I believe that the secret to producing extremely drought-tolerant crops,
我认为培育十分耐旱的农作物，
which should go some way to providing food security in the world,
某种程度上可以保障世界粮食安全，
lies in resurrection plants, pictured here, in an extremely droughted state.
而其中的秘诀在于这张拍摄于一个非常干旱的州的图片中的复苏植物。
You might think that these plants look dead, but they're not.
你也许认为这些植物看起来已经死了，但其实它们没死。
Give them water, and they will resurrect, green up, start growing, in 12 to 48 hours.
如果给它们水，它们将会在12-48小时后复活，变绿，开始生长。
Now, why would I suggest that producing drought-tolerant crops will go towards providing food security?
现在，为什么我提议培育耐旱的农作物可以保障粮食安全呢？
Well, the current world population is around 7 billion.
当今世界人口大约为70亿。
And it's estimated that by 2050, we'll be between 9 and 10 billion people, with the bulk of this growth happening in Africa.
预计到2050年，人口将增长至90-100亿，这其中大部分的人口增长在非洲。
The food and agricultural organizations of the world have suggested
世界粮农组织建议，
that we need a 70 percent increase in current agricultural practice to meet that demand.
我们在现有基础上，需要将农业产量提高70%来满足那时的需求。
Given that plants are at the base of the food chain, most of that's going to have to come from plants.
因为植物是食物链的基础，所以增加的产量大部分需要来自植物。
That percentage of 70 percent does not take into consideration the potential effects of climate change.
但是70%的增量并没有考虑气候变化所带来的潜在影响。
This is taken from a study by Dai published in 2011,
这是戴在2011年发表的研究报告，
where he took into consideration all the potential effects of climate change and expressed them -- amongst other things
他考虑了气候变化带来的所有可能的影响，然后把它们展现出来，
increased aridity due to lack of rain or infrequent rain.
其中就有由降水缺乏或频率低所导致的干旱区域增加。
The areas in red shown here, are areas that until recently have been very successfully used for agriculture,
这里显示的红色区域，是到目前为止农业非常发达，
but cannot anymore because of lack of rainfall. This is the situation that's predicted to happen in 2050.
但因为缺少降水将来不能耕种的地区。这是预计将在2050年发生的状况。
Much of Africa, in fact, much of the world, is going to be in trouble.
非洲的大部分地区，实际上，全球的大部分地区，都将会陷入困境。
We're going to have to think of some very smart ways of producing food.
我们将不得不想出一些非常巧妙的方法来生产食物。
And preferably among them, some drought-tolerant crops.
在其中比较合适的方法是培育一些耐旱的作物。
The other thing to remember about Africa is that most of their agriculture is rainfed.
关于非洲，我们需要记住的另一件事是，他们的大部分农业主要靠雨水灌溉。
Now, making drought-tolerant crops is not the easiest thing in the world.
现在，培育抗旱作物并非易事。
And the reason for this is water. Water is essential to life on this planet.
其中的原因在于水。在这个星球上，水对于生命来说是必不可少的。
All living, actively metabolizing organisms, from microbes to you and I, are comprised predominately of water.
所有活着的、代谢旺盛的有机体，从微生物到你我，主要由水构成。
All life reactions happen in water. And loss of a small amount of water results in death.
所有维持生命所需的反应发生在水中。即使丧失少量的水也会导致死亡。
You and I are 65 percent water -- we lose one percent of that, we die.
人体65%由水构成，如果我们丧失其中1%的水，我们就会死。
But we can make behavioral changes to avoid that. Plants can't. They're stuck in the ground.
但是我们可以通过行为的改变，来避免那种情况发生。植物却不能。它们生长在地上。
And so in the first instance they have a little bit more water than us, about 95 percent water,
所以首先他们比我们含水量更多，大概95%是水分，
and they can lose a little bit more than us, like 10 to about 70 percent, depending on the species, but for short periods only.
它们也可以比我们多失去一些水，不同物种可以短时间内损失10%到70%的水分。
Most of them will either try to resist or avoid water loss.
大多数物种都会抵制或尽量避免失水。
So extreme examples of resistors can be found in succulents.
举一个抗失水者的极端例子：肉质植物。
They tend to be small, very attractive, but they hold onto their water at such great cost that they grow extremely slowly.
它们一般很小很漂亮，但是它们为了保持水分，不得不生长的十分缓慢。
Examples of avoidance of water loss are found in trees and shrubs.
避免失水的主要例子都是乔灌木。
They send down very deep roots, mine subterranean water supplies and just keep flushing it through them at all times, keeping themselves hydrated.
它们的根须深入地下，直至地下水资源，不停地吸取大量的地下水来保持水分。
The one on the right is called a baobab. It's also called the upside-down tree,
右边的植物叫做猴面包树。它也被人成为倒置的树。
simply because the proportion of roots to shoots is so great that it looks like the tree has been planted upside down.
因为根部与地上部分的比例实在是太夸张，以至于这棵树像是倒置的一样。
And of course the roots are required for hydration of that plant.
当然了为了保持水分，这样的根部是必须的。
And probably the most common strategy of avoidance is found in annuals.
也许一年生植物是最常使用避免失水策略的植物了。
Annuals make up the bulk of our plant food supplies.
一年生植物是我们主要的种植的食物来源。
Up the west coast of my country, for much of the year you don't see much vegetation growth.
在我的国家的西海岸，一年中的绝大部分时间我们看不到这些蔬菜的生长。
But come the spring rains, you get this: flowering of the desert.
但当春天雨季来临，你可以看到，沙漠之中花开遍地。
The strategy in annuals, is to grow only in the rainy season.
一年生植物的策略就是只在雨季生长。
At the end of that season they produce a seed, which is dry, eight to 10 percent water, but very much alive.
在雨季结束的时候，它们产生种子，种子很干燥，只含有8%到10%的水，但却生机勃勃。
And anything that is that dry and still alive, we call desiccation-tolerant.
这样在干燥环境下仍保持活性的性质叫做干燥耐受。
In the desiccated state, what seeds can do is lie in extremes of environment for prolonged periods of time.
在干燥的条件下，种子可以在如此极端环境下存活很长一段时间。
The next time the rainy season comes, they germinate and grow, and the whole cycle just starts again.
下次雨季来临时，它们马上发芽生长，如此循环往复。
It's widely believed that the evolution of desiccation-tolerant seeds
人们普遍认为，正是进化出这样干燥耐受的种子，
allowed the colonization and the radiation of flowering plants, or angiosperms, onto land.
才让开花植物和被子植物在陆地上的定植和传播成为可能。
But back to annuals as our major form of food supplies. Wheat, rice and maize form 95 percent of our plant food supplies.
回到作为主要食物来源的一年生植物。比如构成我们食物来源95%的小麦，水稻和玉米。
And it's been a great strategy because in a short space of time you can produce a lot of seed.
这看起来也是一个很好的策略，因为短时间内就可以生产大量的种子。
Seeds are energy-rich so there's a lot of food calories, you can store it in times of plenty for times of famine, but there's a downside.
种子富含可以被人体吸收的能量，所以你可以在食物充足的时候为饥荒做准备，但是也有不足之处。
The vegetative tissues, the roots and leaves of annuals,
这些植物的营养组织，根部和叶片，
do not have much by way of inherent resistance, avoidance or tolerance characteristics.
并没有什么抵抗干燥、避免干燥或者耐受干燥的特性。
They just don't need them. They grow in the rainy season and they've got a seed to help them survive the rest of the year.
因为它们根本不需要。它们本来就生长在雨季，而且已经生产了可以度过余下时间的种子。
And so despite concerted efforts in agriculture to make crops with improved properties of resistance, avoidance and tolerance
而且无论农业专家如何努力提升农作物的抵抗、避免和耐受干旱的能力，
particularly resistance and avoidance because we've had good models to understand how those work, we still get images like this.
尤其是抵抗和避免干旱的能力，尽管我们已经有了很好的模型来了解植物的运作模式，我们仍然只得到了这样的结果。
Maize crop in Africa, two weeks without rain and it's dead. There is a solution: resurrection plants.
非洲的玉米作物，在两周不下雨之后就死了。现在有一个方案，就是复苏植物。
These plants can lose 95 percent of their cellular water, remain in a dry, dead-like state for months to years,
这些植物可以失去95%的细胞水分，进入干燥的假死状态长达数月之久，
and give them water, they green up and start growing again.
只要给它们水，它们马上就可以变绿开始生长。
Like seeds, these are desiccation-tolerant. Like seeds, these can withstand extremes of environmental conditions.
像种子一样，它们拥有干燥耐受性，可以忍受极端的环境。
And this is a really rare phenomenon. There are only 135 flowering plant species that can do this.
这是非常罕见的现象。全世界只有135种开花植物可以做到。
I'm going to show you a video of the resurrection process of these three species in that order.
我将给各位放一段三种复苏植物复苏过程的视频。
And at the bottom, there's a time axis so you can see how quickly it happens.
在视频下方有一个时间轴，各位可以看到一切发生得多么迅速。
Pretty amazing, huh? So I've spent the last 21 years trying to understand how they do this.
很神奇，是吧？所以我用了21年时间研究它们是如何做到的。
How do these plants dry without dying?
这些植物如何做到干而不死？
And I work on a variety of different resurrection plants, shown here in the hydrated and dry states, for a number of reasons.
因为很多原因，我研究了图中不同的复苏植物在干燥和有水环境下的状态。
One of them is that each of these plants serves as a model for a crop that I'd like to make drought-tolerant.
其中一个原因是，每一种复苏植物都可以作为一种农作物的耐旱版本的模板。
So on the extreme top left, for example, is a grass, it's called Eragrostis nindensis,
比如左上角这种草，它叫做画眉虫草，是苔麸的近亲，
it's got a close relative called Eragrostis tef -- a lot of you might know it as "teff"
也就是很多人熟知的埃塞俄比亚画眉草，
it's a staple food in Ethiopia, it's gluten-free, and it's something we would like to make drought-tolerant.
它是埃塞俄比亚的主要作物，它不含谷蛋白，我们想开发耐旱版本的埃塞俄比亚画眉草。

The other reason for looking at a number of plants, is that, at least initially, I wanted to find out: do they do the same thing?
另一个我们研究其它各种各样的植物的原因是，至少我们希望从本质上了解，它们是在做同样的事情么？
Do they all use the same mechanisms to be able to lose all that water and not die?
它们可以做到失水而不死的内在机制是相同的么？
So I undertook what we call a systems biology approach in order to get a comprehensive understanding of desiccation tolerance,
所以我采用系统生物学方法，希望对植物的耐旱性有一个全面的了解，
in which we look at everything from the molecular to the whole plant, ecophysiological level.
该方法就是从分子层面到整体植株生理生态层面的整体研究。
For example we look at things like changes in the plant anatomy as they dried out and their ultrastructure. We look at the transcriptome,
比如，我们通过解剖，观察干枯的植物的变化和它们的亚显微结构。我们观察转录组如何应对干旱，
which is just a term for a technology in which we look at the genes that are switched on or off, in response to drying.
转录组是一个技术术语，意思是我们观察基因开关在应对干旱时是开启还是关闭。
Most genes will code for proteins, so we look at the proteome.
大部分基因会制造蛋白质，所以我们研究蛋白质组。
What are the proteins made in response to drying?
干旱来临时植物会制造什么蛋白质？
Some proteins would code for enzymes which make metabolites, so we look at the metabolome.
一些蛋白质会制造让植物新陈代谢的酶，所以我们研究代谢组。
Now, this is important because plants are stuck in the ground.
这很重要，因为植物都是固定在土地之上的。
They use what I call a highly tuned chemical arsenal to protect themselves from all the stresses of their environment.
它们利用所谓的高度协调的化工厂，保护它们不受外界环境的压力。
So it's important that we look at the chemical changes involved in drying.
所以研究这些因为干燥引起的化学变化也非常重要。
And at the last study that we do at the molecular level, we look at the lipidome -- the lipid changes in response to drying.
最后，我们在分子层面的研究中，研究了脂质体，脂质是如何变化的以应对干旱的。
And that's also important because all biological membranes are made of lipids.
这也很重要，因为所有的生物膜都是脂质的。
They're held as membranes because they're in water.
因为在水中，所以它们保持膜状。
Take away the water, those membranes fall apart. Lipids also act as signals to turn on genes.
而当脱离水之后，这些膜就会破碎。脂质同样是开启基因的信号。
Then we use physiological and biochemical studies
我们运用生理和生化研究方法，
to try and understand the function of the putative protectants that we've actually discovered in our other studies.
去尝试并了解我们已经在其他研究中发现的假定保护机制。
And then use all of that to try and understand how the plant copes with its natural environment.
通过所有的这些研究，来尝试理解植物是如何适应它周围的自然环境的。
I've always had the philosophy that I needed a comprehensive understanding of the mechanisms of desiccation tolerance
我的科学哲学是，我需要对耐旱性的机制有全面的理解
in order to make a meaningful suggestion for a biotic application.
才可以给出对于生物应用的有意义的建议。
I'm sure some of you are thinking, "By biotic application, does she mean she's going to make genetically modified crops?"
我确信有一些人在想，“她所说的生物应用是不是意味着转基因作物呢？”
And the answer to that question is: depends on your definition of genetic modification.
这个问题的答案是：取决于如何定义转基因。
All of the crops that we eat today, wheat, rice and maize, are highly genetically modified from their ancestors,
所有我们今天食用的作物，小麦，水稻和玉米，与祖先植株相比都是高度转基因的，
but we don't consider them GM because they're being produced by conventional breeding.
我们不认为它们是转基因作物，是因为它们一直是用传统方式培育的。
If you mean, am I going to put resurrection plant genes into crops, your answer is yes.
如果你问我是不是打算把复苏植物的基因植入作物中，我的回答是是的。
In the essence of time, we have tried that approach.
时间紧迫，我们已经尝试了这些手段。
More appropriately, some of my collaborators at UCT, Jennifer Thomson, Suhail Rafudeen,
准确地说，我在UCT的一些同事，珍妮弗·汤姆森，萨尔·拉夫德恩，
have spearheaded that approach and I'm going to show you some data soon.
已经先行进行了实验，一会我将展示部分资料。
But we're about to embark upon an extremely ambitious approach,
但是我们将要开展的是一项极具野心的工作，
in which we aim to turn on whole suites of genes that are already present in every crop.
我们的目标是启动已经存在于每棵植株中的整套基因。
They're just never turned on under extreme drought conditions.
它们只是还没有在极端干旱的环境下被激活。
I leave it up to you to decide whether those should be called GM or not.
我希望各位可以自行判断这种方式是否属于转基因。
I'm going to now just give you some of the data from that first approach.
我将展示第一阶段实验的部分资料。
And in order to do that I have to explain a little bit about how genes work.
在展示之前，我需要解释一下基因工作的原理。
So you probably all know that genes are made of double-stranded DNA.
也许大家都知道，基因是由双链结构的DNA组成的。
It's wound very tightly into chromosomes that are present in every cell of your body or in a plant's body.
它通过紧密的缠绕形成染色体，存在于每个人体或者植物的细胞之中。
If you unwind that DNA, you get genes.
如果把DNA解缠，你就会得到基因。
And each gene has a promoter, which is just an on-off switch, the gene coding region, and then a terminator,
每一个基因有一个启动子--即一个开关，基因转录区和终止子，
which indicates that this is the end of this gene, the next gene will start.
这意味着这一部分基因转录结束，下一个基因将要开始转录。
Now, promoters are not simple on-off switches.
启动子不像开关那么简单。
They normally require a lot of fine-tuning, lots of things to be present and correct before that gene is switched on.
它们往往需要大量微调，很多条件必须存在且正确，基因才会打开。
So what's typically done in biotech studies is that we use an inducible promoter, we know how to switch it on.
所以在生物技术研究中，我们通常使用诱导型启动子，我们知道如何开启它。
We couple that to genes of interest and put that into a plant and see how the plant responds.
我们将其与要研究的基因配对，并放入植物中，看该植物如何反应。
In the study that I'm going to talk to you about,
在我接下来展示的研究中，
my collaborators used a drought-induced promoter, which we discovered in a resurrection plant.
我的同事使用了在复苏植物中发现的干旱诱导蛋白启动子。
The nice thing about this promoter is that we do nothing. The plant itself senses drought.
这个启动子的优势在于不用外界手段。植物会自发感受干旱。
And we've used it to drive antioxidant genes from resurrection plants. Why antioxidant genes?
我们使用启动子驱动复苏植物的抗氧化剂基因。为什么是抗氧化剂基因？
Well, all stresses, particularly drought stress, results in the formation of free radicals, or reactive oxygen species,
所有的压力，尤其是干旱的压力，都会形成自由基，也就是活性氧，
which are highly damaging and can cause crop death. What antioxidants do is stop that damage.
活性氧极具破坏力，会直接导致植物死亡。抗氧化剂可以阻止这种破坏。
So here's some data from a maize strain that's very popularly used in Africa.
现在看到的是某种玉米品系的数据，这在非洲极常使用。
To the left of the arrow are plants without the genes, to the right -- plants with the antioxidant genes.
箭头左边的是没有这种基因的，右边的是含有抗氧化基因的植株。
After three weeks without watering, the ones with the genes do a hell of a lot better.
三周没有浇水之后，有抗氧化基因的植株的状态要好得多。
Now to the final approach.
最后一点。
My research has shown that there's considerable similarity in the mechanisms of desiccation tolerance in seeds and resurrection plants.
我的研究已经表明，种子和复苏植物的耐旱性的机制有很多相似之处。
So I ask the question, are they using the same genes?
我的问题是，他们是同一种基因么？
Or slightly differently phrased, are resurrection plants using genes evolved in seed desiccation tolerance in their roots and leaves?
或用略为不同的问法，复苏植物在根部和叶部上也含有这种耐旱基因么？
Have they retasked these seed genes in roots and leaves of resurrection plants?
它们会把这些基因在根部和叶部重新使用么？
And I answer that question, as a consequence of a lot of research from my group
我可以回答这个问题，通过我和我的同事的小组的工作，
and recent collaborations from a group of Henk Hilhorst in the Netherlands, Mel Oliver in the United States and Julia Buitink in France.
通过来自荷兰的亨克·希尔霍斯特，来自美国的梅尔·奥利弗和来自法国的朱莉娅布克的一系列工作。
The answer is yes, that there is a core set of genes that are involved in both.
我们认为答案是：是的，它们都有一套完整的核心基因。
And I'm going to illustrate this very crudely for maize,
我用这张图跟大家粗略说一下玉米的情况，
where the chromosomes below the off switch represent all the genes that are required for desiccation tolerance.
在开关下面的染色体里面有耐旱性必要的全部基因。
So as maize seeds dried out at the end of their period of development, they switch these genes on.
当玉米种子在它们发育的最后一个阶段面临干燥环境时，就会打开这些基因。
Resurrection plants switch on the same genes when they dry out.
复苏植物遇到干旱环境是也会打开同样的基因。
All modern crops, therefore, have these genes in their roots and leaves, they just never switch them on.
因此所有现代的植物都在它们的根部和叶部拥有这些基因，只不过它们从来没有打开过。
They only switch them on in seed tissues. So what we're trying to do right now
它们仅打开种子组织内的这种基因。我们现在尝试要做的，
is to understand the environmental and cellular signals that switch on these genes in resurrection plants, to mimic the process in crops.
就是了解打开复苏植物基因开关的环境信号和细胞信号，并在作物中模仿类似的过程。
And just a final thought.
最后一点想法。
What we're trying to do very rapidly is to repeat what nature did in the evolution of resurrection plants some 10 to 40 million years ago.
我们现在做的就是，用飞快的速度重现一千到四千万年前大自然在复苏植物演化的过程中所做的。
My plants and I thank you for your attention.
我的植物和我都感谢您的关注。