Plant Transformation Overview

Grace Troupe, Presenter Author

10/11/2018 Added

1148 Plays

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Plant transformation is the second step of genetic engineering. This video provides a brief overview of plant transformation to see how the transgene is delivered to the soybean plant. This video also gives context to where we are in the genetic engineering process.

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[00:00:06.760]We've just finished the second step
[00:00:08.350]of genetic engineering in the journey of a gene.
[00:00:11.040]So let's see where a gene has journeyed so far
[00:00:13.620]and do a quick overview.
[00:00:16.079]So first we started in Madan's lab
[00:00:17.810]and he put a soybean promoter
[00:00:21.160]on an arabidopsis coding region to make our transgene.
[00:00:25.120]So he got that all ready in the test tube
[00:00:27.640]and sent the transgene to a plant transformation facility,
[00:00:31.990]where Shirley works.
[00:00:33.780]And her job was to get this gene into a soybean plant.
[00:00:37.570]So let's take a look at how that worked.
[00:00:41.510]It's like we just said,
[00:00:42.343]the goal of plant transformation
[00:00:44.110]is to insert the transgene into your plant.
[00:00:46.830]So for us, it was a soybean.
[00:00:51.150]So how did that gene get into the plant?
[00:00:54.900]Go ahead and pause this video and think about that a second.
[00:00:59.900]Well, what we used was a bacteria that occurs in nature.
[00:01:04.160]And can you guess why I showed you this tree?
[00:01:07.640]Well, see there's lumps on here?
[00:01:09.580]These are tumors that are caused by agrobacterium,
[00:01:13.020]the same bacteria that we used
[00:01:14.440]to insert the gene in the soybean.
[00:01:16.710]So this bacteria in nature delivers its own genes
[00:01:21.280]into plant cells so that the plant
[00:01:23.290]makes food for the bacteria.
[00:01:25.400]And so that's genetic engineering in nature all the time.
[00:01:28.090]And if you start looking around at trees,
[00:01:29.650]you'll start noticing this where you live as well.
[00:01:32.090]It's pretty common.
[00:01:33.370]Even the tree in my front yard has this.
[00:01:36.930]So what we can do is replace some of those genes
[00:01:40.070]on the plasmid inside this bacteria
[00:01:43.200]and the bacteria will deliver
[00:01:46.790]the genes for us into the plant cell.
[00:01:50.130]So that's how we get the gene
[00:01:52.680]into the plant is using this bacteria
[00:01:55.730]that already does this in nature.
[00:02:00.430]So the next question is how we get that gene
[00:02:03.410]into every cell of a plant because that bacteria
[00:02:06.850]just delivers it into one cell at a time.
[00:02:09.750]So how do we get it into an entire plant?
[00:02:14.600]Well, it looks like this, if you remember.
[00:02:17.240]So plants have that special ability called totipotency.
[00:02:21.090]And what was that?
[00:02:23.210]That was where if you give the cell
[00:02:26.130]the right hormones, a single plant cell
[00:02:28.540]can grow into a whole plant.
[00:02:30.440]And so when we get these cells on the plant
[00:02:34.620]that have the new gene,
[00:02:36.070]we give them this right mix of hormones
[00:02:38.350]and so a single cell that gets a transgene
[00:02:40.540]will start dividing and dividing and growing a shoot.
[00:02:43.590]So each one of these shoots
[00:02:45.340]started from one cell that got the new gene.
[00:02:48.930]And these can only grow in this media
[00:02:51.210]if they have the new gene.
[00:02:52.570]And we'll look on the next slide as to why.
[00:02:58.550]So how exactly do we know the gene is in there?
[00:03:01.570]It's in these plants?
[00:03:03.540]Go ahead and pause the video and think about it.
[00:03:09.460]That's right, we had something called marker genes.
[00:03:12.970]So that piece of DNA that we put in the plasmid,
[00:03:17.480]it didn't just have the transgene.
[00:03:19.400]In this specific project,
[00:03:21.440]we used a couple of different marker genes.
[00:03:24.230]And so what were those?
[00:03:26.360]These are ones that help us identify
[00:03:28.950]which plants or cells have the gene in them.
[00:03:33.579]And so let's see what this looked like in this project.
[00:03:37.360]In this project, we had in this gel,
[00:03:40.150]where these new plants are growing, we had antibiotics.
[00:03:43.880]And this antibiotic will kill the plant cell
[00:03:47.060]if it doesn't have this resistance gene.
[00:03:49.410]So if that bacteria didn't deliver the gene
[00:03:51.230]into the plant, it can't grow at all.
[00:03:53.900]And so that means that if a shoot is growing,
[00:03:57.490]then it probably has the transgene.
[00:04:01.370]And then we had a way to double check
[00:04:04.890]once these plants were grown to a larger size,
[00:04:10.420]we had herbicide resistance.
[00:04:12.810]And so if the plant got this new chunk of DNA,
[00:04:16.420]it should be able to resist herbicide.
[00:04:18.310]And so if you put that across a leaf it won't damage it.
[00:04:21.600]And that's a way to double check
[00:04:23.250]that the gene got in there.
[00:04:25.030]And so these are the two marker genes
[00:04:26.990]to help us make sure that this disease resistance
[00:04:29.710]showed up in the plant, since it's really hard
[00:04:31.780]to screen for disease resistance with itty-bitty plants.
[00:04:35.870]It's more practical to use these marker genes.
[00:04:38.940]Saves us a lot of time and money.
[00:04:42.960]All right, so Madan had the transgene,
[00:04:46.440]he sent it to Shirley.
[00:04:47.360]Shirley got it in some soybean plants.
[00:04:49.840]And now she's gonna send it along to a plant breeder
[00:04:52.720]so that he can get this gene bred
[00:04:54.830]into the most elite varieties that farmers want to grow.
[00:04:58.740]So I'll see you in step three.

Plant Transformation Overview

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Plant Transformation Overview

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