Interactions between a fungal endophyte and gametophyte cells in Psilotum nudum

1981 ◽  
Vol 59 (5) ◽  
pp. 711-720 ◽  
Author(s):  
R. L. Peterson ◽  
Melanie J. Howarth ◽  
Dean P. Whittier
Keyword(s):  
Energy Source ◽  
Endophytic Fungus ◽  
Cell Walls ◽  
Fungal Endophyte ◽  
Hyphal Cell ◽  
Cell Organelles ◽  
Host Cytoplasm ◽  
Psilotum Nudum ◽  
Parenchyma Cells ◽  
Fungal Hyphae

Mature Psilotum gametophytes found in greenhouse pots containing plants of Hoya, Philodendron, Aspidistra, or Diffenbachia were processed for microscopy. An endophytic fungus was abundant in the rhizoids and in most cortical parenchyma cells except at the growing apices. Although the fungus has not been identified, it is an aseptate fungus with coarse hyphae which occasionally form vesicles. Endophytic fungal hyphae store quantities of lipid which appear to be released into the host cytoplasm upon fungal degeneration. This lipid and the remnants of hyphal cell walls may be used as an energy source by the achlorophyllous gametophyte. Gametophyte cell organelles, including the nucleus, appear to degenerate after fungal breakdown, and the cells presumably die. Although reinfection of cells containing degenerated hyphae was found, it was not particularly common.

The Hyphal Plexus of Psilotum Nudum Gametophytes

1972 ◽  
Vol 30 ◽  
pp. 232-233
Author(s):  
D. K. Walker ◽  
R. W. Davis
Keyword(s):  
Ultrastructural Study ◽  
Endophytic Fungus ◽  
Vascular Plants ◽  
Large Body ◽  
Cell Lumen ◽  
Psilotum Nudum ◽  
Mycorrhizal Association ◽  
Fungal Hyphae ◽  
Organic Nutrients

The subterranean gametophyte thallus of Psilotum nudum, like some other lower vascular plants, forms a mycorrhizal-association with an endophytic fungus. The achlorophyllous prothallium is capable of synthesizing starch while growing in the dark. Presumably, the intracellular fungal hyphae within the prothallial cells aid the gametophyte in obtaining at least part of its basic organic nutrients.Each of the older Psilotum cells develops a single large body near the center of the cell lumen. These bodies are larger than the nuclei of the prothallial cells, but have similar affinities for acidiphilic dyes. This ultrastructural study of Psilotum gametophyte thalli was begun to determine the nature of these unusual bodies.

scholarly journals New α-pyrones from an endophytic fungus, Hypoxylon investiens J2

RSC Advances ◽  
2019 ◽  
Vol 9 (47) ◽  
pp. 27419-27423 ◽  
Author(s):  
Chao Yuan ◽  
Hong-Xia Yang ◽  
Yu-Hua Guo ◽  
Lin Fan ◽  
Ying-Bo Zhang ◽  
...  
Keyword(s):  
Medicinal Plant ◽  
Endophytic Fungus ◽  
Fungal Endophyte

Four new α-pyrones, hypotiens A–D (1–4), were isolated from a fungal endophyte, Hypoxylon investiens J2, harbored in the medicinal plant Blumea balsamifera.

A light and electron microscope study of the fungal endophytes in the sporophyte and gametophyte of Lycopodium cernuum with observations on the gametophyte–sporophyte junction

1992 ◽  
Vol 70 (1) ◽  
pp. 58-72 ◽  
Author(s):  
Jeffrey G. Duckett ◽  
Roberto Ligrone
Keyword(s):  
Root Nodules ◽  
Fungal Endophytes ◽  
Fungal Endophyte ◽  
Peninsular Malaysia ◽  
Epidermal Cells ◽  
Host Cells ◽  
Wall Material ◽  
Intercellular Spaces ◽  
Host Cytoplasm ◽  
Fungal Associations

The ventral epidermal cells of the photosynthetic, surface-living gametophytes of Lycopodium cernuum, collected from moist shaded banks in Peninsular Malaysia, contain an aseptate fungus. In some cells the hyphae are thick walled and form coils encapsulated by a thin layer of host wall material. In others the fungus is thin walled and shows limited differentiation into larger trunk hyphae and arbuscules. The adjacent host cytoplasm, separated from the fungus by a granular interfacial matrix, contains numerous chloroplasts, mitochondria, and microtubules. The hyphae contact the substratum via the ventral walls of the epidermal cells and the rhizoids are free from infection. In the protocorm and root nodules, aseptate hyphae initially colonize mucilage-filled schizogenous intercellular spaces. Subsequent invasion of the host cells is associated with the development of massive overgrowths of host wall material. The fungal associations in L. cernuum share a mixture of attributes otherwise found in different angiosperm mycorrhizae and in mycotrophic relationships in liverworts. Wall ingrowths are present in both the gametophyte and sporophyte cells in the placenta of L. cernuum. The very limited development of the placenta, compared with L. appressum, certain bryophytes and ferns, the diminutive size, and early senescence of the gametophytes of L. cernuum are all linked to the presence of the protocorm. This massive absorptive organ, homologous to a foot, in terms of its position in sporophyte ontogeny, but external to the parent gametophyte, derives its nutrition partly from photosynthesis and partly from its fungal endophyte. Key words: chloroplasts, Lycopodium, mycorrhiza, pteridophytes, root nodules, symbiosis, transfer cells.

The morphology of grain abscission in Zizania aquatica

1980 ◽  
Vol 58 (21) ◽  
pp. 2269-2273 ◽  
Author(s):  
H. B. Hanten ◽  
G. E. Ahlgren ◽  
J. B. Carlson
Keyword(s):  
Wild Rice ◽  
Cell Walls ◽  
Vascular Tissue ◽  
Embryo Sac ◽  
Middle Lamella ◽  
Abscission Zone ◽  
Rice Grains ◽  
Zizania Aquatica ◽  
Parenchyma Cells ◽  
Anatomical Evidence

The anatomical development of the abscission zone in grains of Zizania aquatica L. was correlated with development of the embryo. The abscission zone is well developed when the embryo sac is mature. Soon after pollination, the first anatomical evidence of abscission appears as plasmolysis of the separation layer parenchyma cells. This is followed by separation of the layers by dissolution of the middle lamella and fragmentation of cell walls. Persistence of intact vascular tissue and presence of a surrounding cone-shaped mass of lignified cells may be involved in abscission of wild rice grains.

scholarly journals Treatment with the Mycoparasite Pythium oligandrum Triggers Induction of Defense-Related Reactions in Tomato Roots When Challenged with Fusarium oxysporum f. sp. radicis-lycopersici

1997 ◽  
Vol 87 (1) ◽  
pp. 108-122 ◽  
Author(s):  
Nicole Benhamou ◽  
Patrice Rey ◽  
Mohamed Chérif ◽  
John Hockenhull ◽  
Yves Tirilly
Keyword(s):  
Plant Defense ◽  
Fusarium Oxysporum ◽  
Host Cell ◽  
Cell Walls ◽  
Pythium Oligandrum ◽  
Tomato Plants ◽  
Host Cytoplasm ◽  
Defense Reactions ◽  
Tomato Roots ◽  
Root Tissues

The influence exerted by the mycoparasite Pythium oligandrum in triggering plant defense reactions was investigated using an experimental system in which tomato plants were infected with the crown and root rot pathogen Fusarium oxysporum f. sp. radicis-lycopersici. To assess the antagonistic potential of P. oligandrum against F. oxysporum f. sp. radicis-lycopersici, the interaction between the two fungi was studied by scanning and transmission electron microscopy (SEM and TEM, respectively). SEM investigations of the interaction region between the fungi demonstrated that collapse and loss of turgor of F. oxysporum f. sp. radicis-lycopersici hyphae began soon after close contact was established with P. oligandrum. Ultrastructural observations confirmed that intimate contact between hyphae of P. oligandrum and cells of the pathogen resulted in a series of disturbances, including generalized disorganization of the host cytoplasm, retraction of the plasmalemma, and, finally, complete loss of the protoplasm. Cytochemical labeling of chitin with wheat germ agglutinin (WGA)/ovomucoid-gold complex showed that, except in the area of hyphal penetration, the chitin component of the host cell walls was structurally preserved at a time when the host cytoplasm had undergone complete disorganization. Interestingly, the same antagonistic process was observed in planta. The specific labeling patterns obtained with the exoglucanase-gold and WGA-ovomucoid-gold complexes confirmed that P. oligandrum successfully penetrated invading cells of the pathogen without causing substantial cell wall alterations, shown by the intense labeling of chitin. Cytological investigations of samples from P. oligandrum-inoculated tomato roots revealed that the fungus was able to colonize root tissues without inducing extensive cell damage. However, there was a novel finding concerning the structural alteration of the invading hyphae, evidenced by the frequent occurrence of empty fungal shells in root tissues. Pythium ingress in root tissues was associated with host metabolic changes, culminating in the elaboration of structural barriers at sites of potential fungal penetration. Striking differences in the extent of F. oxysporum f. sp. radicis-lycopersici colonization were observed between P. oligandrum-inoculated and control tomato plants. In control roots, the pathogen multiplied abundantly through much of the tissues, whereas in P. oligandrum-colonized roots pathogen growth was restricted to the outermost root tissues. This restricted pattern of pathogen colonization was accompanied by deposition of newly formed barriers beyond the infection sites. These host reactions appeared to be amplified compared to those seen in nonchallenged P. oligandrum-infected plants. Most hyphae of the pathogen that penetrated the epidermis exhibited considerable changes. Wall appositions contained large amounts of callose, in addition to be infiltrated with phenolic compounds. The labeling pattern obtained with gold-complexed laccase showed that phenolics were widely distributed in Fusarium-challenged P. oligandrum-inoculated tomato roots. Such compounds accumulated in the host cell walls and intercellular spaces. The wall-bound chitin component in Fusarium hyphae colonizing P. oligandrum-inoculated roots was preserved at a time when hyphae had undergone substantial degradation. These observations provide the first convincing evidence that P. oligandrum has the potential to induce plant defense reactions in addition to acting as a mycoparasite.

scholarly journals Anatomía vegetativa de Ctenitis melanosticta (Dryopteridaceae, Pteridophyta)

2017 ◽  
pp. 7
Author(s):  
Victoria Hernández-Hernández ◽  
Teresa Terrazas ◽  
Klaus Mehltreter
Keyword(s):  
Diagnostic Value ◽  
Anatomical Studies ◽  
Anatomical Features ◽  
Adaxial Epidermis ◽  
Parenchyma Cells ◽  
Fungal Hyphae ◽  
Available Information

The root, rhizome, petiole and blade anatomy of Ctenitis melanosticta was studied and compared with the available information for closely related genera. Root is diarc with sclerenchyma and parenchyma cells in the cortex, with fungal hyphae exclusively in the latter. The occurrence of sclereid nests in the rhizome is shared with Dryopteris and Campyloneurum. A cortical band was present in petiole and lamina, as in Dryopteris and other genera of the most derived ferns. The lamina had unifacial mesophyll and under the adaxial epidermis there were several layers of the fiber, as described for Elaphoglossum and Thelypteris, but differed from Asplenium, Dryopteris, and Polybotrya with collenchyma. The anatomy of C. melanosticta was similar to that of most species studied of Dryopteridaceae, although with some differences. Additional anatomical studies in species of Dryopteridaceae will allow to confirm the diagnostic value of several anatomical features, such as the lack of cortical band in the rhizome, the sclereid nests, the unifacial mesophyll, and the cortical band in the lamina.

Use of cellulase and hemicellulase for the separation of Phytophthora cactorum oospores from mycelium mats

1972 ◽  
Vol 50 (12) ◽  
pp. 2685-2686 ◽  
Author(s):  
B. Sneh
Keyword(s):  
Cell Walls ◽  
Phytophthora Cactorum ◽  
Hyphal Cell

Degradation of Phytophthora cactorum hyphal cell walls in mycelial mats was effected by incubation in a mixture of cellulase and hemicellulase for 7 days; fragments of homogenized mycelium were degraded after only 2 days. Oospore suspensions free from debris were obtained from the enzyme-treated cultures by washing them through nylon nets.

scholarly journals Plasmodesmata-Related Structural and Functional Proteins: The Long Sought-After Secrets of a Cytoplasmic Channel in Plant Cell Walls

2019 ◽  
Vol 20 (12) ◽  
pp. 2946 ◽  
Author(s):  
Xiao Han ◽  
Li-Jun Huang ◽  
Dan Feng ◽  
Wenhan Jiang ◽  
Wenzhuo Miu ◽  
...  
Keyword(s):  
Cell Wall ◽  
Plant Cell ◽  
Cell Walls ◽  
Plasma Membranes ◽  
Plant Cell Wall ◽  
Plant Cells ◽  
Protein Composition ◽  
Cell Contact ◽  
Plant Cell Walls ◽  
Cell Organelles

Plant cells are separated by cellulose cell walls that impede direct cell-to-cell contact. In order to facilitate intercellular communication, plant cells develop unique cell-wall-spanning structures termed plasmodesmata (PD). PD are membranous channels that link the cytoplasm, plasma membranes, and endoplasmic reticulum of adjacent cells to provide cytoplasmic and membrane continuity for molecular trafficking. PD play important roles for the development and physiology of all plants. The structure and function of PD in the plant cell walls are highly dynamic and tightly regulated. Despite their importance, plasmodesmata are among the few plant cell organelles that remain poorly understood. The molecular properties of PD seem largely elusive or speculative. In this review, we firstly describe the general PD structure and its protein composition. We then discuss the recent progress in identification and characterization of PD-associated plant cell-wall proteins that regulate PD function, with particular emphasis on callose metabolizing and binding proteins, and protein kinases targeted to and around PD.

Localisation structurale et ultrastructurale d'activités peroxydasiques dans les parois du mésophylle et des fibres en cours de lignification chez l'alfa (Stipa tenacissima)

1984 ◽  
Vol 62 (12) ◽  
pp. 2644-2649 ◽  
Author(s):  
M. Harche
Keyword(s):  
Peroxidase Activity ◽  
Oxidase Activity ◽  
Cell Walls ◽  
Secondary Wall ◽  
Outer Part ◽  
Potassium Cyanide ◽  
Primary Wall ◽  
Stipa Tenacissima ◽  
Parenchyma Cells

Using diaminobenzidine as substrate, peroxidase activity was localized in the walls of parenchyma cells and differentiating fibres. In mature fibres and parenchyma a slight activity could be recognized in primary walls only. In parenchyma cells, peroxidase activity was fairly inhibited with heat, potassium cyanide, and aminotriazole, which could indicate the presence of catalase within the cell walls. However, in plasmodesmatal regions peroxidases were- resistant to the above inhibitors. Syringaldazine oxidase activity was present only in the primary wall and the outer part of the secondary wall of differentiating fibres. The parallelism between lignification and peroxidase activity in the secondary walls supports the hypothesis of the involvement of these enzymes in the lignification process.

scholarly journals Cell organelles and fluorescence of parenchyma cells in Eucalyptus bosistoana sapwood and heartwood investigated by microscopy

2018 ◽  
Vol 48 (1) ◽  
Author(s):  
Gayatri Mishra ◽  
David A. Collings ◽  
Clemens M. Altaner
Keyword(s):  
Cell Organelles ◽  
Parenchyma Cells
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