TED Talks2016.2.9---Jill Farrant :我們怎樣才能使作物成長離開水

TED Talks2016.2.9---Jill Farrant :我們怎樣才能使作物成長離開水
發佈日期：2016年2月9日
As the world's population grows and the effects of climate change come into sharper relief, we'll have to feed more people using less arable land. Molecular biologist Jill Farrant studies a rare phenomenon that may help: "resurrection plants" — super-resilient plants that seemingly come back from the dead. Could they hold promise for growing food in our coming hotter, drier world?
随着世界人口的增长和气候变化的影响，进入更清晰救灾，我们将不得不使用饲料耕地面积少人多。分子生物学家吉尔Farrant研究罕见的现象，可以帮助：“复苏植物” - 超弹性植物看似来自死而复生。他们很有希望在未来我们的炎热，干燥的世界日益增长的粮食？


=========Google 翻译==========

0:12I believe that the secret to producing extremely drought-tolerant crops, 0:17which should go some way to providing food security in the world, 0:20lies in resurrection plants, 0:23pictured here, in an extremely droughted state. 0:26You might think that these plants look dead, 0:29but they're not. 0:30Give them water, 0:31and they will resurrect, green up, start growing, in 12 to 48 hours. 0:38Now, why would I suggest 0:39that producing drought-tolerant crops will go towards providing food security? 0:45Well, the current world population is around 7 billion. 0:48And it's estimated that by 2050, 0:51we'll be between 9 and 10 billion people, 0:54with the bulk of this growth happening in Africa. 0:57The food and agricultural organizations of the world

1:00have suggested that we need a 70 percent increase 1:03in current agricultural practice 1:05to meet that demand. 1:07Given that plants are at the base of the food chain, 1:10most of that's going to have to come from plants. 1:13That percentage of 70 percent 1:16does not take into consideration the potential effects of climate change. 1:20This is taken from a study by Dai published in 2011, 1:25where he took into consideration 1:27all the potential effects of climate change 1:29and expressed them -- amongst other things -- 1:31increased aridity due to lack of rain or infrequent rain. 1:36The areas in red shown here, 1:38are areas that until recently 1:40have been very successfully used for agriculture, 1:43but cannot anymore because of lack of rainfall. 1:46This is the situation that's predicted to happen in 2050. 1:50Much of Africa, in fact, much of the world, 1:53is going to be in trouble. 1:54We're going to have to think of some very smart ways of producing food. 1:58And preferably among them, some drought-tolerant crops.

2:01The other thing to remember about Africa is 2:04that most of their agriculture is rainfed. 2:08Now, making drought-tolerant crops is not the easiest thing in the world. 2:11And the reason for this is water. 2:14Water is essential to life on this planet. 2:17All living, actively metabolizing organisms, 2:21from microbes to you and I, 2:23are comprised predominately of water. 2:25All life reactions happen in water. 2:28And loss of a small amount of water results in death. 2:31You and I are 65 percent water -- 2:33we lose one percent of that, we die. 2:35But we can make behavioral changes to avoid that. 2:39Plants can't. 2:41They're stuck in the ground. 2:43And so in the first instance they have a little bit more water than us, 2:46about 95 percent water, 2:47and they can lose a little bit more than us, 2:49like 10 to about 70 percent, depending on the species, 2:54but for short periods only. 2:56Most of them will either try to resist or avoid water loss.

3:00So extreme examples of resistors can be found in succulents. 3:04They tend to be small, very attractive, 3:07but they hold onto their water at such great cost 3:10that they grow extremely slowly. 3:13Examples of avoidance of water loss are found in trees and shrubs. 3:18They send down very deep roots, 3:19mine subterranean water supplies 3:21and just keep flushing it through them at all times, 3:23keeping themselves hydrated. 3:25The one on the right is called a baobab. 3:27It's also called the upside-down tree, 3:29simply because the proportion of roots to shoots is so great 3:33that it looks like the tree has been planted upside down. 3:36And of course the roots are required for hydration of that plant. 3:40And probably the most common strategy of avoidance is found in annuals. 3:45Annuals make up the bulk of our plant food supplies. 3:49Up the west coast of my country, 3:50for much of the year you don't see much vegetation growth. 3:54But come the spring rains, you get this: 3:57flowering of the desert. 3:59The strategy in annuals,

4:00is to grow only in the rainy season. 4:03At the end of that season they produce a seed, 4:06which is dry, eight to 10 percent water, 4:09but very much alive. 4:10And anything that is that dry and still alive, 4:13we call desiccation-tolerant. 4:15In the desiccated state, 4:17what seeds can do is lie in extremes of environment 4:19for prolonged periods of time. 4:21The next time the rainy season comes, 4:23they germinate and grow, 4:25and the whole cycle just starts again. 4:28It's widely believed that the evolution of desiccation-tolerant seeds 4:32allowed the colonization and the radiation 4:34of flowering plants, or angiosperms, onto land. 4:38But back to annuals as our major form of food supplies. 4:42Wheat, rice and maize form 95 percent of our plant food supplies. 4:48And it's been a great strategy 4:50because in a short space of time you can produce a lot of seed. 4:53Seeds are energy-rich so there's a lot of food calories, 4:55you can store it in times of plenty for times of famine,

5:00but there's a downside. 5:02The vegetative tissues, 5:03the roots and leaves of annuals, 5:06do not have much 5:07by way of inherent resistance, avoidance or tolerance characteristics. 5:11They just don't need them. 5:12They grow in the rainy season 5:14and they've got a seed to help them survive the rest of the year. 5:17And so despite concerted efforts in agriculture 5:20to make crops with improved properties 5:23of resistance, avoidance and tolerance -- 5:25particularly resistance and avoidance 5:27because we've had good models to understand how those work -- 5:30we still get images like this. 5:32Maize crop in Africa, 5:33two weeks without rain 5:35and it's dead. 5:37There is a solution: 5:39resurrection plants. 5:41These plants can lose 95 percent of their cellular water, 5:45remain in a dry, dead-like state for months to years, 5:49and give them water, 5:50they green up and start growing again. 5:53Like seeds, these are desiccation-tolerant. 5:56Like seeds, these can withstand extremes of environmental conditions.

6:01And this is a really rare phenomenon. 6:03There are only 135 flowering plant species that can do this. 6:08I'm going to show you a video 6:09of the resurrection process of these three species 6:12in that order. 6:13And at the bottom, 6:14there's a time axis so you can see how quickly it happens. 6:56(Applause)

7:02Pretty amazing, huh? 7:03So I've spent the last 21 years trying to understand how they do this. 7:08How do these plants dry without dying? 7:11And I work on a variety of different resurrection plants, 7:13shown here in the hydrated and dry states, 7:16for a number of reasons. 7:17One of them is that each of these plants serves as a model 7:20for a crop that I'd like to make drought-tolerant. 7:23So on the extreme top left, for example, is a grass, 7:26it's called Eragrostis nindensis, 7:28it's got a close relative called Eragrostis tef -- 7:30a lot of you might know it as "teff" -- 7:32it's a staple food in Ethiopia, 7:34it's gluten-free, 7:35and it's something we would like to make drought-tolerant. 7:38The other reason for looking at a number of plants, 7:41is that, at least initially, 7:42I wanted to find out: do they do the same thing? 7:44Do they all use the same mechanisms 7:46to be able to lose all that water and not die? 7:49So I undertook what we call a systems biology approach 7:52in order to get a comprehensive understanding 7:54of desiccation tolerance, 7:56in which we look at everything 7:57from the molecular to the whole plant, ecophysiological level.

8:00For example we look at things like 8:02changes in the plant anatomy as they dried out 8:04and their ultrastructure. 8:05We look at the transcriptome, which is just a term for a technology 8:09in which we look at the genes 8:10that are switched on or off, in response to drying. 8:12Most genes will code for proteins, so we look at the proteome. 8:16What are the proteins made in response to drying? 8:19Some proteins would code for enzymes which make metabolites, 8:23so we look at the metabolome. 8:25Now, this is important because plants are stuck in the ground. 8:28They use what I call a highly tuned chemical arsenal 8:32to protect themselves from all the stresses of their environment. 8:35So it's important that we look 8:37at the chemical changes involved in drying. 8:40And at the last study that we do at the molecular level, 8:43we look at the lipidome -- 8:44the lipid changes in response to drying. 8:46And that's also important 8:47because all biological membranes are made of lipids. 8:50They're held as membranes because they're in water. 8:53Take away the water, those membranes fall apart. 8:56Lipids also act as signals to turn on genes.

9:00Then we use physiological and biochemical studies 9:02to try and understand the function of the putative protectants 9:06that we've actually discovered in our other studies. 9:09And then use all of that to try and understand 9:11how the plant copes with its natural environment. 9:15I've always had the philosophy that I needed a comprehensive understanding 9:19of the mechanisms of desiccation tolerance 9:22in order to make a meaningful suggestion for a biotic application. 9:27I'm sure some of you are thinking, 9:28"By biotic application, 9:29does she mean she's going to make genetically modified crops?" 9:34And the answer to that question is: 9:35depends on your definition of genetic modification. 9:39All of the crops that we eat today, wheat, rice and maize, 9:42are highly genetically modified from their ancestors, 9:45but we don't consider them GM 9:47because they're being produced by conventional breeding. 9:50If you mean, am I going to put resurrection plant genes into crops, 9:54your answer is yes. 9:56In the essence of time, we have tried that approach. 9:59More appropriately, some of my collaborators at UCT,

10:02Jennifer Thomson, Suhail Rafudeen, 10:04have spearheaded that approach 10:05and I'm going to show you some data soon. 10:09But we're about to embark upon an extremely ambitious approach, 10:13in which we aim to turn on whole suites of genes 10:16that are already present in every crop. 10:19They're just never turned on under extreme drought conditions. 10:22I leave it up to you to decide 10:24whether those should be called GM or not. 10:27I'm going to now just give you some of the data from that first approach. 10:31And in order to do that 10:32I have to explain a little bit about how genes work. 10:35So you probably all know 10:36that genes are made of double-stranded DNA. 10:38It's wound very tightly into chromosomes 10:40that are present in every cell of your body or in a plant's body. 10:44If you unwind that DNA, you get genes. 10:47And each gene has a promoter, 10:50which is just an on-off switch, 10:52the gene coding region, 10:54and then a terminator, 10:55which indicates that this is the end of this gene, the next gene will start. 10:59Now, promoters are not simple on-off switches.

11:02They normally require a lot of fine-tuning, 11:05lots of things to be present and correct before that gene is switched on. 11:10So what's typically done in biotech studies 11:13is that we use an inducible promoter, 11:15we know how to switch it on. 11:16We couple that to genes of interest 11:18and put that into a plant and see how the plant responds. 11:22In the study that I'm going to talk to you about, 11:24my collaborators used a drought-induced promoter, 11:27which we discovered in a resurrection plant. 11:29The nice thing about this promoter is that we do nothing. 11:32The plant itself senses drought. 11:35And we've used it to drive antioxidant genes from resurrection plants. 11:40Why antioxidant genes? 11:42Well, all stresses, particularly drought stress, 11:45results in the formation of free radicals, 11:48or reactive oxygen species, 11:50which are highly damaging and can cause crop death. 11:53What antioxidants do is stop that damage. 11:57So here's some data from a maize strain that's very popularly used in Africa.

12:01To the left of the arrow are plants without the genes, 12:04to the right -- 12:05plants with the antioxidant genes. 12:07After three weeks without watering, 12:09the ones with the genes do a hell of a lot better. 12:13Now to the final approach. 12:15My research has shown that there's considerable similarity 12:18in the mechanisms of desiccation tolerance in seeds and resurrection plants. 12:23So I ask the question, 12:24are they using the same genes? 12:26Or slightly differently phrased, 12:28are resurrection plants using genes evolved in seed desiccation tolerance 12:33in their roots and leaves? 12:34Have they retasked these seed genes 12:36in roots and leaves of resurrection plants? 12:39And I answer that question, 12:41as a consequence of a lot of research from my group 12:44and recent collaborations from a group of Henk Hilhorst in the Netherlands, 12:47Mel Oliver in the United States 12:49and Julia Buitink in France. 12:51The answer is yes, 12:53that there is a core set of genes that are involved in both. 12:56And I'm going to illustrate this very crudely for maize, 12:59where the chromosomes below the off switch

13:02represent all the genes that are required for desiccation tolerance. 13:05So as maize seeds dried out at the end of their period of development, 13:09they switch these genes on. 13:12Resurrection plants switch on the same genes 13:15when they dry out. 13:17All modern crops, therefore, 13:19have these genes in their roots and leaves, 13:21they just never switch them on. 13:22They only switch them on in seed tissues. 13:25So what we're trying to do right now 13:27is to understand the environmental and cellular signals 13:29that switch on these genes in resurrection plants, 13:33to mimic the process in crops. 13:35And just a final thought. 13:37What we're trying to do very rapidly 13:39is to repeat what nature did in the evolution of resurrection plants 13:43some 10 to 40 million years ago. 13:46My plants and I thank you for your attention. 13:48(Applause)

0:00译者：马丁Malikėnas审稿：SigitaŠimkutė-Macanko 0:12我认为，如何提高一个极其耐旱植物的秘密， 0:17确保全球粮食供应 0:20位于复兴厂 0:23图为，极度干旱状态。 0:26你可能会认为，这些植物都死了， 0:29但事实并非如此。 0:30给他们水， 0:31他们上升，开花，预计增长超过12-48小时。 0:38那么，为什么我会建议 0:39耐旱作物种植，以确保粮食供应？ 0:45那么，地球上现有人口约7十亿。 0:48据推测，这排在2050年， 0:51地球将会从9日至10十亿人， 0:54随着经济增长的最大部分发生在非洲。 0:57世界粮食和农业组织

1:00他建议，我们需要在增长70％ 1:03当前农业做法会 1:05满足的需求。 1:07的事实，即植物是食物链， 1:10这在很大程度上将来自植物。 1:13其中的一些70％ 1:16忽略可能会导致气候变化的潜在影响。 1:20这是从戴研究采取，于2011年出版， 1:25当他指出， 1:27气候变化的所有潜在影响 1:29他们表示 - 除其他事项外 - 1:31干燥度增加，由于缺少雨水或nelietingumo。 1:36这里有一个红色区域 1:38有，最近 1:40已经在农业非常成功地使用， 1:43但已经废弃，由于缺少雨水。 1:46这其中，据说，将在2050年举行的情况。 1:50非洲的一部分，世界大部分地区 1:53很快就会大麻烦。 1:54我们将不得不拿出一个非常巧妙的方法来种植粮食。 1:58而其中最需要的耐旱植物。

2:01另一件事是记住非洲， 2:04在他们的耕作大部分被雨水的支持。 2:08种植耐干旱的植物是不是最容易的事情。 2:11究其原因 - 水。 2:14水是生命的根本。 2:17所有生活，积极分子生物 2:21从微生物到你和我， 2:23它主要是由水组成。 2:25所有的生命反应发生在水中。 2:28低水分流失就意味着死亡。 2:31我和你是水65％ - 2:33失去了1个百分点 - 死 2:35但是，我们的行为可以改变，以避免它。 2:39植物不能。 2:41他们被困在地下。 2:43特别是，他们对我们更多的水 2:46约95％的水， 2:47他们可能会失去比我们多一点， 2:49从10至约70％，取决于物种， 2:54但只有很简单。 2:56大多数人会尽量避免或抵制水分流失。

3:00 Atsispiriančiųjų最显着的例子可以在肉质上找到。 3:04它们有体积小，非常有吸引力， 3:07但保持水分，以至于必须还清 3:10非常缓慢的增长速度。 3:13失水避免在树木和草丛被发现。 3:18他们花很长的根， 3:19产生底土水 3:21并始终使用这种水， 3:23它保持其湿度。 3:25右边的树叫做猴面包树。 3:27它也被称为倒树 3:29仅仅是因为树根和树枝的比例是这样的 3:33它甚至似乎棵树栽倒挂。 3:36当然，根是必需的植物保持水合。 3:40可能是最常见的策略是nepraradimo一年生植物。 3:45一年生植物占我们的蔬菜食品源的显著一部分。 3:49我国西海岸 3:50一年中的很大一部分，我们没有看到很多成长的绿色风景。 3:54但刚刚来到春雨，我们看到 3:57盛开的沙漠。 3:59战略等一年生植物

4:00它们只生长在雨季。 4:03本赛季结束时，他们是种子的果实， 4:06即干，8％-10％。水 4:09但正如热闹。 4:10一切都是这么干的，仍然活着， 4:13我们称之为干燥宽容。 4:15在干燥状态 4:17种子可以生存条件恶劣 4:19较长的时间跨度。 4:21下一次你在适当的时候下雨， 4:23它们发芽和生长， 4:25和整个周期再次开始。 4:28人们普遍认为，进化的干种子负责 4:32开花植物定植， 4:34或被子植物开花大地。 4:38但是，让我们回到同龄人，因为我们的主要食物来源。 4:42小麦，水稻，玉米约占95％。所有植物性食物资源。 4:48这是一个伟大的战略， 4:50因为很快你能长出很多种子。 4:53种子是丰富的能源，因此热量， 4:55能够存储的时候，有没有短缺或饥荒，

5:00但有一个反面。 5:02植物组织 5:03常年根和叶， 5:06的品质， 5:07这是由水，抗性或耐受性的丧失为特征。 5:11他们只是不需要这样。 5:12他们生长在雨季 5:14他们有一个种子，有助于生存今年余下时间。 5:17因此，尽管养殖统一的努力 5:20使植物更耐 5:23失水，干燥宽容， 5:25特别是，水的损失， 5:27因为我们有模式，以了解其运作， 5:30我们仍然获得这些图像。 5:32在非洲的玉米地， 5:33两个星期不下雨 5:35和所有遇难。 5:37有一个解决方案： 5:39复活植物。 5:41后者可能会失去95％。其细胞水， 5:45保持干燥，死国几个月甚至几年， 5:49和接收水 5:50他们进入叶开始生长。 5:53作为种子，他们是宽容的干燥。 5:56作为种子，它们能承受大自然的挑战。 6:01它是非常罕见的现象。 6:03只有135种开花植物，能做到这一点的。 6:08我会告诉你的视频， 6:09作为三种不同类型的复活 6:12的顺序。 6:13和底部 6:14有一个时间轴来了解这是如何快速发生。 6:56 （掌声）

7:02惊人的，是不是？ 7:03因此，我已了21年试图了解它是如何工作。 7:08当他们干要死了吗？ 7:11而我与许多不同的植物复兴工作 7:13如你所见，在干湿状态， 7:16出于某种原因。 7:17其中之一是，每个植物充当模型 7:20希望使耐旱植物。 7:23因此，左上角，例如，草， 7:26这就是所谓的画眉nindensis， 7:28她有一个近亲苔麸 - 7:30你们中许多人，它被称为画眉草 - 7:32这是埃塞俄比亚的主食， 7:34它不含麸质， 7:35这就是我们要耐旱的东西。 7:38另一个原因看一些其他的植物 7:41的是，至少在最初， 7:42我想知道他们是否在做同样的事情？ 7:44你用同样的方法， 7:46失去他们所有的水，死吗？ 7:49我做了所谓的系统生物学的方法 7:52我们有一个全面的了解 7:54到干燥性， 7:56在这里我们就来看看一切， 7:57从分子到整个植物生理生态水平。

8:00例如，我们看一下 8:02植物解剖学的变化，当他们干涸 8:04和超微结构。 8:05我们看transkriptomą，这是技术的名字， 8:09我们看着基因 8:10这是不上或响应于干。 8:12许多基因编码的蛋白质，所以看的蛋白质组。 8:16蛋白质有什么响应产生至干？ 8:19一些蛋白质编码形成代谢的酶， 8:23所以我们看metabolomą。 8:25因为植物被困在地球，这是很重要的。 8:28他们利用我所说的精心调校的化学武器库， 8:32为了保护自己免受环境问题。 8:35所以重要的是，一个看起来 8:37在干燥期间在工厂的化学变化。 8:40而在过去的调查显示，在分子水平上进行的， 8:43我们来看看lipidomą - 8:44血脂变化在干燥期间发生。 8:46这也很重要 8:47因为所有的生物膜是由脂类。 8:50它们作为膜，因为它们是在水中。 8:53减去水，膜落下。 8:56脂类也可以作为一个信号开启的基因。

9:00然后我们使用生理和生化研究 9:02试图了解假设受保护的功能 9:06谁发现了我们的其他研究。 9:09并用它都试图去理解， 9:11作为该植物是能够应付的自然环境。 9:15我一直以为我需要一个彻底干燥 9:19理解宽容机制， 9:22这样我就可以建立一个成功的提案，生物应用。 9:27你们中许多人现在在想， 9:28 “生物改编或 9:29这意味着，它会产生遗传修饰的植物？ 9:34回答这个问题是： 9:35它依赖于“转基因”的定义。 9:39所有的植物，我们吃，小麦，牧草，玉米 9:42我们强烈的基因从他们的祖先修改， 9:45但我们不会被视为他们的GM 9:47因为它们是由普通养殖生产的。 9:50我打算把基因复活到植物？ 9:54答案是肯定的。 9:56在他的时间，并尝试这种方法。 9:59具体而言，一些来自南非开普敦大学的同事，

10:02珍妮弗 - 汤普森，Suhail Rafudeen， 10:04他领导的那个方法。 10:05很快JUM数据显示。 10:09但很快我们将开始一个非常雄心勃勃的办法， 10:13我们希望把所有基因组， 10:16已经存在于每个植物。 10:19他们只是从来没有在猛烈的干旱条件下启用。 10:22我让你来决定， 10:24不管他们是否仍然被称为通用与否。 10:27我会给你一些数据从我们的第一个方法。 10:31而为了让他们明白， 10:32我要解释一下如何的基因。 10:35因此，所有的你可能知道， 10:36基因是由DNA组成。 10:38他们被密集扭曲成染色体， 10:40位于每个小区中，我们，以及植物细胞。 10:44如果缫丝DNA，我们收到的基因。 10:47与每个基因具有启动子， 10:50这简直就是开关按钮， 10:52基因编码区 10:54然后终止 10:55告诉它是基因的末端，另一种基因从这里开始。 10:59启动子是不是简单地接通 - 关按钮。

11:02他们往往需要大量的微调， 11:05激活基因以前很多必要的东西。 11:10那么，什么是生物技术研究典型的做法， 11:13我们使用诱导型启动子， 11:15我们知道如何打开它。 11:16我们把它们挂从感兴趣的基因 11:18并将它们放置在工厂，我们观察到，什么是响应。 11:22这项研究，其中的告诉你 11:24同事使用了一种干旱诱导启动子 11:27我们发现了一种令人振奋的植物。 11:29我们不需要做任何事情的启动子的很大一部分。 11:32植物本身的感觉旱情。 11:35而我们用在植物抗氧化基因的那ištrauktume。 11:40为什么抗氧化基因？ 11:42好了，所有的困难，特别是在干旱问题， 11:45引起自由基的产生， 11:48或活性氧菌， 11:50这严重损害了工厂，并因此他可能会死。 11:53抗氧化剂停止损害。 11:57这里是从玉米应变，这是在非洲特别受欢迎的一些信息。

12:01左侧目录是植物无基因 12:04正确的 - 12:05具有抗氧化基因植物。 12:07 3周停水后 12:09那些基因仍比没有该基因好得多。 12:13现在，最后一个方法。 12:15我搜索发现，有明确的机制 12:18宽容和恢复植物的干种子之间的相似性。 12:23于是几个问题 12:24是否使用相同的基因？ 12:26或稍转述， 12:28或者复活工厂使用已经从种子干燥产生耐受性基因， 12:33它的叶子和根？ 12:34难道他们给它的种子基因一份新工作 12:36复兴植物叶片和根？ 12:39我的回答是， 12:41作为我的广泛研究的结果 12:44在荷兰与江恒光Hihhorsto集团合作， 12:47梅尔奥利弗在英国 12:49和朱莉娅Buitnik法国。 12:51答案是肯定的， 12:53它负责为明亮组基因。 12:56并说明这种非常粗略玉米 12:59在停止按钮下方的染色体

13:02代表需要干燥容忍所有的基因。 13:05因此，当在其发展的最终玉米种子晒出来， 13:09他们开启这些基因。 13:12复活植物激活相同的基因， 13:15当他们干。 13:17每间现代化的作物，因为 13:19这些基因有各自的叶和根， 13:21只是他们从来没有打开它们。 13:22他们打开它们唯一的种子组织。 13:25我们试图尽现， 13:27这是理解环境和蜂窝信号， 13:29这开启参与振兴植物的基因 13:33恢复在植物的过程。 13:35而最后一个念头。 13:37我们试图提出一个非常快速的步伐， 13:39这是复制什么性质已经超过恢复植物的进化完成 13:43 10-40万年前。 13:46我的工厂和我感谢您的关注。 13:48 （掌声）