Characterization of the interaction between the dark septate fungus Phialocephala fortinii and Asparagus officinalis roots

2001 ◽  
Vol 47 (8) ◽  
pp. 741-753 ◽  
Author(s):  
T Yu ◽  
A Nassuth ◽  
R L Peterson
Keyword(s):  
Root Hairs ◽  
Root Surface ◽  
Epidermal Cells ◽  
Asparagus Officinalis ◽  
Structural Basis ◽  
Root Penetration ◽  
Root Tips ◽  
Cortical Cells ◽  
Phialocephala Fortinii

Phialocephala fortinii Wang & Wilcox is a member of root-inhabiting fungi known collectively as dark septate endophytes (DSE). Although very common and distributed worldwide, few studies have documented their interaction with roots on a structural basis. The objective of this study was to determine the early colonization events and formation of microsclerotia of P. fortinii in roots of Asparagus officinalis L., a species known to have DSE. A loose network of hyphae accumulated at the root surface, and coils formed around root hairs and external to epidermal cells overlying short cells of the dimorphic, suberized exodermis. Root penetration occurred via swollen, appressorium-like structures into epidermal cells where coiling of hyphae occurred along the periphery of the cells. Hyphae penetrated from the epidermis into short exodermal cells and from these into cortical cells. Hyphae colonized the cortex up to the endodermis and sometimes entered the vascular cylinder. Some root tips were colonized as well. Microsclerotia in epidermal and exodermal short cells accumulated glycogen, protein, and polyphosphate. Energy-dispersive X-ray spectroscopy on distinct bodies visible in microsclerotial hyphae revealed high levels of phosphorus.Key words: Mycelium radicis atrovirens, Phialocephala fortinii, microsclerotia, DSE.

Structure and ontogeny of Betula alleghaniensis – Pisolithus tinctorius ectomycorrhizae

1990 ◽  
Vol 68 (3) ◽  
pp. 579-593 ◽  
Author(s):  
H. B. Massicotte ◽  
R. L. Peterson ◽  
C. A. Ackerley ◽  
L. H. Melville
Keyword(s):  
Root Hairs ◽  
Root Surface ◽  
Pisolithus Tinctorius ◽  
Initial Contact ◽  
Broad Host Range ◽  
Betula Alleghaniensis ◽  
Cortical Cells ◽  
Structural Modifications ◽  
Hartig Net ◽  
Primary Roots

The ontogeny and ultrastructure of ectomycorrhizae synthesized between Betula alleghaniensis (yellow birch) and Pisolithus tinctorius, a broad host range fungus, were studied to determine the structural modifications in both symbionts during ectomycorrhiza establishment. A number of stages, including initial contact of hyphae with the root surface, early mantle formation, and mature mantle formation, were distinguished. Interactions between hyphae and root hairs were frequent. As a paraepidermal Hartig net developed, root epidermal cells elongated in a radial direction, but wall ingrowths were not formed. Repeated branching of Hartig net hyphae resulted in extensive fine branches and the compartmentalization of hyphal cytoplasm. Nuclei and elongated mitochondria were frequently located in the narrow cytoplasmic compartments, and [Formula: see text] thickenings developed along walls of cortical cells in primary roots.

scholarly journals Seed-transmitted beneficial endophytic Stagonospora sp. can penetrate the walls of the root epidermis, but does not proliferate in the cortex, of Phragmites australis

2006 ◽  
Vol 84 (6) ◽  
pp. 981-988 ◽  
Author(s):  
Kexiang Gao ◽  
Kurt Mendgen
Keyword(s):  
Phragmites Australis ◽  
Endophytic Fungus ◽  
Hyphal Growth ◽  
Root Surface ◽  
Cortical Layer ◽  
Epidermal Cells ◽  
Cortical Cells ◽  
Root Epidermis ◽  
Wall Appositions

Stagonospora sp. (4/99-1) is a beneficial endophytic fungus frequently transmitted by seeds of Phragmites australis [Cav.] Trin. ex Steudel. Here we show that this fungus also penetrates the root epidermis. At first, hyphae were attracted by the root and proliferated on the root surface, preferably over the anticlinal walls. Penetration occurred directly by undifferentiated hyphae or was facilitated by hyphopodia. Hyphal growth within the root was restricted to the walls of epidermal cells and the walls of the cells of the outermost cortical layer. Deeper growth by the fungus elicited wall appositions and ingress into the cytoplasm of cortical cells was blocked by papillae. In the rare cases, the fungus managed to penetrate into cortical cells, these reacted with necrosis. Immunological studies suggested that fungal material reached the host plasmalemma and may have been taken up by endocytotic events. Our observations explain the endophytic lifestyle of hyphae close to the epidermis and the restricted development within the cortex.

Histopathology of Pythium infected strawberry roots

1972 ◽  
Vol 50 (5) ◽  
pp. 1091-1096 ◽  
Author(s):  
S. Nemec
Keyword(s):  
Root Hairs ◽  
Petri Dish ◽  
Root Tip ◽  
Test Results ◽  
Root Tips ◽  
Cortical Cells ◽  
Pythium Irregulare ◽  
Infected Root ◽  
Cortical Infection ◽  
Host Parasite

Host–parasite interactions between eight Pythium species, previously isolated from necrotic strawberry root tissue, and Fragaria × ananassa Duch. runner plant main roots were studied. When excised roots were placed in water on petri dish cultures, P. rostratum and P. hypogenum infection was limited to the root tip epidermis. Pythium irregulare, P. perniciosum, P. dissotocum, P. sylvaticum, P. ultimum, and unidentified isolate 1E penetrated the epidermis several centimeters along the zone of maturation. Penetration occurred most frequently through root hairs by hyphae; resulting infections usually stopped in the epidermis or adjacent cortex, and here hyphae formed sporangium-like structures, oogonia, and oospores. Extensive cortical infection by hyphae was primarily limited to the zone of elongation. Extent of epidermal and cortical infection in roots grown in soil with P. irregulare, P. dissotocum, and P. sylvaticum was similar to petri dish test results. Stelar infection by P. sylvaticum and P. dissotocum occurred mainly in phloem cells, but did not advance far into the region of maturation. Numerous oogonia formed in infected steles and usually in adjacent cortical cells. Infected roots ranged from a white to grey, water-soaked color. Extensively infected root tips typically were unhealthy, succulent, and thin.

Chemical and Physical Modification of the Rhizosphere

2000 ◽  
Author(s):  
Peter B. Tinker ◽  
Peter Nye
Keyword(s):  
Root Hairs ◽  
Soil Surface ◽  
Fine Sand ◽  
Root Surface ◽  
Root Penetration ◽  
Wheat Roots ◽  
Order Of Magnitude ◽  
Seminal Roots ◽  
Dry Soil ◽  
Living Organisms

The term ‘rhizosphere’ tends to mean different things to different people. In discussing how a root affects the soil, it is well to bear in mind the spread of the zone being exploited for a particular solute: if this is wide, there may be no point in emphasizing effects close to the root; but if it is narrow, predictions based on the behaviour of the bulk soil may be wide of the mark. In a moist loam after 10 days, a simple non-adsorbed solute moves about 1 cm, but a strongly adsorbed one will move about 1 mm. In a dry soil, the spread may be an order of magnitude less. The modifications to the soil in the rhizosphere may be physical, chemical or microbiological. In this chapter, we discuss essentially non-living modifications, and in chapter 8 the modifications that involve living organisms and their effects. Roots tend to follow pores and channels that are not much less, and are often larger, in diameter than their own. If the channels are larger, the roots are not randomly arranged in the void (Kooistra et al. 1992), but tend to be held against a soil surface by surface tension, and to follow the channel geotropically on the down-side. If the channels are smaller, good contact is assured, but the roots do not grow freely unless some soil is displaced as the root advances. For example, in winter wheat, Low (1972) cites minimum pore sizes of 390–450 μm for primary seminal roots, 320–370 μm for primary laterals, 300–350 μm for secondary laterals, and 8–12 μm for root hairs, though some figures seem large. Whiteley & Dexter (1984) and Dexter (1986a, b, c) have studied the mechanics of root penetration in detail (section 9.3.5). It may compact and reorient the soil at the root surface. Greacen et al. (1968) found that wheat roots penetrating a uniform fine sand increased the density only from 1.4 to 1.5 close to the root; and a pea radicle, a comparatively large root, raised the density of a loam from 1.5 to 1.55.

Root-hair structure and development in the seagrass Halophila ovalis (R. Br.) Hook. F

1993 ◽  
Vol 44 (1) ◽  
pp. 85 ◽  
Author(s):  
DG Roberts
Keyword(s):  
Endoplasmic Reticulum ◽  
Nutrient Uptake ◽  
Root Hair ◽  
Root Hairs ◽  
Active Role ◽  
Root Surface ◽  
Cortical Cells ◽  
Golgi Bodies ◽  
Halophila Ovalis ◽  
Active Root

The seagrass Halophila ovalis normally produces one mature root, covered with a permanent mat of root hairs, per node. In this study, the development of the root hairs increased the effective root surface absorptive area by 215%. Of the root surface examined, 39% was devoted to root-hair production. Epidermal cells that produced root hairs contained more cytoplasm, endoplasmic reticulum and Golgi bodies than did adjacent hairless cells. In addition to appearing to be more metabolically active, root-hair-producing cells had a greater number of plasmodesmatal connections with the underlying outer cortical cells than did adjacent cells that did not produce root hairs. This would suggest that cells that produce root hairs play a more active role in nutrient uptake and exchange than do other cortical cells.

scholarly journals Morpho-anatomical characterization of Rhizopogon himalayensis - Cedrus deodara mycorrhiza

2021 ◽  
Vol 13 (2) ◽  
pp. 668-676
Author(s):  
Gunjan Thakur ◽  
K. S. Kapoor ◽  
Ashwani Tapwal
Keyword(s):  
Root Surface ◽  
Symbiotic Association ◽  
Root Tips ◽  
Cortical Cells ◽  
Cedrus Deodara ◽  
Anatomical Characteristics ◽  
Specific Objective ◽  
Mycorrhizal Association ◽  
Depth Analysis ◽  
First Time

Rhizopogon himalayensis (Castellano, S.L. Miller, Singh & Lakhanpal) A.B. Mujic & M.E. Sm., comb. nov. -an edible truffle-like fungus- normally exists in a symbiotic association with Cedrus deodara (Roxb.) Loud. Because of this important association and the ecological significance as per the available literature attached to this fungus, the present study was undertaken with a specific objective to test the mycorrhizal viability of this mycobiont with this important tree species of Himalaya -the theme tree of Himachal Pradesh. An attempt to investigate and record morphological and anatomical characteristics and variations in this mycorrhizal association was also made in nursery conditions using pure culture (wheat grain spawn) of R. himalayensis. The seedlings grown and inoculated in the nursery were harvested after six months for further examination, including the microscopic details. The study and subsequent analysis revealed that that mycobiont had invaded most of the feeder roots, imparting a typical swollen appearance to the mycorrhizal root tips. These root tips were light ochre with moderately thick plectenchymatic fungal mantle with occasional clamp connections on the inner layer of the fungal mantle. The root surface, as seen, was found smooth and frequently covered with a loose aggregation of inter-woven hyphae that uniformly pervaded the epidermis extending into the inter-cortical spaces of outer cortical cells and formed a characteristic Hartig net. Thus, results obtained in fact for the first time, presented an in-depth analysis of the morphological and anatomical characteristics of R. himalayensis and C. deodara association. 

Chemotaxis of zoospores of Phytophthora megasperma to primary roots of alfalfa seedlings

1978 ◽  
Vol 56 (7) ◽  
pp. 795-800 ◽  
Author(s):  
C. C. Chi ◽  
F. E. Sabo
Keyword(s):  
Trifolium Pratense ◽  
Primary Root ◽  
Root Hairs ◽  
Red Clover ◽  
Root Surface ◽  
Root Cap ◽  
Root Tips ◽  
Phytophthora Megasperma ◽  
Root Area ◽  
Primary Roots

Chemotaxis of the zoospores of Phytophthora megasperma was studied on freshly excised primary root tips of 2-day-old seedlings of nine alfalfa (Medicago sativa L.) cultivars and four other legume species. The highly susceptible cultivars Saranac, Algonquin, and Vernal attracted masses of zoospores within minutes after being placed into fresh zoospore suspensions. The moderately susceptible cultivars Iroquois, Angus, and Thor displayed less severe en masse zoospore accumulation. Resistant cultivars Apollo, Agate, and to a lesser degree WL-318 exhibited minor chemotaxis.Zoospores were strongly attracted to the region of elongation, immediately above the root cap area. Relatively few zoospores, if any, were attracted to the root cap and older regions of the roots. Zoospores were not attracted to root hairs. Within 0.5-1 h, zoospores attracted to the roots began to encyst and germinate. Germ tubes always originated from the side of cysts closest to the root surface, and all showed unidirectional growth towards the root.Very weak or no chemotactic responses of zoospores to nonhost legume plants of white sweet clover (Melilotus alba Desr.), red clover (Trifolium pratense L.), bird's-foot trefoil (Lotus corniculatus L.), and soybean (Glycine max (L.) Merr. cv. Vansoy) were observed. Roots of susceptible alfalfa seedlings pretreated in boiling water did not attract zoospores.Injured, susceptible alfalfa roots displayed a strong preferential attraction around a wounded root area. Varying zoospore densities occurred at different distances from the wound. Wounded, resistant alfalfa roots showed slightly more zoospore accumulation than the uninjured resistant roots.The magnitude of chemotaxis and response time appear to be related to the susceptibility or resistance of the young, primary roots of alfalfa seedlings.

Ectomycorrhizal and ectendomycorrhizal associations of Phialophorafinlandia with Pinusresinosa, Picearubens, and Betulaalleghaniensis

1987 ◽  
Vol 17 (8) ◽  
pp. 976-990 ◽  
Author(s):  
H. E. Wilcox ◽  
C. J. K. Wang
Keyword(s):  
Large Diameter ◽  
Root Surface ◽  
Epidermal Cells ◽  
Cortical Cells ◽  
Hartig Net ◽  
Mycorrhizal Associations ◽  
Intracellular Invasion ◽  
Inner Cortex ◽  
Root Axis ◽  
Distributed Clusters

Mycorrhizal associations formed by Phialophorafinlandia in Pinusresinosa were both ectomycorrhizal and ectendomycorrhizal with randomly distributed clusters of spherical hyphae within cells of the cortex. The ectomycorrhizal condition was common for short distances in the apices of short roots and in smaller diameter long roots, but intracellular invasion from the Hartig net occurred proximal to this zone, resulting in an ectendomycorrhizal structure. In large diameter long-root branches both conditions were found at different positions along the root axis. In addition, sclerotia-like inclusions occurred in the inner cortical cells, often radially opposite to the protoxylem. Mycorrhizal associations in Picearubens and Betulaalleghaniensis were predominantly ectomycorrhizal in all roots; sclerotial bodies could be present in the inner cortex of both hosts. The Hartig net extended to the endodermis in the spruce, but it surrounded only the epidermis in birch. The epidermal cells of birch ectendomycorrhizae elongated radially and obliquely to the root surface, but in spruce the mycorrhizal condition had no effect on radial dimensions of cortical cells.

Characterization of the interaction between the dark septate fungus Phialocephala fortinii and Asparagus officinalis roots

2001 ◽  
Vol 47 (8) ◽  
pp. 741-753 ◽  
Author(s):  
T. Yu ◽  
A. Nassuth ◽  
R.L. Peterson
Keyword(s):  
Asparagus Officinalis ◽  
Phialocephala Fortinii

Endophytic fungi from the mycorrhizae of alpine ericoid plants

1991 ◽  
Vol 69 (2) ◽  
pp. 347-352 ◽  
Author(s):  
Godo Stoyke ◽  
R. S. Currah
Keyword(s):  
Key Words ◽  
Endophytic Fungi ◽  
Rocky Mountains ◽  
Root Surface ◽  
Root Cells ◽  
Phialocephala Fortinii ◽  
Axenic Cultures ◽  
Slow Growing ◽  
Key Words Alpine

Strains of a slow-growing, sterile, darkly pigmented fungus were obtained from alpine mycorrhizae of the Alberta Rocky Mountains. Sporulating isolates of this fungus from the roots of Cassiope mertensiana and Arctostaphylos uva-ursi (Ericaceae) as well as from Luetkea pectinata (Rosaceae) were identified as Phialocephala fortinii. Axenic cultures of Menziesia ferruginea (Ericaceae) seedlings were grown with P. fortinii for characterization of the fungus–root association. Typically, dark, simple septate hyphae form extensive wefts on the root surface and produce intracortical sclerotia of compact, darkly pigmented and irregularly lobed, thick-walled hyphae. Intracellular coils are not produced. This association differs from the ericoid mycorrhizal type and represents a fungus–root association that is common in alpine plants. In addition, several isolates of Oidiodendron griseum, a species previously reported from mycorrhizae of ericaceous plants, were found to form intracellular coils within the cortical root cells of Loiseleuria procumbens (Ericaceae). Key words: alpine mycorrhizae, Ericaceae, Phialocephala fortinii, Oidiodendron griseum.

Sign in / Sign up

Export Citation Format

Share Document