Cushion Of Conidiogenous

Figure A2 Ascomycotina. (a) A swelling ascus bursting the wall of cleistothecium. (b) Ruptured cleistothecium and ascus. (c) Ascus immediately after discharge of ascospores. (From Ingold, C.T. and Hudson, H.J. (1993). Kluwer Academic Publishers. With permission.)

Nuclear fustion Meiosis

Nuclear fustion Meiosis

Basidium

Figure A3 Basidiomycotina. Diagram of basidium development. From Ingold, C.T. and Hudson, H.J. (1993). With kind permission of Kluwer Academic Publishers.

Pileus tissue

2 mm

Pileus

Gills Annulus

Pileus

Stipe

Trama

Gills Annulus

Trama

Basidium

Hymenium

Sub-hymenium (c)

Basidium

Hymenium

Sub-hymenium (c)

Figure A4 Basidiomycotina. Fruit body (sporophore) with cap (pileus) and lamellae (gills) (a), vertical section of cap (b) showing enlarged view of basidium. From Ingold, C.T. and Hudson, H.J. (1993). With kind permission of Kluwer Academic Publishers.

Phylum Ascomycotina

The hyphae are compartmented, typically branched and septate with septal pores. Asexual reproduction is by means of uninucleate or multinucleate conidia. The sexual spores are produced in a sac called an ascus that usually contains four or eight ascospores. Example: Neurospora, Sphaerotheca (Figure A2).

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Figure A5 Basidiomycotina. Life cycle of Puccinia graminis, a heteroecious, obligate plant pathogen. (From Ingold, C.T. and Hudson, H.J. (1993). The Biology of Fungi. Kluwer Academic Publishers. With permission.)

Phylum Basidiomycotina

Comprised of the second biggest group of fungi with some 16,000 species. Hyphae are compartmented with a characteristic clamp connection at septa. The vegetative mycelium is a dikaryon, each cell containing two sexually compatible, haploid nuclei. The fusion of haploid nuclei produces a transient diploid nucleus in a cell called a teliospore or chlamy-dospore. The diploid nucleus divides to form four meiotic products called basidiospores that, unlike in Ascomycotina, are abjected outside from a tube-like or a club-shaped basidium (Figure A3). Example: Agaricus bisporus (Figure A4), Puccinia graminis (Figure A5).

Phylum Deuteromycotina (Fungi Anamorphici)

Although a large group of fungi with some 10,000 species, it is a "dust-bin" group into which are placed all those species that have no known sexual stage. The mycelium is

Figure A6 Deuteromycotina. Conidiogenous structures and conidia. (a) Myrothecium verrucaria, (b) Verticillium tenerum, (c) Harziella captata, (d) Gliocladium roseum, (e) Gliocladium virens, (f) Trichoderma viride. (From Von Arx, J.A. (1981), The Genera of Fungi Sporulating in Pure Culture. J. Cramer. Koeltz Scientific Books. With permission.)

Deuteromycotina

Figure A7 Deuteromycotina. Conidia produced by a cushion of conidiogenous cells (acervulus). (From Von Arx, J.A. (1981), The Genera of Fungi Sporulating in Pure Culture. J. Cramer. Koeltz Scientific Books. With permission.)

Figure Pycnidium

Figure A8 Deuteromycotina. Pycnidium with conidia. (From Ingold, C.T. and Hudson, H.J. (1993). Kluwer Academic Publishers. With permission.)

Antheridium

Figure A9 Straminipila. Diagram of (a-c) stages in zoosporangium development of Saprolegnia. (d) New sporangium produced by internal proliferation. (e) Encystment and emergence of different form of zoospore (diplanetism). (f) Zoospore with tinsel flagellum directed forwards, and whip-lash flagellum directed backwards. (g) Stages in sexual reproduction. (h) Oogonium with oospore. (From Ingold, C.T. and Hudson, H.J. (1993). Kluwer Academic Publishers. With permission.)

Antheridium

septate, multinucleate, bearing conidia externally on isolated conidiophores (Figure A6), on cushion-like mass of hyphae (Figure A7) or within a flask-like structure (Figure A8).

Some fungi classified in Deuteromycotina have double names, the reason being that the sexual stage was discovered after the binomial given on the anamorphic state became common usage. For example, the sexual (teleomorphic) stage of the fungal pathogen of wheat (the glume blotch), Septoria nodorum, was recognized 130 years after the fungus had been named on the basis of asexual reproductive structures. This is because the asexual stage (anamorph) Septoria nodorum occurs on cereals and grasses during spring and summer in England, whereas the sexual stage Mycosphaerella graminicola develops in the wheat stubble and litter in the autumn. Until such time that the connection is established, the same fungus is given two names for the conidial and sexual stages and is classified separately. It is a challenging task to connect the anamorph and teleomorph states that are produced at different times or in different situations.

Phytophthora

Figure A10 Phytophthora infestans, the causal agent of late blight of potato. (a) Surface view of sporangiophore emerging through stoma. (b) Production of flagellated, motile zoospores from sporangium; encystment and germination. (c). An infected potato leaf. (Ingold, C.T. and Hudson, H.J. (1993). With permission Kluwer Academic Publishers.)

Figure A10 Phytophthora infestans, the causal agent of late blight of potato. (a) Surface view of sporangiophore emerging through stoma. (b) Production of flagellated, motile zoospores from sporangium; encystment and germination. (c). An infected potato leaf. (Ingold, C.T. and Hudson, H.J. (1993). With permission Kluwer Academic Publishers.)

KINGDOM STRAMINIPILA (STRAMENOPILA)

Unicellular or hyphal forms; cell walls composed of cellulose-like (3-1,4 glucan; lacking septa. Characterized by gametangial meiosis, thus having a diploid vegetative phase predominantly diploid; asexual reproduction by means of motile spores (Figures A9 and A10). Sexual reproduction involves gametes of unequal size. The forms placed here have been called the "pseudo fungi." Includes Phytophthora infestans, the causal agent of late blight of potato that provided a great impetus to study of fungi and contributed to development of mycology and plant pathology. However, it is now considered not to be a "true fungus" and is placed in the kingdom Straminipila.

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