Phycomycetes Fungi: Phycomycetes are known as the lowest class of true fungi. Phycomycetes organisms are located all over the world in soil, animal manure, and on fruits. Frequently, the fungi of this class are found in refrigerators and are commonly called bread molds.

Characteristics of Phycomycetes fungi

• Phycomycetes Fungi are also called as algal fungi, and they are found in aquatic habitats, damp places, and on decaying wood in moist or as an obligate parasites on plants.
• They can be parasites or saprophytes.
• Mycelium is coenocytic and aseptate
• The wall of the hyphae is made up of cellulose.
• Asexual reproduction takes place by zoospores (motile) or aplanospores(non-motile).
• Sexual reproduction takes place by gametangial contact, in which male gamete is transferred from the antheridium to the oogonium.
• At the end of sexual reproduction, oospores will be produced.
• Common examples are- Rhizopus, Mucor, and Albugo.

Classification of Phycomycetes fungi

Phycomycetes Fungi are further classified into 3 subclasses based on the method and result of sexual reproduction, and their somatic structures:

 Archimycetes

• The non-mycelial thallus will be round or lob-shaped because of the enlargement of zoospores.
• They sometimes possess rhizoids.
• Their higher forms may be developed into rudimentary mycelium.
• Includes 3 orders:
  • Chytridiales: They are often known as chytrids. They include both soil and aquatic inhabiting species. They are an order of water molds.
  • Ancylistales: They are an unusual member of aquatic Phycomycetes. Sporophores are generally unbranched or rarely branched, having one conidium per branch.
  • Protomycetales: They are spore sac compounds. They are a small group of plant-parasitic Archimycetes.

Oomycetes

• They have well-developed coenocytic mycelium.
• Oogamy is their mode of sexual reproduction.
• Mostly motile zoospores are the accessory spores formed in most of them.
• Includes 5 orders:
  • Blastocladiales: They have a thallus that consists of branched and single basal cells with sporangia at one end and rhizoids at the other. The genus of Blastocladiales are Blastocladia and the family is Blastocladiaceae.
  • Monoblepharidales: They have simple and unbranched filamentous thallus. They can reproduce through autospores and zoospores. Sometimes oogamous sexual reproduction can occur.
  • Leptomitales: They are an order of water molds. They contain the Apodachlya genus.
  • Saprolegniales: They are an order of freshwater mold. 
  • Peronosporales: many diseases of plants are sometimes classified under this order. They are an order of water molds.

Zygomycetes

• They have well-developed mycelium.
• Conjugation of two gametangia is their mode of sexual reproduction.
• Here accessory spores are non-motile aplanospores, and they are known as sporangiospores and formed within the sporangium.
• It Includes 2 orders-
  • Mucorales: They are typically fast-growing. Their hyphae don’t have septa. These are saprotrophic. A few of them cause animal and human diseases also.
  • Entomophthorales: Most species are the pathogens of insects. Production of ballistic asexual spores is observed in most species. When they don’t land on a suitable host, they make one for themselves.

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By Team Learning Mantras