Pseudofungi Explained

Pseudofungi is a grouping of heterokonts,^{[1] [2]} also known as the Heterokontimycotina.^[3] It consists of the Oomycetes and Hyphochytriomycetes.^[3] Although numerous biochemical, ultrastructural, and genetic traits clearly place them in the heterokonts, their growth form (featuring hyphae) and mode of nutrition (osmotrophy) resemble that of fungi (which are not closely related).^[3]

Origin and ancestors

It is believed that pseudofungi descend from unicellular algae among the Stramenopiles which lost their plastids. While evidence of these plastids hasn't been found, what has been proven is the existence of endosymbiotic red algae plastids.^[4] From this, a unicellular heterotroph proto-pseudofungi (probably a mushroom parasite) got its fungal genes through horizontal gene transfer, which would have led to the development of convergent fungal multicellularity,^[5] explaining why the cell wall is sometimes made of both chitin and cellulose. The group's interrelationships are as follows:

Notes and References

1. Riisberg I, Orr RJ, Kluge R, etal . Seven gene phylogeny of heterokonts . Protist . 160 . 2 . 191–204 . May 2009 . 19213601 . 10.1016/j.protis.2008.11.004 .
2. Cavalier-Smith T, Chao EE . Phylogeny and megasystematics of phagotrophic heterokonts (kingdom Chromista) . J. Mol. Evol. . 62 . 4 . 388–420 . April 2006 . 16557340 . 10.1007/s00239-004-0353-8. 2006JMolE..62..388C . 29567514 .
3. Van der Auwera G, De Baere R, Van de Peer Y, De Rijk P, Van den Broeck I, De Wachter R . The phylogeny of the Hyphochytriomycota as deduced from ribosomal RNA sequences of Hyphochytrium catenoides . Mol. Biol. Evol. . 12 . 4 . 671–8 . July 1995 . 7659021 . 10.1093/oxfordjournals.molbev.a040245.
4. Richards TA, Talbot NJ . Plant parasitic oomycetes such as phytophthora species contain genes derived from three eukaryotic lineages . Plant Signal Behav . 2 . 2 . 112–4 . 2007 . 19704752 . 2633911 . 10.4161/psb.2.2.3640 .
5. Richards TA, Dacks JB, Jenkinson JM, Thornton CR, Talbot NJ . Evolution of filamentous plant pathogens: gene exchange across eukaryotic kingdoms . Curr. Biol. . 16 . 18 . 1857–64 . 2006 . 16979565 . 10.1016/j.cub.2006.07.052 . free .