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.

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.

Suppression of host cell wall synthesis at penetration sites in a compatible interaction with a mycoparasite

1985 ◽  
Vol 63 (5) ◽  
pp. 967-973 ◽  
Author(s):  
M. S. Manocha ◽  
C. M. McCullough
Keyword(s):  
Cell Wall ◽  
Host Cell ◽  
Chitin Synthase ◽  
Compatible Interaction ◽  
Cell Wall Synthesis ◽  
Susceptible Host ◽  
Label Incorporation ◽  
Host Cell Wall ◽  
Choanephora Cucurbitarum

Differences in cell wall reactions at the penetration sites on a resistant host, Phascolomyces articulosus Boedijn ex Benny and Benjamin, and on a susceptible host, Choanephora cucurbitarum (Berk. & Rav.) Thaxter, were studied by autoradiography at 18 h after inoculation with a mycoparasite, Piptocephalis virginiana Leadbeater and Mercer. Localized incorporation of a radioactive chitin precursor, N-[3H]acetylglucosamine ([3H]GlcNAc), was observed at the penetration sites on the resistant but not the susceptible host. Autoradiography of mechanically wounded hyphae of the susceptible and resistant hosts showed similar patterns of localized incorporation of [3H]GlcNAc within 5 min after sonication. Label incorporation at the penetration as well as at the wounding sites was inhibited by polyoxin D. Cycloheximide treatment greatly increased the label in subapical regions and reduced that at the hyphal tips in both the hosts, whereas this treatment did not prevent localized incorporation at the wounding or the penetration sites on the resistant host. Suppression of localized incorporation of [3H]GlcNAc at penetration sites in C. cucurbitarum was not due to the lack of mobility of chitin synthase to the penetration site or its activating factor.

Ultrastructure of the host–parasite interface in the fern rusts Milesia, Uredinopsis, and Hyalopsora (Pucciniastraceae, Uredinales)

1994 ◽  
Vol 72 (8) ◽  
pp. 1084-1094 ◽  
Author(s):  
R. Berndt ◽  
R. Bauer ◽  
F. Oberwinkler
Keyword(s):  
Cell Wall ◽  
Key Words ◽  
Host Cell ◽  
Electron Density ◽  
Host Cell Wall ◽  
Host Parasite ◽  
Extrahaustorial Matrix

Species of the genera Milesia, Uredinopsis, and Hyalopsora possessed D-haustoria the necks of which were sheathed by an extension of the extrahaustorial matrix. Haustoria of the investigated species of Milesia and Uredinopsis were botryose with a haustorial body that formed wormlike protuberances. The Hyalopsora spp. were characterized by a vesicular haustorium. In the species of Milesia and associated Uredo spp. the haustorial neck was frequently differentiated into areas of variable electron density and structure; in Milesia blechni, Milesia miyabei, and Uredo RB 2537 a second neckband was formed in many haustoria. The penetration channels were usually characterized by short, perpendicularly oriented fibrillar elements that extended into the surrounding host cell wall. The haustoria of Uredinopsis filicina, Hyalopsora polypodii, and Hyalopsora aspidiotus were different from those of the investigated species of Milesia and Uredo. Their necks were accompanied by short extensions of the extrahaustorial matrix and the neck walls stained more or less homogeneously proximal to the neckband. Key words: Milesia, Uredinopsis, Hyalopsora, D-haustoria, ultrastructure, systematics.

Host – parasite relationships between the fungus Leptosphaerulina crassiasca and peanut

1992 ◽  
Vol 70 (9) ◽  
pp. 1724-1733 ◽  
Author(s):  
Mei-Lee Wu ◽  
Richard T. Hanlin
Keyword(s):  
Cell Wall ◽  
Host Cell ◽  
Germ Tube ◽  
Light And Electron Microscopy ◽  
Host Cells ◽  
Detached Leaves ◽  
Host Cell Wall ◽  
Host Parasite ◽  
Germ Tubes ◽  
Infection Hypha

The mode of penetration and infection of the peanut leaf by Leptosphaerulina crassiasca were studied by means of light and electron microscopy. The attachment of the multicellular ascospores to the leaf surface was by a mucilagenous sheath that covered the ascospores at maturity. This sheath expanded rapidly in moisture and it extended along the germ tube as it elongated. Two types of germ tubes appeared to be formed, a short one and a relatively long one. Short germ tubes were not delimited by septa, and they penetrated the cuticle and host epidermal cell wall directly without appressorium formation. Penetration occurred 2–6 h after inoculation. The wall was breached by a relatively broad infection hypha that expanded in width inside the host cell wall. The lack of mechanical rupture at the infection site indicated that penetration may involve enzymatic activity. Intracellular hyphae were present in the epidermal cells, but only intercellular hyphae occurred in the palisade and spongy mesophyll tissues. The intercellular hyphae were frequently appressed to the outer surface of the host cell wall. Infected areas rarely exceeded 1 mm in diameter, and they were only sparsely colonized by hyphae of the pathogen. Host cells in the vicinity of hyphae underwent senescence and death. One to 2 months after inoculation, pseudothecia formed in the dead tissues of detached leaves. In some instances the presence of penetration hyphae by short germ tubes induced the formation of a papilla inside the host cell wall, which either restricted growth of the infection hypha or resulted in the death of the germ tube and the cell from which it arose. Long germ tubes were delimited by simple septa and they terminated in an appressorium; however, details of their behavior were not studied. Key words: Arachis hypogaea, Ascomycotina, Dothideales, leaf scorch, pepper spot.

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.

The Alternaria brassicae – Nectria inventa host–parasite interface

1977 ◽  
Vol 55 (4) ◽  
pp. 448-454 ◽  
Author(s):  
A. Tsuneda ◽  
W. P. Skoropad
Keyword(s):  
Cell Wall ◽  
Host Cell ◽  
Host Cells ◽  
Alternaria Brassicae ◽  
Adhesive Material ◽  
Large Hole ◽  
Mature Conidium ◽  
Host Cell Wall ◽  
Host Parasite

The Verticillium state of Nectria inventa is a destructive parasite of Alternaria brassicae. Tropic growth of parasite hyphae towards hyphae and conidia of A. brassicae occurs in the vicinity of the host. Upon contact, the parasite hyphae often form appressorium-like bodies on the host cells and produce fibrous adhesive material at the host–parasite interface. Conidia are penetrated more commonly than hyphae. Penetration of the septa in hyphae results in a separation of cells. Penetration of a mature conidium also occurs commonly at a septum. The presence of a large hole in the wall of the host cell and the meshwork of material at the penetration site suggest that enzymatic breakdown of host cell wall occurs. Juvenile conidia are penetrated usually at the basal pore.

Studies of the Penetration of Bdellovibrio into Host Cells

1971 ◽  
Vol 29 ◽  
pp. 336-337
Author(s):  
Dinah Abram ◽  
David Chou
Keyword(s):  
Electron Microscopy ◽  
Escherichia Coli ◽  
Cell Wall ◽  
Pseudomonas Fluorescens ◽  
Host Cell ◽  
Host Cells ◽  
Sequence Of Events ◽  
Host Cell Wall ◽  
Host Parasite ◽  
Infectious Cycle

The sequence of events in the infectious cycle of the endoparasite Bdello-vibrio bacteriovorus, from its attachment to the host surface to the release of progeny from lysed host are well established. However, the mechanisms involved in the parasite entry through a pore in the host cell wall into its periplasm have been topics for speculations but are not fully understood.Escherichia coli, Pseudomonas fluorescens and Spirillum serpens were infected by several Bdellovibrio strains (109, D and 6-5-S) in mixtures containing 109 to 1010 host cells/ml and host-parasite in ratios of 1:2 to 1:3, and were incubated at 30 C with shaking for 4 hr. At intervals specimens were prepared for electron microscopy and wet mounts were examined by phase optics.

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.

Etude cinétique, en microscopie électronique, des interactions entre Colletotrichum lagenarium et les cellules foliaires de Cucumis melo

1974 ◽  
Vol 52 (6) ◽  
pp. 1319-1323 ◽  
Author(s):  
Robert Dargent ◽  
André Touzé
Keyword(s):  
Cell Wall ◽  
Fine Structure ◽  
Host Cell ◽  
Cucumis Melo ◽  
Intracellular Localization ◽  
Cell Degeneration ◽  
Microscopie Électronique ◽  
Host Cell Wall ◽  
Hyphal Apex ◽  
Apparently Healthy

The ultrastructure of apparently healthy mesophyllic cells of muskmelon seedlings is briefly described.Electron micrographs of invaded cells 72 h after inoculation show the intracellular localization of the pathogen and the alteration of the host cell wall in contact with the hyphal apex, the capsulation of hyphae by the host-cell plasmalemma, and the swelling of chloroplasts, nuclei, and mitochondria.When symptoms appear, about 96 h after inoculation, electron micrographs show advanced host cell degeneration, and the fine structure of invading hyphae, including septa formation.

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.

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