Allomyces

MICROBIOLOGY

1. TOPIC :- ALLOMYCES Presented by : Samadrita Banik ST. GEORGE COLLEGE M.Sc Microbiology

2. INTRODUCTION Allomyces  is a  genus  of fungi in the family  Blastocladiaceae . It was  circumscribed  by British mycologist  Edwin John Butler  in 1911. Species in the genus have a polycentric thallus and reproduce  asexually  by  zoospores  that have a whiplash-like  flagella . They are mostly isolated from soils in tropical countries, commonly in ponds, rice fields, and slow-moving rivers .

3. Classification Phylum : Chytridiomycota Division : Blastocladiomycota Class : Blasdiomycetes Order : Blastocladies Genus : Allomyces

4. MORPHOLOGY Allomyces  thalli consist of a cylindrical trunk-like basal cell that gives rise to well-developed, highly branched rhizoids that anchor the thallus to the substrate. The trunk-like basal cell also gives rise to numerous dichotomously branched side branches that terminate as either resistant sporangia, zoosporangia, or gametangia depending on the life cycle stage. Septa are sometimes present, especially at the base of reproductive organs. 

5. Thallus Structure of Allomyces The thallus in all the species is hyphal and is called the mycelium. It is filamentous and attached to the substratum by a tuft of delicate but well formed, branched rhizoidal hyphae constituting the rhizoidal system . From the latter arises a single stout ( strong and thick) but slender hypha forming the lower trunk-like portion. In Allomyces they are not formed in conjunction with cell division. The hyphae are thus multinucleate and coenocytic. The septa in Allomyces are often referred to as false septa because they do not completely separate the protoplasm of adjacent somatic segments.

6. REPRODUCTION In allomyces the zoospore produce diploid zoospore which function as a means of asexual reproduction. Sexual reproduction may be isogamous , angioamus or oogamus. Allomyces has an alternation of generation spends part of its life as a haploid thallus and part as a diploid. Haploid thallus bears male and female gametangia. When a flagellate male gamete fuses with flagellete female gamete , results in a diplod thallus.

7. SIGNIFICANCE Allomyces  species seem to have a global distribution and are readily isolated from soils and waters by baiting with a sterile seed .  Species of  Allomyces  can be parasitized by  Catenaria allomyces,   Rozella allomyces , and  Olpidium allomycetos.

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