Sunday, August 14, 2011

Regulation of Morphology of Corn Smut, Ustilago maydis

Basidiomycota, in contrast to other fungi such as Ascomycota, produce basidia that yield four sexual spores called basidiospores. U. maydis is part of this phylum. Its mating-type is determined by a tetrapolar system with two unrelated loci, a and b. There are two idiomorphs for the a locus, a1 and a2. Haploid U. maydis cells have either the 4.5kb a1 locus with genes mfa1, pra1, and rfa2, or the 8kb a2 locus with genes mfa2, pra2, lga2, and rga2. mfa1 and mfa2 encode pheromone precursors, pra1 and pra2 genes encode pheromone receptors for the a2 and a1 pheromone, respectively. rfa2, lga2, and rga2 are thought to function within mitochondria. The pheromone encoded by one idiomorph will bind to the receptor of the opposite cell type, activating a signaling cascade that induces G2 arrest and the formation of conjugation hyphae. The b locus contains two genes, bE and bW, and regulates the switch to the pathogenic filamentous stage, as well as tumor induction and the formation of teliospores. The complex mating-type regulation is not specific to U. maydis, and other Basidiomycetes such as Schizophyllum commune and Coprinus cinereus.

Promycelium undergoes meiosis to produce saprophytic haploid cells. When in contact with corn, these sporidia exchange pheromones and become conjugative hyphae. These fuse to form a dikaryote, which is able to being intracellular invasion. Tumors are induced in which the fungi proliferates. Spores are formed and spread in the air and form a promycelium.

Higher fungi, like U. maydis, make ideal genetic models because they are easy to mate, transform, and select for. Observing metabolism, virulence, genotype is easier because they tend to be linked to readily apparent morphology. U. maydis’ relatedness to animal cells makes their study even more relevant to humans. Not only do does it have microtubule organization, nuclear migration, and nuclear envelop breakdown like in humans, U. maydis has homologues of Homo sapiens proteins that other, “higher” genetic models lack, such as Brh2, a BRCA2 (Breast Cancer Type 2 susceptibility protein) homologue. In vivo studies of Brh2 made it possible for geneticists to understand the function of BRCA2 in DNA repair and tumor suppression in humans. There is no doubt of U. maydis’ importance as a genetic model to study other complex mammalian cell processes. 

No pictures. No sources. Only excellence.

28 scientific replies:

DWei said...

So this means no more eating fungus right? Good, I hate fungus.

(Also, I can't be a cute, white guy because I'm an average, Asian guy.)

(Also, also, how can a person running a science blog be a derp. :|)

NDofLB said...

Nah, you can still eat corn smut. In fact, it's a delicacy in Mexico known as huitlacoche.

Timothy Bowen said...

Corn smut sounds fun and dirty. lol

M Fawful said...

Corn smut is so scary. A product of monocultures?

Admin said...

A bit more scientific than I normally read, but still cool.

Gareth Thomas said...

Reminds of biology at college, but I'm actually interested this time.

Lady Lunacy said...

what?!? corn smut?? Lolz

Diego Sousa said...

too much fancy words and still i was interested =)

Inverse said...

"Corn Smut" sounds like a Japanese porn flick.

SlogBlog11 said...

Corn Smut. Sweetcorn porn.

Electric Addict said...

So many words I don't understand haha

Neon said...

Wait, what is a Promycelium?

Shaw said...

Hmm, interesting

Sub-Radar-Mike said...

Woah, that's a pretty complex way of mating, fungi are amazing.

That Bastard From Bellingham said...

HAH, corn smut. Having grown up in California originally, yeah I know 'bout corn smut but didn't really know the specifics in such detail.

Seriously, mating-type fungus? I always thought fungi just spored out and the spores grew on other creatures/plants...

@Neon - Googles, my friend. When in doubt, just use "define ," that's what I do.

Dictionary.refrence.com sez "Promycelium - a short filament produced in the germination of a spore that bears small spores and then dies"

This Guy said...

That is some interesting stuff! Didn't know about all of the complexity!

Airanel said...

It mystifies me...makes me wonder what the genetic story has to play in my World History discipline. Cheers for the food for thought mate!

Michael Westside said...

I would've been working with this now if I hadnt dropped out from molecylar bioengineering in college

Natural One said...

"U. maydis, make ideal genetic models because they are easy to mate, transform, and select for" Just like plants! Also some amazing stuff they're doing with plant tissue cultures, I want to try this soooo bad.

GMSoccerPicks said...

Thanks for ruining corn for me hahaha now im scared to eat corn

Kyran said...

Best fungi ever, P. Cubensis, aka magic mushrooms. If this post doesn't make sense to you now, it will after you eat a handful of these little guys.

Some say they're what prompted the evolution from ape to human. I can certainly agree that they make you more receptive to compassion, deep thinking, and higher consciousness, all of which are characteristic of (most) humans as compared to beasts. Although there still are some apes out there that haven't made the switch yet.

Neon said...

Thanks for the answer ;)

Sketchar said...

I know nothing on this subject :c seems interesting though.

convictus said...

that got a huge shoulder shrug out of me. I read the first sentence and my eyes rolled up in my head and blacked out until I found myself typing here.

Fizzums said...

I haven't read all of the back posts, so sorry if this has been answered. Are you a genetics student?

Ting Kubby said...

i won't lie, i clicked cos it had smut in the title.

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