Structure and ontogeny of Alnus crispa – Alpova diplophloeus ectomycorrhizae

1986 ◽  
Vol 64 (1) ◽  
pp. 177-192 ◽  
Author(s):  
H. B. Massicotte ◽  
R. L. Peterson ◽  
C. A. Ackerley ◽  
Y. Piché
Keyword(s):  
Structural Changes ◽  
Hyphal Growth ◽  
Root Surface ◽  
Epidermal Cells ◽  
Transfer Cells ◽  
Wall Ingrowths ◽  
Alnus Crispa ◽  
Hartig Net ◽  
Fungal Hyphae ◽  
Branching System

Alnus crispa (Ait.) Pursh seedlings were grown in plastic pouches and inoculated with Frankia to induce nodules and subsequently with Alpova diplophloeus (Zeller & Dodge) Trappe & Smith to form ectomycorrhizae. The earliest events in ectomycorrhiza formation involved contact of the root surface by hyphae, hyphal proliferation to form a thin mantle, and further hyphal growth to form a thick mantle. Structural changes in the host, the mycosymbiont, and the fungus–epidermis interface were described at various stages in the ontogeny of ectomycorrhizae. Fungal hyphae in contact with epidermal cells in the regions of intercellular penetration and paraepidermal Hartig net developed numerous rough endoplastic reticulum cisternae. In more proximal regions of the mycorrhiza, these gradually became fewer in number and smooth. A complicated labyrinthine wall branching system also developed in the fungus in these regions. Concurrently, epidermal cells formed wall ingrowths in regions adjacent to Hartig net hyphae. There was a gradient in the formation of these epidermal transfer cells as the mycorrhiza developed, and an additional deposition of secondary cell wall over the wall ingrowths occurred as transfer cells senesced. Nonmycorrhizal control roots did not develop epidermal wall ingrowths. Electron-dense material, which was also autofluorescent, was deposited in the outer tangential walls of the exodermis contiguous to the paraepidermal Hartig net.

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.

Ontogeny of Alnus rubra – Alpova diplophloeus ectomycorrhizae. II. Transmission electron microscopy

1989 ◽  
Vol 67 (1) ◽  
pp. 201-210 ◽  
Author(s):  
H. B. Massicotte ◽  
C. A. Ackerley ◽  
R. L. Peterson
Keyword(s):  
Electron Microscopy ◽  
Epidermal Cells ◽  
Root Cap ◽  
Alnus Rubra ◽  
Golgi Bodies ◽  
Hartig Net ◽  
Transmission Electron ◽  
Meristem Zone ◽  
Basal Portion ◽  
Branching System

Ultrastructural features of the two symbionts in ectomycorrhizae formed between Alnus rubra and Alpova diplophloeus change with developmental stage. In the root cap – meristem zone, hyphae penetrate between vacuolated root cap cells and become appressed to epidermal cells containing small vacuoles, plastids with starch, numerous Golgi bodies, mitochondria, and endoplasmic reticulum cisternae. In the young Hartig net zone, hyphae with few vacuoles penetrate between vacuolated epidermal cells that still contain numerous Golgi bodies but now have plastids with small starch grains. Hartig net hyphae begin to branch and eventually form a complex branching system in the mature Hartig net zone. Hartig net hyphae in the basal portion of the ectomycorrhizae synthesize lipid and finally become vacuolated.

The root–fungus interface as an indicator of symbiont interaction in ectomycorrhizae

1987 ◽  
Vol 17 (8) ◽  
pp. 846-854 ◽  
Author(s):  
H. B. Massicotte ◽  
C. A. Ackerley ◽  
R. L. Peterson
Keyword(s):  
Cell Wall ◽  
Epidermal Cell ◽  
Apical Meristem ◽  
Epidermal Cells ◽  
Wall Ingrowths ◽  
Wall Ingrowth ◽  
Hartig Net ◽  
Epidermal Cell Wall ◽  
Different Strains ◽  
Cell Wall Ingrowths

Seedlings of Alnuscrispa (Ait.) Pursh, Alnusrubra Bong., Eucalyptuspilularis Sm., and Betulaalleghaniensis Britt. were grown in plastic pouches and subsequently inoculated with Alpovadiplophloeus (Zeller & Dodge) Trappe & Smith (two different strains), Pisolithustinctorius (Pers.) Coker & Couch, and Laccariabicolor (R. Mre) Orton, respectively, to form ectomycorrhizae insitu. Alnus seedlings were inoculated with Frankia prior to inoculation with the mycosymbiont. The interface established between A. crispa and A. diplophloeus was complex, involving wall ingrowth formation in root epidermal cells and infoldings in Hartig net hyphae. Alnusrubra – A. diplophloeus ectomycorrhizae had an interface lacking epidermal cell wall ingrowths but with infoldings in Hartig net hyphae. The interface between E. pilularis –. tinctorius consisted of branching Hartig net hyphae between radially enlarged epidermal cells lacking wall ingrowths. Ectomycorrhizae between B. alleghaniensis and L. bicolor developed unique interfaces with radially enlarged epidermal cells near the apical meristem, which synthesized dense vacuolar deposits. Very fine branchings occurred in Hartig net hyphae.

Ontogeny of Eucalyptus pilularis – Pisolithus tinctorius ectomycorrhizae. II. Transmission electron microscopy

1987 ◽  
Vol 65 (9) ◽  
pp. 1940-1947 ◽  
Author(s):  
H. B. Massicotte ◽  
R. L. Peterson ◽  
C. A. Ackerley ◽  
A. E. Ashford
Keyword(s):  
Cortical Layer ◽  
Epidermal Cells ◽  
Root Cap ◽  
Pisolithus Tinctorius ◽  
Dense Layer ◽  
Hartig Net ◽  
Transmission Electron ◽  
Fungal Hyphae ◽  
Cytoplasmic Content ◽  
Eucalyptus Pilularis

Eucalyptus pilularis – Pisolithus tinctorius ectomycorrhizae were synthesized in growth pouches, and ultrastructural features of the two symbionts were documented during ontogeny. In the root cap – meristem zone, fungal hyphae envelop the root cap and penetrate between root cap cells. These fungal hyphae have numerous organelles and nuclei, some of which are in mitosis. The inner mantle hyphae in this zone and in the pre-Hartig net zone are heterogeneous in cytoplasmic content and are separated from the epidermis by an electron-dense layer. In the young Hartig net zone, hyphae penetrate between epidermal cells which contain electron-dense vacuolar deposits. In this zone and in the older Hartig net zone, hyphae do not penetrate beyond the epidermis and therefore a paraepidermal Hartig net is formed. The outer cortical layer develops as a hypodermis with suberized cell walls. The root–fungus interface consists of Hartig net hyphae which form a labyrinthine wall system and epidermal cells which are enlarged radially and contain electron-dense vacuolar deposits.

Localization of three sugar residues in the interface of ectomycorrhizae synthesized between Alnus crispa and Alpova diplophloeus as demonstrated by lectin binding

1987 ◽  
Vol 65 (6) ◽  
pp. 1127-1132 ◽  
Author(s):  
H. B. Massicotte ◽  
C. A. Ackerley ◽  
R. L. Peterson
Keyword(s):  
Cell Wall ◽  
Host Cell ◽  
Lectin Binding ◽  
Ulex Europaeus ◽  
Structural Modifications ◽  
Wall Ingrowths ◽  
Alnus Crispa ◽  
Hartig Net ◽  
Host Cell Wall ◽  
Mycorrhizal Roots

The interface established between Alnus crispa and the basidiomycete Alpova diplophloeus involves structural modifications of host cell walls and hyphal walls in the Hartig net region of the ectomycorrhizae synthesized in pouches. Indirect labelling of cell wall carbohydrates by using colloidal gold conjugated with the lectins Ulex europaeus agglutinin, wheat-germ agglutinin, and concanavalin A was applied to these mycorrhizae and to nonmycorrhizal roots. Significantly more binding of the lectins was observed in the mycorrhizal roots than in control roots. In the Hartig net region of mycorrhizal roots, the lectins bound intensely to the host cell wall, particularly the wall ingrowths, and to adjacent fungal walls, whereas in nonmycorrhizal roots, a sparse labelling was recorded in the cell wall. Possible explanations for this pattern of lectin binding include the following: the sugar residues L-fucose, mannose, and N-acetylglucosamine may be utilized in the synthesis of the elaborate epidermal wall ingrowths and N-acetylglucosamine may be utilized in the synthesis of the labyrinthine wall branchings of the fungus; the sugar residues are bound to a proteinaceous fraction in the host and hyphal walls; the sugar residues bound by the lectins may be components of defense reaction elicitors released from the host wall and hyphal wall by wall-degrading enzymes; the sugar residues may simply be the result of enzymatic degradation of walls but not involving elicitors of defense reactions.

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.

Ultrastructural aspects of Pyrola mycorrhizae

1985 ◽  
Vol 63 (6) ◽  
pp. 1089-1098 ◽  
Author(s):  
Diane C. Robertson ◽  
Jack A. Robertson
Keyword(s):  
Epidermal Cell ◽  
Matrix Material ◽  
Root Surface ◽  
Root Tip ◽  
Host Cytoplasm ◽  
Hartig Net ◽  
Arbutoid Mycorrhizae ◽  
Fungal Hyphae ◽  
Host Origin ◽  
Electron Microscopes

The mycorrhizae of six species of Pyrola were examined with light and electron microscopes. The hyphae on the root surface varied from a loose weft to an abundant mass with numerous strands, but no organized sheath was observed. Infection began with the formation of a Hartig net several millimetres behind the root tip. Hyphae from this net subsequently grew into each epidermal cell, forming masses of intracellular hyphae. These hyphae were surrounded by the host plasmalemma and a matrix material, presumably of host origin. During the stage of mature infection the host cytoplasm was finely granular and filled with organelles. The host vacuoles often had tanninlike deposits along their tonoplasts. Senescence of the symbiosis began with the gradual degeneration of the host cytoplasm, which became dark and vesiculated with loss of its organelles. The fungal hyphae and matrix material appeared essentially unchanged at this stage but eventually degenerated and collapsed. The fungal partners were normally basidiomycetes with dolipore septa, but one ascomycetous infection (distinguished by simple septa and Woronin bodies) was found to have a similar mycorrhizal organization. It differed in having an intermittent Hartig net. The presence of both the Hartig net and intracellular hyphae indicates that these are arbutoid mycorrhizae.

CoGRIM19 is required for invasive hyphal growth of Colletotrichum orbiculare inside epidermal cells of cucumber cotyledons

2021 ◽  
pp. 104847
Author(s):  
Ken Harata ◽  
Hayato Shinonaga ◽  
Yuudai Nishiyama ◽  
Tetsuro Okuno
Keyword(s):  
Hyphal Growth ◽  
Epidermal Cells ◽  
Colletotrichum Orbiculare ◽  
Cucumber Cotyledons

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 A Novel Class of Ectomycorrhiza-Regulated Cell Wall Polypeptides in Pisolithus tinctorius

1999 ◽  
Vol 12 (10) ◽  
pp. 862-871 ◽  
Author(s):  
Pascal Laurent ◽  
Catherine Voiblet ◽  
Denis Tagu ◽  
Dulcinéia de Carvalho ◽  
Uwe Nehls ◽  
...  
Keyword(s):  
Cell Wall ◽  
Cell Adhesion ◽  
Polyacrylamide Gel Electrophoresis ◽  
State Level ◽  
Root Surface ◽  
Pisolithus Tinctorius ◽  
Surface Proteins ◽  
Ectomycorrhizal Symbiosis ◽  
Fungal Cell ◽  
Fungal Hyphae

Development of the ectomycorrhizal symbiosis leads to the aggregation of fungal hyphae to form the mantle. To identify cell surface proteins involved in this developmental step, changes in the biosynthesis of fungal cell wall proteins were examined in Eucalyptus globulus-Pisolithus tinctorius ectomycorrhizas by two-dimensional polyacrylamide gel electrophoresis. Enhanced synthesis of several immunologically related fungal 31- and 32-kDa polypeptides, so-called symbiosis-regulated acidic polypeptides (SRAPs), was observed. Peptide sequences of SRAP32d were obtained after trypsin digestion. These peptides were found in the predicted sequence of six closely related fungal cDNAs coding for ectomycorrhiza up-regulated transcripts. The PtSRAP32 cDNAs represented about 10% of the differentially expressed cDNAs in ectomycorrhiza and are predicted to encode alanine-rich proteins of 28.2 kDa. There are no sequence homologies between SRAPs and previously identified proteins, but they contain the Arg-Gly-Asp (RGD) motif found in cell-adhesion proteins. SRAPs were observed on the hyphal surface by immunoelectron microscopy. They were also found in the host cell wall when P. tinctorius attached to the root surface. RNA blot analysis showed that the steady-state level of PtSRAP32 transcripts exhibited a drastic up-regulation when fungal hyphae form the mantle. These results suggest that SRAPs may form part of a cell-cell adhesion system needed for aggregation of hyphae in ectomycorrhizas.

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