An ultrastructural comparison of monokaryotic and dikaryotic haustoria formed by the fusiform rust fungus Cronartium quercuum f.sp. fusiforme

1982 ◽  
Vol 60 (12) ◽  
pp. 2914-2922 ◽  
Author(s):  
D. J. Gray ◽  
H. V. Amerson ◽  
C. G. Van Dyke
Keyword(s):  
Cell Wall ◽  
Host Cell ◽  
Pinus Taeda ◽  
Mother Cell ◽  
Rust Fungus ◽  
Neck Region ◽  
Cronartium Quercuum ◽  
Host Cell Wall ◽  
Mother Cells ◽  
Mother Cell Wall

Haustoria formed by the monokaryotic stage of Cronartium quercuum f. sp. fusiforme in Pinus taeda differed from those of the dikaryotic phase in Quercus rubra. Monokaryotic (M) haustorial walls were continuous with the walls of relatively undifferentiated haustorial mother cells. The septate M-haustorial neck and expanded M-haustorial body were separated from the invaginated host plasmalemma by a sheath which was continuous with the host cell wall. Collars encasing sheaths were infrequently observed. Dikaryotic (D) haustoria were morphologically similar to M-haustoria; however, they differed in several respects when examined with TEM. The D-haustorial mother cell wall was thickened at the penetration site but a reduction in the number of wall layers occurred between the thickened portion of the mother cell and the D-haustorium. A darkly staining neckband was present in the wall of the nonseptate D-haustorial neck but was lacking in the M-haustorium. An extensive sheath separated the invaginated host plasmalemma from the D-haustorial wall distally from the neckband. However, the sheath was separated from the D-haustorial wall and from the host cell wall by an invaginated host plasmalemma doubled in the haustorial neck region proximally from the neckband.

Haustorial mother cell development by Uromyces vignae on collodion membranes

1988 ◽  
Vol 66 (4) ◽  
pp. 736-741 ◽  
Author(s):  
Michèle C. Heath ◽  
C. J. Perumalla
Keyword(s):  
Cell Wall ◽  
Mother Cell ◽  
Rust Fungus ◽  
Potential Binding ◽  
Disulphonic Acid ◽  
Uromyces Vignae ◽  
Mother Cells ◽  
Chloroform Methanol ◽  
Infection Hypha ◽  
Mother Cell Wall

The development of infection structures by the rust fungus Uromyces vignae was observed on oil-containing collodion membranes. About 40% of infection hyphae formed a haustorial mother cell, but this structure commonly senesced and died more rapidly than the infection hypha to which it was attached. These data suggest that the continued development of the haustorial mother cell requires some component normally provided by the host plant. Before they died, many haustorial mother cells apparently formed the thickened region of the wall which normally is traversed by the penetration peg during haustorium formation. Such a peg was observed in the centre of up to 40% of these thickened regions. However, no pegs protruded beyond the haustorial mother cell far enough to be called a haustorial neck. The thickened region of the haustorial mother cell wall could be differentiated from the rest of the wall by its lack of fluorescence under ultraviolet irradiation when mounted in Calcofluor or SITS (4-acetomido-4′-iso-thiocyanatostilbene-2,2′-disulphonic acid). Treatment with alkali, acid, chloroform–methanol, protease, and laminarinase did not affect this differential fluorescence, and the haustorial mother cell wall stained uniformly for proteins, carbohydrates, and chitin. Since Calcofluor normally binds to chitin, these data suggest that the thickened region of the haustorial mother cell wall may physically exclude the dye or may contain potential binding sites that are masked by other wall components.

Cytochemical studies on Puccinia graminis f. sp. tritici in a compatible wheat host. II. Haustorium mother cell walls at the host cell penetration site, haustorial walls, and the extrahaustorial matrix

1986 ◽  
Vol 64 (11) ◽  
pp. 2561-2575 ◽  
Author(s):  
J. Chong ◽  
D. E. Harder ◽  
R. Rohringer
Keyword(s):  
Host Cell ◽  
Mother Cell ◽  
Cell Walls ◽  
Distal Part ◽  
Rust Fungus ◽  
Neck Region ◽  
Cell Penetration ◽  
Wheat Stem Rust ◽  
Reactive Material ◽  
Extrahaustorial Matrix

Various cytochemical tests on the wheat stem rust fungus were used to determine differences in components of the walls of the haustorium mother cell at the host cell penetration site and the haustorial neck and body and to describe some of the chemical properties of the extrahaustorial matrix. There were two transition zones with respect to wall composition. The first was at the host cell penetration site; chitin, present in haustorium mother cell walls, was not detected in haustorial neck walls. The second transition zone was at the neck ring; compared with walls of the proximal neck region, those distal to the neck ring contained more protein and lost much of their periodate – thiocarbohydrazide – silver proteinate reactive material and all concanavalin A binding material after treatment with protease. The two wall layers of the distal part of the haustorial neck were continuous with those of the haustorium; the wall layers of young haustorial bodies shared their staining properties and lectin affinities with those of the distal part of the haustorial necks, reflecting their common origin. As the haustoria matured, their body walls bound wheat germ lectin, but the neck walls did not. Tests indicated that polysaccharide and glycoprotein were present in the extrahaustorial matrix.

Ultrastructure of the early stages of infection of peanut leaves by the rust fungus Puccinia arachidis

1989 ◽  
Vol 67 (12) ◽  
pp. 3570-3579 ◽  
Author(s):  
C. W. Mims ◽  
J. Taylor ◽  
E. A. Richardson
Keyword(s):  
Host Cell ◽  
Mother Cell ◽  
Primary Infection ◽  
Rust Fungus ◽  
Mitotic Division ◽  
Infection Process ◽  
Rust Disease ◽  
Puccinia Arachidis ◽  
Mother Cells ◽  
Infection Hypha

Peanut rust disease proved to be an excellent system for ultrastructural study of development of infection structures by the fungus Puccinia arachidis. Fungal structures were clearly visible by light microscopy in fixed and embedded samples and could be located either on leaf surfaces or within the large substomatal chambers of peanut leaves. Samples could easily be oriented for thin sectioning. The infection process was a highly orchestrated process involving precisely timed events and highly specialized structures. Infection pegs developed from appressoria over stomata and entered the leaf by growing into the openings between guard cells. Once past the rim formed by the guard cell walls, the infection peg expanded to form a substomatal vesicle in which a synchronous mitotic division of the four nuclei occurred. A primary infection hypha then developed from the vesicle and grew into the mesophyll of the leaf until its tip or side contacted a host cell. A septum then delimited a binucleate or trinucleate terminal haustorial mother cell from the remainder of the infection hypha. The wall of the haustorial mother cell became closely appressed to that of the host cell. Following differentiation of the haustorial mother cell, a penetration peg arose from it and penetrated the host cell wall. The peg invaginated the host cell plasma membrane as it elongated and then expanded at its tip to form the haustorium body into which most of the contents of the haustorial mother cell moved. Meanwhile, the primary infection hypha formed secondary hyphae that gave rise to additional haustorial mother cells and haustoria. Key words: Puccinia arachidis, peanut rust, infection process, ultrastructure.

Ultrastructural features of the haustorial apparatus of the white blister fungus Albugo candida

1975 ◽  
Vol 53 (13) ◽  
pp. 1285-1299 ◽  
Author(s):  
Michael D. Coffey
Keyword(s):  
Endoplasmic Reticulum ◽  
Cell Wall ◽  
Host Cell ◽  
Neck Region ◽  
Distal Portion ◽  
Thin Wall ◽  
Fungal Cell ◽  
White Blister ◽  
Host Cell Wall ◽  
Dark Staining

The small spherical haustorium of the white blister fungus is connected to the much larger haustorial mother cell by a slender cylindrical neck. The haustorium contains mitochondria with tubular cristae as well as ribosomes and occasional cisternae of rough endoplasmic reticulum. Nuclei and perinuclear dictyosomes are found in the mother cells but are absent from haustoria. No discontinuity is found in the fungal cell wall in the haustorial neck. Immediately adjacent to the fungal wall and extending through the penetration site to a point about midway along the neck is a dark-staining layer continuous with the host cell wall. A collar consisting of fibrillar material, also continuous with the host cell wall, is commonly found around the proximal portion of the neck external to this dark-staining layer. An electron-dense sheath surrounds the thin wall of the haustorial body but is absent from the neck region. A series of tubules is continuous with the invaginated host plasmalemma which surrounds the haustorial body. These tubules contain an electron-dense core similar in appearance to, and continuous with, the sheath matrix. No evidence was obtained for the involvement of host dictyosomes and their secretory vesicles in the formation of the haustorial sheath. A constant feature of the haustorial apparatus is the association of flattened cisternae of host endoplasmic reticulum with the distal portion of the haustorial neck. The significance of this finding is discussed in relation to the endomembrane concept.

scholarly journals Comparative Transcriptomic Analysis of Race 1 and Race 4 of Fusarium oxysporum f. sp. cubense Induced with Different Carbon Sources

2017 ◽  
Vol 7 (7) ◽  
pp. 2125-2138 ◽  
Author(s):  
Shiwen Qin ◽  
Chunyan Ji ◽  
Yunfeng Li ◽  
Zhenzhong Wang
Keyword(s):  
Gene Expression ◽  
Cell Wall ◽  
Fusarium Oxysporum ◽  
Host Cell ◽  
Expression Profiles ◽  
Cell Wall Polysaccharide ◽  
Host Cell Wall ◽  
Race 1 ◽  
Race 4 ◽  
Banana Cultivar

Abstract The fungal pathogen Fusarium oxysporum f. sp. cubense causes Fusarium wilt, one of the most destructive diseases in banana and plantain cultivars. Pathogenic race 1 attacks the “Gros Michel” banana cultivar, and race 4 is pathogenic to the Cavendish banana cultivar and those cultivars that are susceptible to Foc1. To understand the divergence in gene expression modules between the two races during degradation of the host cell wall, we performed RNA sequencing to compare the genome-wide transcriptional profiles of the two races grown in media containing banana cell wall, pectin, or glucose as the sole carbon source. Overall, the gene expression profiles of Foc1 and Foc4 in response to host cell wall or pectin appeared remarkably different. When grown with host cell wall, a much larger number of genes showed altered levels of expression in Foc4 in comparison with Foc1, including genes encoding carbohydrate-active enzymes (CAZymes) and other virulence-related genes. Additionally, the levels of gene expression were higher in Foc4 than in Foc1 when grown with host cell wall or pectin. Furthermore, a great majority of genes were differentially expressed in a variety-specific manner when induced by host cell wall or pectin. More specific CAZymes and other pathogenesis-related genes were expressed in Foc4 than in Foc1 when grown with host cell wall. The first transcriptome profiles obtained for Foc during degradation of the host cell wall may provide new insights into the mechanism of banana cell wall polysaccharide decomposition and the genetic basis of Foc host specificity.

scholarly journals Extracellular Polysaccharides from Xanthomonas axonopodis pv. manihotis Interact with Cassava Cell Walls During Pathogenesis

1997 ◽  
Vol 10 (7) ◽  
pp. 803-811 ◽  
Author(s):  
B. Boher ◽  
M. Nicole ◽  
M. Potin ◽  
J. P. Geiger
Keyword(s):  
Cell Wall ◽  
Monoclonal Antibodies ◽  
Host Cell ◽  
Cell Walls ◽  
Plant Cell Wall ◽  
Infection Process ◽  
Extracellular Polysaccharides ◽  
Xanthomonas Axonopodis ◽  
Cassava Leaves ◽  
Host Cell Wall

The location of lipopolysaccharides produced by Xanthomonas axonopodis pv. manihotis during pathogenesis on cassava (Manihot esculenta) was determined by fluorescence and electron microscopy immunolabeling with monoclonal antibodies. During the early stages of infection, pathogen lipopolysaccharides were detected on the outer surface of the bacterial envelope and in areas of the plant middle lamellae in the vicinity of the pathogen. Later in the infection process, lipopolysaccharide-specific antibodies bound to areas where the plant cell wall was heavily degraded. Lipopolysaccharides were not detected in the fibrillar matrix filling intercellular spaces of infected cassava leaves. Monoclonal antibodies specific for the exopolysaccharide xanthan side chain labeled the bacteria, the fibrillar matrix, and portions of the host cell wall. The association of Xanthomonas lipopolysaccharides with host cell walls during plant infection is consistent with a role of these bacterial extracellular polysaccharides in the infection process.

Ultrastructure of compatible and incompatible reactions of sunflower to Plasmopara halstedii

1979 ◽  
Vol 57 (4) ◽  
pp. 315-323 ◽  
Author(s):  
Glenn Wehtje ◽  
Larry J. Littlefield ◽  
David E. Zimmer
Keyword(s):  
Cell Wall ◽  
Plasma Membrane ◽  
Host Cell ◽  
Epidermal Cell ◽  
Cortical Cell ◽  
Hypersensitive Reaction ◽  
Host Cells ◽  
Plasmopara Halstedii ◽  
Host Cell Wall ◽  
Host Plasma Membrane

Penetration of sunflower, Heliantluis animus, root epidermal cells by zoospores of Plasmopara halstedii is preceded by formation of a papilla on the inner surface of the host cell wall that invaginates the host plasma membrane. Localized degradation and penetration of the host cell wall by the pathogen follow. The invading fungus forms an allantoid primary infection vesicle in the penetrated epidermal cell. The host plasma membrane invaginates around the infection vesicle but its continuity is difficult to follow. Upon exit from the epidermal cell the fungus may grow intercellularly, producing terminal haustorial branches which extend into adjacent host cells. The fungus may grow through one or two cortical cell is after growing from the epidermal cell before it becomes intercellular. Host plasma membrane is not penetrated by haustoria. Intercellular hyphae grow toward the apex of the plant and ramify the seedling tissue. Resistance in an immune cultivar is hypersensitive and is triggered upon contact of the host cell with the encysting zoospore before the host cell wall is penetrated. Degeneration of zoospore cytoplasm accompanies the hypersensitive reaction of the host. Zoospores were often parasitized by bacteria and did not germinate unless penicillin and streptomycin were added to the inoculum suspension.

scholarly journals Phylogenetic and comparative functional analysis of the cell-separation α-glucanase Agn1p in Schizosaccharomyces

Microbiology ◽  
2014 ◽  
Vol 160 (6) ◽  
pp. 1063-1074 ◽  
Author(s):  
Matthias Sipiczki ◽  
Anita Balazs ◽  
Aniko Monus ◽  
Laszlo Papp ◽  
Anna Horvath ◽  
...  
Keyword(s):  
Cell Wall ◽  
Schizosaccharomyces Pombe ◽  
Fission Yeast ◽  
Mother Cell ◽  
Cell Separation ◽  
Yeast Cells ◽  
Glycoside Hydrolase Family ◽  
Binding Domains ◽  
Yeast Phase ◽  
Mother Cell Wall

The post-cytokinetic separation of cells in cell-walled organisms involves enzymic processes that degrade a specific layer of the division septum and the region of the mother cell wall that edges the septum. In the fission yeast Schizosaccharomyces pombe, the 1,3-α-glucanase Agn1p, originally identified as a mutanase-like glycoside hydrolase family 71 (GH71) enzyme, dissolves the mother cell wall around the septum edge. Our search in the genomes of completely sequenced fungi identified GH71 hydrolases in Basidiomycota, Taphrinomycotina and Pezizomycotina, but not in Saccharomycotina. The most likely Agn1p orthologues in Pezizomycotina species are not mutanases having mutanase-binding domains, but experimentally non-characterized hypothetical proteins that have no carbohydrate-binding domains. The analysis of the GH71 domains corroborated the phylogenetic relationships of the Schizosaccharomyces species determined by previous studies, but suggested a closer relationship to the Basidiomycota proteins than to the Ascomycota proteins. In the Schizosaccharomyces genus, the Agn1p proteins are structurally conserved: their GH71 domains are flanked by N-terminal secretion signals and C-terminal sequences containing the conserved block YNFNAY/HTG. The inactivation of the agn1Sj gene in Schizosaccharomyces japonicus, the only true dimorphic member of the genus, caused a severe cell-separation defect in its yeast phase, but had no effect on the hyphal growth and yeast-to-mycelium transition. It did not affect the mycelium-to-yeast transition either, only delaying the separation of the yeast cells arising from the fragmenting hyphae. The heterologous expression of agn1Sj partially rescued the separation defect of the agn1Δ cells of Schizosaccharomyces pombe. The results presented indicate that the fission yeast Agn1p 1,3-α-glucanases of Schizosaccharomyces japonicus and Schizosaccharomyces pombe share conserved functions in the yeast phase.

scholarly journals Macromolecules released into the culture medium during the vegetative cell cycle of the unicellular green alga Chlamydomonas reinhardii

1985 ◽  
Vol 226 (1) ◽  
pp. 259-268 ◽  
Author(s):  
J Voigt
Keyword(s):  
Cell Cycle ◽  
Cell Wall ◽  
Cell Growth ◽  
Mother Cell ◽  
Culture Medium ◽  
Cell Enlargement ◽  
Chlamydomonas Reinhardii ◽  
Time Period ◽  
Protein Components ◽  
Mother Cell Wall

The culture medium of growing Chlamydomonas reinhardii cells contains hydroxyproline-rich glycoproteins, which are mainly liberated during release of the zoospores from the mother-cell wall. Pulse-labelling studies with [3H]proline and [35S]methionine have been performed in order to detect the protein components released by synchronously growing cells at different stages of the cell cycle. When either [3H]proline or [35S]methionine were applied during the phase of cell growth, radioactive label appeared in the released macromolecules after a lag period of 40 min, whereas incorporation into the insoluble part of the cell wall was delayed only by 20 min. When applied at the end of the growth phase, e.g. 13 h after beginning of the illumination period, the radioactive amino acids were incorporated into the cell wall, but radioactive labelling of macromolecules released into the culture medium could not be detected before the zoospores were liberated from the mother-cell wall. Maximal incorporation of [3H]proline and [35S]methionine into the insoluble part of the cell wall was observed during cell division, but essentially no radioactively-labelled macromolecules were released into the culture medium during this time period. Analysis of the macromolecules, which were liberated during cell enlargement, by sodium dodecyl sulphate/polyacrylamide-gel electrophoresis revealed distinct radioactive bands, which were differentially labelled with [3H]proline and [35S]methionine. Among the macromolecules released into the culture medium during cell growth, a component of an apparent Mr 35 000 was preferentially labelled with [3H]proline. This component was also detected after labelling with [35S]methionine, but components of an apparently higher Mr were more prominent after labelling with [35S]methionine. Macromolecules released during the cell-enlargement period of synchronously growing cultures in the presence of [3H]proline contained radioactively-labelled hydroxyproline in addition to proline. These results show that, during cell-wall growth, specific protein components are released into the culture medium and that at least one of these components contains large amounts of proline and hydroxyproline. At least some of these macromolecules seem to be constituents of the cell wall, because during pulse-chase experiments radioactively-labelled macromolecules appeared in the culture medium mainly during the time period when the specific radioactivity of the insoluble inner-cell-wall layer decreased.

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