The ultrastructure of Olpidium brassicae. III. Infection of host roots

1969 ◽  
Vol 47 (3) ◽  
pp. 421-424 ◽  
Author(s):  
J. H. M. Temmink ◽  
R. N. Campbell
Keyword(s):  
Cell Wall ◽  
Host Cell ◽  
Cyst Wall ◽  
Virus Transmission ◽  
Central Channel ◽  
Root Cells ◽  
Host Cytoplasm ◽  
Host Root ◽  
Host Cell Wall ◽  
Olpidium Brassicae

As zoospores of Olpidium brassicae (Wor.) Dang. encyst on host root cells, they retract their axoneme, secrete a cyst wall, and form an adhesive substance that keeps them in place. The axonemal fibrils have been observed within young cysts but disappear later. The host cell forms a papillum that seems to be an inward extension of the host cell wall. In the cyst, a vacuole develops and enlarges while the cyst protoplast moves through the host wall via a central channel in the papillum, penetrates the host ectoplast, and establishes itself within the host cytoplasm. The ectoplast present around the cyst protoplast remains in the cyst, along with parts of the tonoplast, after infection is complete. This information permits evaluation of hypotheses concerning virus transmission by zoospores.

Histopathology of Fusarium wilt of staghorn sumac (Rhus typhina) caused by Fusarium oxysporum f. sp. callistephi race 3. III. Host cell and tissue reactions

2006 ◽  
Vol 87 (1) ◽  
pp. 17-27 ◽  
Author(s):  
Guillemond B. Ouellette ◽  
Mohamed Cherif ◽  
Marie Simard
Keyword(s):  
Cell Wall ◽  
Fusarium Oxysporum ◽  
Host Cell ◽  
Cross Wall ◽  
Tissue Proliferation ◽  
Host Cytoplasm ◽  
Transmission Electron ◽  
Host Cell Wall ◽  
Tissue Reactions ◽  
Rhus Typhina

Abstract Various cell reactions occurred in staghorn sumac plants inoculated with Fusarium oxysporum f. sp. callistephi. Light and transmission electron microscopy observations and results of cytochemical tests showed: 1) increased laticifers and latex production in the phloem; 2) tylosis formation; 3) host cell wall modifications, including appositions or other cell wall thickenings; and 4) unusual cross wall formation in some cells, and cell hypertrophy and hyperplasia. Tylosis walls labelled for pectin and cellulose and many displayed inner suberin-like layers. These layers were also noted in cells of the medullary sheath and in many cells with dense content and thickened walls in the barrier zones that had formed. These zones also contained fibres with newly-formed gelatinous-like layers. In the vicinity of these cells, host cell walls were frequently altered, associated with opaque matter. Many small particles present in chains also occurred in some of these cells, which contained only remnants of host cytoplasm. Light microscopy observations showed that pronounced tissue proliferation and aberrant cells occurred in the outer xylem in the infected plants. Unusual neoplasmic tissue also formed from cells surrounding the pith and medullary sheath, and it spanned directly across the pre-existing xylem tissue and burst as large mounds on the stems.

Host–parasite relations in mycoparasite. I. Fine structure of host, parasite, and their interface

1971 ◽  
Vol 49 (9) ◽  
pp. 1677-1681 ◽  
Author(s):  
M. S. Manocha ◽  
K. Y. Lee
Keyword(s):  
Cell Wall ◽  
Fine Structure ◽  
Host Cell ◽  
Higher Plants ◽  
Host Cytoplasm ◽  
Host Cell Wall ◽  
Choanephora Cucurbitarum ◽  
A Cell ◽  
Host Parasite

A mycoparasite, Piptocephalis virginiana, shows resemblance to other fungal parasites of higher plants in the fine structure of hyphae and haustoria. The mode of penetration of the host cell, Choanephora cucurbitarum, probably involves mechanical forces. Although the presence of a cell wall degrading enzyme was not detected by conventional techniques, its role in penetration can not be ruled out. A collar around the haustorial neck is formed as an extension of the host cell wall. No papilla was detected although appressorium was seen during penetration. The young haustorium is enclosed in highly invaginating plasmalemma of the host cell and numerous cisternae of endoplasmic reticulum (ER). Appearance of an electron-dense sheath around the mature haustorium seems to coincide with the disappearance of cisternae of ER from the host cytoplasm in the vicinity of the haustorium. The role of host cytoplasm, particularly of ER, in the development of the sheath is discussed. Extensive accumulation of spherosome-like bodies, containing lipids, is found in haustorium, parasite, and host hypha.

A fine-structural study of the pea downy mildew fungus Peronospora pisi in its host Pisum sativum

1977 ◽  
Vol 55 (23) ◽  
pp. 2845-2858 ◽  
Author(s):  
Edward L. Hickey ◽  
Michael D. Coffey
Keyword(s):  
Cell Wall ◽  
Pisum Sativum ◽  
Host Cell ◽  
Downy Mildew ◽  
Specific Interaction ◽  
Young Shoot ◽  
Host Cytoplasm ◽  
Shoot Tissue ◽  
Host Cell Wall ◽  
Membrane Bound

Downy mildew disease of the cultivated pea Pisum sativum L. caused by the fungus Peronospora pisi Sydow was studied in mature leaves and young shoots of the host plant. Particularly in systemic infections of young shoot tissue, a common occurrence was an extremely electron-opaque membrane-bound, hemispherical deposit extending through the host cell wall into the host cytoplasm. This material which abutted directly onto the intercellular hyphal wall was termed the penetration matrix. Its formation was apparently the result of a specific interaction between the host and obligate fungal parasite. Similar apparently solid or gellike material constituted the matrix surrounding the digitlike intracellular haustorium. This membrane-bound extrahaustorial matrix was present through the penetrated host cell wall and formed a relatively thick layer around haustoria in young shoot tissue, but was much thinner distally around haustoria in mature leaf mesophyll cells. An unusual, regularly arranged, tubular network of ribosome-free endoplasmic reticulum was occasionally found in the host cytoplasm in systemically infected shoot tissue adjacent to haustoria.

Haustorial development of Peronospora tabacina infecting Nicotiana tabacum

1983 ◽  
Vol 61 (12) ◽  
pp. 3444-3453 ◽  
Author(s):  
R. N. Trigiano ◽  
C. G. Van Dyke ◽  
H. W. Spurr Jr.
Keyword(s):  
Cell Wall ◽  
Toluidine Blue ◽  
Mesophyll Cell ◽  
Wall Layer ◽  
Peronospora Tabacina ◽  
Host Cytoplasm ◽  
Transmission Electron ◽  
Mold Fungus ◽  
Host Cell Wall ◽  
Hyphal Wall

The development of haustoria in tobacco by the blue-mold fungus Peronospora tabacina was examined using light, scanning, and transmission electron microscopy. Electron-lucent, callose-like appositions were observed between the host plasmalemma and the host mesophyll cell wall prior to haustorial penetration. An electron-opaque penetration matrix was present between the apposition and the host cell wall. The intercellular hyphal wall consisted of two layers which differed in staining quality. The haustorial wall was also two layered, but was primarily composed of and continuous with the inner wall layer of the intercellular hypha. Haustoria were either finger-like or branched and were encased with callose-like material. Most encasements were thickened at the proximal regions of haustoria but were thinner along the distal portions. Vesicles were present in host cytoplasm and were occasionally attached to the invaginated host plasmalemma. These vesicles might contribute to the deposition of the encasement material. The encasement stained positively for callose using aniline blue; calcofluor and toluidine blue O tests for cellulose were inconclusive, and lignin was not detected using toluidine blue O or phloroglucinol–HCl.

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.

Host cell wall synthesis and its role in resistance to a mycoparasite

1982 ◽  
Vol 20 (2) ◽  
pp. 157-164 ◽  
Author(s):  
M.S. Manocha ◽  
Lori L. Graham
Keyword(s):  
Cell Wall ◽  
Host Cell ◽  
Cell Wall Synthesis ◽  
Host Cell Wall

scholarly journals Lactococcal Bacteriophages Require a Host Cell Wall Carbohydrate and a Plasma Membrane Protein for Adsorption and Ejection of DNA

1994 ◽  
Vol 60 (9) ◽  
pp. 3204-3211 ◽  
Author(s):  
Marshall R. Monteville ◽  
Bahram Ardestani ◽  
Bruce L. Geller
Keyword(s):  
Cell Wall ◽  
Plasma Membrane ◽  
Membrane Protein ◽  
Host Cell ◽  
Plasma Membrane Protein ◽  
Host Cell Wall
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