Plant Transformation Overview
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.
icon search Searchable Transcript
Toggle between list and paragraph view.
[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.
Log in to post comments