Blastocladiomycota

Blastocladiomycota

Blastocladiales
Scientific classification
Kingdom: Fungi
Phylum: Blastocladiomycota
Class: Blastocladiomycetes
T.Y.James (2006)
Order: Blastocladiales
T.Y.James (2006)
Families

Blastocladiaceae
Catenariaceae
Coelomomycetaceae
Physodermataceae
Sorochytriaceae

Blastocladiomycota is one of the currently recognized phyla within the kingdom [4]

Morphology

Morphology in Blastocladiomycota varies greatly. For example, members of Coelomycetaceae are simple, unwalled, and plasmodial in nature. Some species in Blastocladia are monocentric, like the chytrids, while others are polycentric. The most remarkable are those members, such as Allomyces that demonstrate determinant, differentiated growth.[3][4]

Reproduction/Life Cycle

Sexual Reproduction

As stated above, some members of Blastocladiomycota exhibit haploid phase, the thallus forms male and female gametangia that release flagellated gametes. Gametes attract one another using pheromones and eventually fuse to form a Zygote. The germinated zygote produces a diploid thallus with two types of sporangia: thin-walled zoosporangia and thick walled resting spores (or sporangia). The thin walled sporangia release diploid zoospores. The resting spore serves as a means of enduring unfavorable conditions. When conditions are favorable again, meiosis occurs and haploid zoospores are released. These germinate and grow into haploid thalli that will produce “male” and “female” gametangia and gametes.[4]

Asexual Reproduction

Similar to Chytridiomycota, members of Blastocladiomycota produce asexual zoospores to colonize new substrates. In some species, a curious phenomenon has been observed in the asexual zoospores. From time to time, asexual zoospores will pair up and exchange cytoplasm but not nuclei.[3]

Ecological Roles

Similar to Chytridiomycota, members of Blastocladiomycota are capable of growing on refractory materials, such as pollen, keratin, cellulose, and chitin.[3] The best known species, however, are the parasites. Members of Catenaria are parasites of nematodes, midges, crustaceans, and even another blastoclad, Coelomyces.[4] Members of the genus Physoderma and Urophlyctis are obligate plant parasites.[4] Of economic importance is Physoderma maydis, a parasite of maize and the causal agent of brown spot disease.[4] Also of importance are the species of Urophlyctis that parasitize alfalfa.[7] However, ecologically, Physoderma are important parasites of many aquatic and marsh angiosperms.[3] Also of human interest, for health reasons, are members of Coelomyces, and unusual parasite of mosquitoes that require an alternate crustacean host (the same one parasitized by members of Catenaria) to complete its life cycle.[3] Others that are ecologically interesting include a parasite of water bears and the zooplankter Daphnia.[7]

References

  1. ^ Hibbett DS et al. 2007. A higher-level phylogenetic classification of the fungi. Mycological Research 111:509–47.
  2. ^
  3. ^ a b c d e f g Sparrow FK. 1960. Aquatic phycomycetes. 2nd ed. Ann Arbor, Michigan: University of Michigan Press.
  4. ^ a b c d e f g h Alexopoulos CJ, Mims CW, Blackwell M. 1996. Introductory Mycology. 4th edition. John Wiley & Sons, Inc.
  5. ^ Porter TM ‘’etal’’ 2011. Molecular phylogeny of the Blastocladiomycota (Fungi) based on nuclear ribosomal DNA. Fungal Biology 115:381-392.
  6. ^ Kendrick, Bryce. 2000. The Fifth Kingdom. 3rd edition Focus Publishing: Newburyport, MA.
  7. ^ a b

External links