Midterms
Progress
Oomycete Biology
Not a lot has happened this week. I have spent a lot of time identifying the mushrooms that I have collected for my mycology class. I am waiting for the lab technicians to grow some of the Phytophthora spp. I asked for from storage onto plates so that I can begin to work with them.
I thought I’d take this opportunity to explain a little of the biology of the organism that I am working with. Phytophthora is the genus and there are a bunch of species within this genus which are economically significant plant pathogens. Phytophthora spp. are Oomycetes (commonly termed the water moulds). ‘Oomycota’ is the taxonomic Phylum, and this is in the Kingdom ‘Stramenophila’, not the Kingdom Fungi as they were once classified. Oomycetes are sometimes termed pseudofungi as they closely resemble Fungi.
The key features which distinguish the oomycetes from the real fungi are their cell walls and their spores. Real fungal cell walls contain chitin, but the oomycete cell walls contain cellulose (as do plant cell walls). The hyphae of pseudofungi are not separated by septae, and the mycelial nucleus is diploid, with two sets of chromosomes. Oomycetes can reproduce both sexually (oospores) and asexually (sporangia, zoospores, chlamydospores). Zoospores are motile with two hair-like flagella propelling the zoospore through liquid, oospores, on the other hand, are non motile. In general sporangia are the survival and dispersal mechanism and zoospores are the infection mechanism.
Federal Holiday
Aside from this I am still working on identifying the isolates I am going to work with initially and then getting them growing on plates so that I can actually begin some detached leaf inoculations and stuff.
And one other thing - I just added a new link to my photography page which at the moment only has some photos from the work I did at Rothamsted this summer, but there will be more to come, including microscopy images and specimens from my mycology collection for a class I am taking this term.