Monoblepharidomycetes: Classification and characteristics

Members of the Monoblepharidomycetes have a filamentous thallus that is either extensive or simple and unbranched. They frequently have a holdfast at the base. In contrast to other taxa in their phylum, some reproduce using autospores, although many do so through zoospores. Oogamous sexual reproduction may also occur.

The Monoblepharidomycetes is the sister class of the Chytridiomycetes in the phylum Chytridiomycota.

The known genera of this class have thalli. That is either monocentric and without rhizoids, or produce hyphae with an independent evolutionary origin from the hyphae of higher fungi.

The fungi can be isolated by baiting soil sample in water with hemp and sesame seeds.

Classification of Monoblepharidomycetes

Scientific Classification

Monoblepharidomycetes consist of single order Monoblepharidales in which only 30 species and 7 genera are included, most of which are saprobes that grow in freshwater on submerged twigs and fruits.

Some authors recognize the monoblephs as a separate phylum Monoblepharidomycota containing two class Monoblepharidomycetes and Hyaloraphidiomycetes but here we consider them at the class level.

The 7 Genera are distinguished in part by their thallus characteristic:

I) Polycentric mycelial thallus:

  1. Gonapodya
  2. Monoblepharella
  3. Monoblepharis 

II) Uniaxial thallus

  1. Oedogonimyces
  2. Harpochytrium
  3. Hyaloraphidium
  4. Telasphaerula

When hyphae are present in Monoblepharidales, they appear foamy or reticulate because the protoplasm is highly vacuolated.

Monoblepharis polymorpha has a well-developed branched thallus consisting of hyphae with a foamy appearance.

Monoblepharidales is of special interest because of its unique method of sexual reproduction using a nonmotile female gametangium and a flagellated male gamete, unlike any other fungus.

Sexual Reproduction:

As we discuss above it reproduces using nonmotile female gametangium and a flagellated male gamete. Let’s see how it occurs.

Elongated Zoosporangia are borne singly at the hyphal tips subtended by a septum. Zoospores are released from the tip of the sporangium. After released from the tip of sporangium it swims for a time.

After that, it becomes rounded, and germinate by a germ tube to form a new mycelium. The same thallus that bears sporangia also produces gametangia when subjected to higher temperatures.

The elongated male gametangium is borne on the large, rounded egg-like female gametangium.

Uniflagellate gametes formed within the male gametangium. However, When it matures it is released from male gametangium.

A single mature male gamete fertilizes the enlarged female gamete, resulting in cytoplasmic fusion and production of a diploid zygote.

The zygote functions as a resting spore and germinates by producing a hypha to initiate a new thallus. The site of meiosis has not been demonstrated but probably occur in the early division of the zygote nucleus

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