Difference between Oomycetes and True fungi (Oomycetes vs True Fungi)

Fungi are a group of microscopic as well as macroscopic, spore bearing, chlorophyll lacking, filamentous and heterotrophic thallophytes which reproduce asexually and sexually. Fungi are classified into slime moulds, oomycetes and true fungi. The Oomycetes (water moulds) are primarily aquatic fungi live as saprophytes or parasites. Although oomycetes morphologically similar to true fungi and exhibit absorptive nutrition and thus long classified with them, following features show that there are profound biological differences between oomycetes and true fungi.

Oomycetes	True fungi
Diploid somatic thallus	Haploid somatic thallus
Cellulose cell wall	Chitin present, No cellulose cell wall
Mitochondria cristae, tubular	Mitochondria cristate, plate like
Hydroxyprotine wall protein present	Hydroxyprotine wall protein absent
Lysine biosynthesis  Like plants, use diamino pimelic acid pathway	Like animals, use aminoadipic acid pathway

Oomycetes vs True fungi 

1. Somatic phases of oomycetes are diploid, whereas it is haploid in true fungi.

2. Meiosis occurs in developing sex organs or gametangia

3. Many produce egg cells during sexual reproduction. They are also known as egg fungi.

4. Most members produce swimming biflagellate zoospores with an anterior tinsel flagellum and a posterior whiplash flagellum.

5.The cell wall is mainly cellulosic in composition rather than chitionous as is the case in true fungi.

7. The vegetative thallus resembles the algal thallus in general construction.

8.The hyphal walls off oomycetes contain aminoacid hydroxyprotine which is not found other fungi, but is characteristic of the cell walls of green algae.

9. A number of biochemical synthetic pathways in the oomycetes are very different than those present on all other true fungi. Oomycetes like the plants synthesise lysine using diaminopimelic acid pathway rather than through the aminoadipic acid pathway.

10. Oomycetes have tubular mitochondrial cristae. All other fungi have plate like mitochondrial cristae.

11.Sexual reproduction in oomycetes in oogaamous. It takes place by gametagial contact resulting in a characteristic thick walled resting spore, called an oospore.