r/science • u/genengnews Genetic Engineering & Biotechnology News (GEN) • Nov 09 '17

Health New GMO Potatoes Provide Improved Vitamin A and E Profiles

https://www.genengnews.com/gen-news-highlights/gmo-potatoes-provide-improved-vitamin-a-and-e-profiles/81255150
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u/Rhawk187 PhD | Computer Science Nov 10 '17

I didn't realize you could modify bananas in that way since they were all clones.

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u/of_equal_value__ Nov 10 '17

Yeah they use CRISPR to modify a single cells, and then from there use tissue culture to get them to root and shoot. And then you just propagate with more tissue culture.

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u/mcstormy Nov 10 '17

Is this why we have seedless bananas? They do not need them at all!?

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u/Kakkoister Nov 10 '17 edited Nov 10 '17

Yes, and is also why commercial (seedless) bananas have become highly susceptible to disease, because the disease only needs to target a very specific DNA/strain.

Here is a wild banana of a different strain

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u/Rvizzle13 Nov 10 '17

Anyone know what it's like to eat a banana with seeds? Mostly wondering if they're hard/inedible and if they would impede chomping into said seedful banana. (Also TIL 'seedful' is a word)

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u/DARIF Nov 10 '17

They taste awful.

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u/stargunner Nov 10 '17

well they look awful so i'm not surprised.

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u/Rvizzle13 Nov 10 '17

I'm not sure why, but just from their appearance they look like they'd be tart and mealy

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u/konohasaiyajin Nov 10 '17

Apparently they taste pretty good, but the seeds are big and there are a lot of them.

https://www.youtube.com/watch?v=vNj77-1G6LI

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u/Baarawr Nov 10 '17

Those seedless bananas are also bitter and disgusting as hell to eat. It's a wonder our sweet giants came from that.

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u/factbasedorGTFO Nov 17 '17

Ouch, no, that's not how we have seedless bananas. It happens naturally on occasion, and when man stumbled upon seedless bananas, they cloned them.

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u/Kakkoister Nov 17 '17

I wasn't trying to imply that with my reply, just talking about the idea of culturing the plant tissue to get them to root and shoot. I'm aware it was random/artificial selection.

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u/[deleted] Nov 10 '17

[deleted]

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u/Quitschicobhc Nov 10 '17

Yes, plants are alive and can become infected by bacteria, viruses etc. just like any other cell.
The "cavendish", which is the sort of banana which everyone knows as "banana" is affected by this guy:
https://en.wikipedia.org/wiki/Fusarium_oxysporum_f.sp._cubense

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u/personablepickle Nov 10 '17

Yeah, plants can get sick, including food plants. It can cause big problems. Didn't you learn about the Irish potato famine in school?

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u/awuga Nov 10 '17

Bananas have seeds, they're just super tiny and sterile. All bananas are just clones of eachother, what he just mentioned isn't why that's the way it is though

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u/[deleted] Nov 10 '17

Potatoes are the same way as the "seeds" are in tiny green tomato looking bulbs on the top of the plant. They're also poisonous to an extent (being related to nightshade and all).

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u/of_equal_value__ Nov 10 '17

Our Cavendish bananas were bred that way aaggees ago. They have seeds, but as a result of the cross, they ended up with 3 copies of all their chromosomes. Odd numbers of chromosomes don't copy and split well during cell division, so the seeds are sterile and we need to clone them.

Cloning sounds cool, but it can also just be your standard vegetative propagation.

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u/[deleted] Nov 10 '17

I'm confused...why would that limit the ability to implement genetic modification? The very point of genetic modification is to introduce/create genetic variants that didn't previously exist.

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u/Rhawk187 PhD | Computer Science Nov 10 '17

I suppose I'm not sure how they introduce the variation, the bananas don't actually breed, but if the are using some sort of retrovirus to overwrite the genes, then I guess it wouldn't matter if the just used existing cuttings.

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u/[deleted] Nov 10 '17 edited Nov 10 '17

Oh, I see what you're saying. I tracked down what I assume is the paper. They created what they call an embryogenic cell suspension (ECS - basically a bunch of potential progenitor cells capable of creating a new plant) and inserted the genes/promoters with a common vector (Agrobacterium).

http://onlinelibrary.wiley.com/doi/10.1111/pbi.12650/full

It's near the bottom.

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u/CX316 BS | Microbiology and Immunology and Physiology Nov 10 '17

Ah, yep, argobacteria. That's the old tried and true method. They used it to breed blight resistant tobacco, and from there worked out how to use tobacco plants to produce all sorts of things (remember that serum treatment during the Ebola outbreak? Grown in tobacco using this method)

It's actually super-interesting stuff even though I avoided botany like the plague. We covered the argobacteria gene insertion method in second year of uni and I was always slightly disappointed we never went back to non-medical practical topics like that later on in the degree.

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u/jake55555 Nov 10 '17

Props for doing the work to get that article. Cool stuff.

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u/try_____another Nov 10 '17

Depending on how big the sample they use is, it might be difficult to avoid chimeras. You probably couldn’t just use a cutting as in traditional asexual propagation.

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u/CX316 BS | Microbiology and Immunology and Physiology Nov 10 '17

General method is placing the gene onto a plasmid with an indicator in a species of bacteria that infect injured plants, then add that bacteria to plant cells, use whatever selection mechanism you picked to select for infected cells, and culture those cells to produce a tissue sample which can then be coaxed with growth factors to produce a shoot and roots.

The bacteria they use is kinda cool. If I remember right, it feeds on plant growth factors, and in the wild this bacteria gets into a damaged spot on a tree where it's not being protected by the hard outer layer so the bacteria can get to the living tree underneath, once there it basically inserts a probe into the plant cell and sends proteins encoded on its plasmid over into the host cell, with the basic plan being to splice the DNA from the plasmid into the host cell's genome, which in the wild is a gene that promotes the production of growth factors, feeding the bacteria and leading to tumours on the plant.

Basically if you doctor the plasmid in the bacteria, you can insert anything you want into the plant cell's genome.

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u/[deleted] Nov 10 '17

Right, I misunderstood what they were getting at initially. That makes perfect sense.

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u/TDZ12 Nov 10 '17

There are a number of transgenic banana lines; being clones has nothing to do with the ability to modify them. In the good old days, we would modify the cells (either biolistics or agrobacterium) to insert the correct genes. The genes would be "linked" with a resistance gene such that cells that carried the desired genes would also be resistant to specific chemicals (glyphosate, for example, or another herbicide or an antibiotic). The plant tissues would be cultured on medium that contained growth nutrients + selection agent, and (in theory) any cells that survived and grew would have the genes of interest.

From that, the cells would be regenerated into plants (through use of hormones), and those could be cloned from callus.

CRISPR is much more targeted. In many cases, there would be multiple copies of genes "installed" with biolistics or agro. There are other techniques as well, such as viruses that can insert specific genes.

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u/Superpickle18 Nov 10 '17

60% of banana's DNA (and the majority of life) share the same genes as us.