungal pathogenicity in several host-pathogen systems (1-4) and is of considerable interest for various biotechnological processes. Pectinase gene expression is regulated at the transcriptional level by environmental conditions such as the pH of the medium (5, 6) and by carbon sources, being induced by pectin and pectic components (polygalacturonic acid, galacturonic acid, arabinose, and rhamnose) and repressed by glucose (6 -8). Whereas the regulatory pathways that control pectinase gene expression are well documented in phytopathogenic bacteria (9), little is known about the regulation of fungal pectinases. Recently, ccSNF1, a gene encoding a protein homologous to the yeast protein kinase SNF1 required for expression of glucose-repressed genes, was isolated from the maize pathogen Cochliobolus carbonum (10). Mutants disrupted in this gene showed a reduced pathogenicity, and genes coding for hydrolytic enzymes were down-regulated.Colletotrichum lindemuthianum is a pathogenic fungus that is the causal agent of bean anthracnose. Conidia germinate on the surface of the aerial part of the plant and differentiate a specialized cell called appressorium, which allows the parasite to penetrate plant tissues (11). During the first stages of infection, C. lindemuthianum establishes a biotrophic interaction with the host plant. 3-4 days post-inoculation, the parasite develops secondary hyphae and becomes necrotrophic, causing tissue necrosis. ...

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“…It is not unusual for mutation of an individual gene or several genes encoding hydrolases to have little or no effect on pathogenicity. This may be due to either functional redundancy (91)(92)(93)(94) or extreme functional specialization (95-97) among gene families and individual CWDE genes. Cell wall-degrading enzymes can be grouped in families of multiple members with interconnected activities.…”

Section: Cell Wall-degrading Enzyme Genesmentioning

confidence: 99%

How the Necrotrophic Fungus Alternaria brassicicola Kills Plant Cells Remains an Enigma

Cho

2015

Eukaryot Cell

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Alternaria species are mainly saprophytic fungi, but some are plant pathogens. Seven pathotypes of Alternaria alternata use secondary metabolites of host-specific toxins as pathogenicity factors. These toxins kill host cells prior to colonization. Genes associated with toxin synthesis reside on conditionally dispensable chromosomes, supporting the notion that pathogenicity might have been acquired several times by A. alternata. Alternaria brassicicola, however, seems to employ a different mechanism. Evidence on the use of host-specific toxins as pathogenicity factors remains tenuous, even after a diligent search aided by full-genome sequencing and efficient reverse-genetics approaches. Similarly, no individual genes encoding lipases or cell wall-degrading enzymes have been identified as strong virulence factors, although these enzymes have been considered important for fungal pathogenesis. This review describes our current understanding of toxins, lipases, and cell wall-degrading enzymes and their roles in the pathogenesis of A. brassicicola compared to those of other pathogenic fungi. It also describes a set of genes that affect pathogenesis in A. brassicicola. They are involved in various cellular functions that are likely important in most organisms and probably indirectly associated with pathogenesis. Deletion or disruption of these genes results in weakly virulent strains that appear to be sensitive to the defense mechanisms of host plants. Finally, this review discusses the implications of a recent discovery of three important transcription factors associated with pathogenesis and the putative downstream genes that they regulate.

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Requirement for either a host- or pectin-induced pectate lyase for infection of Pisum sativum by Nectria hematococca

Cited by 127 publications

References 58 publications

Functional analysis ofCLPT1, a Rab/GTPase required for protein secretion and pathogenesis in the plant fungal pathogenColletotrichum lindemuthianum

Functional analysis ofCLPT1, a Rab/GTPase required for protein secretion and pathogenesis in the plant fungal pathogenColletotrichum lindemuthianum

A cis-Acting Sequence Homologous to the Yeast Filamentation and Invasion Response Element Regulates Expression of a Pectinase Gene from the Bean PathogenColletotrichum lindemuthianum

How the Necrotrophic Fungus Alternaria brassicicola Kills Plant Cells Remains an Enigma

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