Oomycete Biology - an alternative version

following on from the post Oomycete biology, and alternative version by David Brock:

Phytophthora is the beautiful wife of the Greek tycoon Genius. A bunch of speculators work with the Genius plotting to overthrow the Pathogens, the economically significant supporters of Phytophthora. She is in love with Oomycetes (better known as Walter Mitty). With his sister Oomycota he escapes her by taking a taxi to Phylum in the Kingdom of Stramenophila, leaving her in the Kingdom of Fungi where she listens to classical music. The Fungi fight off Oomycetes who forever after is called Pseudofungi by the people of Fungi.

In Act II Queen Stramenophila, from her cell high above the Chitin, distinguishes Oomycetes far off, separates from her husband Septae and, to defeat Mycelial (who has deployed nuclear weapons), sends her servant Sporangia to Oomycetes with the key to her cell.

Unfortunately, Flagella, the composer, died before he could finish the work though notes for Act III suggest there was the usual hanky panky you get in opera.

And by Clare - by way of an update on my cultures, and inspired by David to use as much mycological jargon as possible:

Phytophthora cactorum and P. citricola are homothallic (they don’t need a partner) and therefore are individually prolific in their production of sexual oospores invitro. P. cinnamomi has produced a few chalymidospores (asexual resting spores) but refuses to produce any sporangia invitro without an offering of soil extract. P. cambivora is beginning to produce the sporangia desired for the preparation of zoospore inoculum to infect my rhododendrons. The others are still in the hyphal state but I have made some three plug plates in the hope that this may excite some of the isolates to reproduce. If not then further action must be taken to induce the production of sporangia.

Photos

New photos are arriving here.

The general plan so far

So far Nik and I have discussed rough plans for three projects to possibly result and a publication each and therefore form three chapters in my thesis.

One project will be to compare different leaf wetness sensors available (with the use of a weather station and data logger). This could result in a methods type paper.

Another project will be characterising the disease symptoms and comparing disease progress of various Phytophthora spp over the seasons of the year on Rhododendron starting in controlled environments and then moving to the field with non quarantine Phytophthora spp (this will also utilise weather station data which is an important consideration in epidemiology).

Finally a similar project but to looking at quarantine Phytophthoras such as P. ramorum and P. nemorosa so this work will not be in the field but in the quarantine chamber unless we set up a field station in an infected county in Oregon or California at a later date.

The first two projects are underway and I hope to complete the first in my first year.

Midterms

While last week turned out to be rather unproductive on the research front due to midterm exams, this week has been jam packed. I have been in the office/lab most of the time and I've started to play around with the brand new weather station equipment, it's all here set up in my office and I've been wiring different sensors into the data logger and I'm learning to program the software to instruct the data logger on how to collect and manipulate the signals into data. I also went through my cultures with Virginia yesterday and they are all going really well, they are growing fast and there were sporangia on one of the species, chlaymidospores on one, and lots of oospores on two of the Phytophthora spp so that is encouraging. I now need to come up with some strategies for continuing with these isolates and a rough experimental design so that I can start to do something with them. I have a meeting with Walt and Nik tomorrow to talk about the weather stations and plan the experiment in more detail.

Progress

At last I have got to doing some practical work. This week I obtained isolates of Phytophthora species from the long term storage in our lab and from another lab on campus also working on Phytophthora spp. and I transfered them onto bigger plates to get them going a little and hopefully begin to play with them and try to get some of them sporulating so that I can move on to inoculate some Rhododendron leaves. I also had a meeting with Nik and Walt about an idea to study leaf wetness sensors so I am going to learn to use the weather station and try to get things set up in my office for that too. Aside from these things it is midterms week so I have had two tests and on Friday I have a lab practical exam for mycology.

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

So I went into work at around noon today, after classes this morning only to find the office shut, the doors locked and hardly anyone there and it turns out that it is Columbus day which means a bunch of people skip work for the day, but schools are still in session. Well, Nik was still in his office so I was able to talk to him and we discussed a bit about the directions of my research and the possibilities for the content of my thesis. He suggests that I should plan for between 3 and 6 chapters and that I should treat each chapter like a paper with the potential for publication. He also came up with a new idea about doing a study on the differences between various leaf wetness sensors which could result in a methods paper publication which has a guaranteed high citation rate and would be a good starter project for me to get me familiar with the weather station equipment and the statistical tools used in epidemiological studies.

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.