Can We Hack Photosynthesis to Feed the World? | Steve Long | TED

翻译人员: Leyu Jiang 校对人员: suya f.

Today, nearly one in 10 is food insufficient.

如今，几乎十分之一的人口 处于食物不足的状态。

That number has been rising every year since 2014,

而自 2014 年以来， 这个数字每年都在上升，

and it's forecast to become considerably worse

并且预计在接下来的二到三十年中

over the next two to three decades.

这一数字将变得相当糟糕。

This is especially true for the poorer countries of Africa and Asia,

对于较贫穷的非洲和 亚洲国家来说尤其如此，

where the rise in demand

那里的对粮食的需求

is outpacing the rise in our ability to supply.

的增长速度已经超过了 我们供应能力的增长。

I want to tell you how the most important process

我想告诉你这个星球

on the planet,

上最重要的促进这一状态的过程，

boosting that process, photosynthesis,

即光合作用，

could alleviate this problem.

可以如何缓解这个问题。

How photosynthesis works

光合作用的工作原理

is that plants remove carbon dioxide from the atmosphere,

是植物从大气中去除二氧化碳，

then they use sunlight energy to convert that into our food,

然后利用阳光能量。 将其转化为我们的食物，

releasing our oxygen at the same time.

同时释放我们的氧气。

Photosynthesis is the most studied of all plant processes,

光合作用是在所有植物经历的 化学过程中研究最多的过程，

and from that knowledge,

而从这些知识中，

we realize that even our most productive crops

我们意识到，

are only achieving about one fifth

即使是我们生产力最高的作物 也只能达到该过程潜在效率

of the potential efficiency of that process.

的五分之一左右。

As the most studied of plant processes,

作为研究最多的种植工艺，

we realize that the efficiency is low.

这让我们意识到这个效率很低。

Now, if we look at other genetic improvements of plants,

现在，如果我们看 其他植物的其他基因改良，

these have typically involved one or two genes,

这些改良通常涉及一两个基因，

for example, the shortening of the stems of rice and wheat,

例如，缩短水稻和小麦的茎，

allowing more of the plant's biomass to go into the grain that we harvest,

让更多的植物的生物量 进入我们收获的谷物中，

was at the core of the Green Revolution.

这就是是绿色革命的核心。

That involved mutations in just a few genes.

这仅涉及几个基因的突变。

But photosynthesis is a process of over 100 steps,

但是光合作用是一个 超过 100 个步骤的过程，

each of these facilitated by a different protein

每个步骤都由不同的蛋白质协助，

and in turn coded for by many genes.

然后由许多基因编码。

So where do you start?

那么从哪里开始呢？

Well, you can envisage this like a car production line.

好吧，你可以把它想象成汽车生产线。

Imagine you've got a thousand workers.

想象一下你有一千名员工。

Where do you place them on your line

你把它们放在你的生产线上的哪个位置

to get the most output?

可以获得最大的产出？

Similarly, if you consider the amount of protein in a leaf,

同样的，如果你考虑 叶子中的蛋白质含量，

how do you distribute that between all these steps

你如何在所有这些步骤 之间分配这些蛋白质含量，

to get the maximum efficiency?

以获得最大效率？

If you could work that out,

如果你能解决这个问题，

then maybe you could make progress.

那么也许你可以取得进展。

However, to do this experimentally with all these permutations

但是，对所有这些排列进行实验

may take decades.

可能需要几十年的时间。

So instead, we built a digital twin of the process

因此，取而代之的是， 我们建立了一个处理过程

in which every one of these reactions

其中每一个反应

was described by a differential equation

都由微分方程来描述，

producing a system that we could then numerically integrate and optimize

从而生成一个系统，然后我们 可以对该系统进行数值整合和优化，

to pick out where should we be making changes.

以确定我们应该在哪里进行更改。

So after three years of building this system,

因此，在构建这个系统三年之后，

we are now ready to do our numerical integration.

我们现在已经准备好进行数值积分了。

And it failed.

但它失败了。

It failed miserably.

它，惨遭失败。

(Laughter)

（笑声）

Fortunately, another scientist at our computer center

幸运的是，我们计算机 中心的另一位科学家

heard us talking about our problems

听到我们在谈论我们的问题

and said, "Oh, I had exactly the same problem with my work

并说：“哦，我在平衡火箭发动机的工作

on balancing rocket motors,

中遇到了完全相同的问题，

and here's how I solved it."

我是这样解决的。”

So he looked at our problem and he said,

于是他看了我们的问题，他说：

"Oh, this is more challenging than what I'm doing."

“哦，这比我正在做 的事情更具挑战性。”

And he worked with us.

于是他和我们一起工作。

And using his methods,

使用他的方法，

we were now able to numerically integrate our system,

我们现在能够对系统进行数值整合，

and we could optimize that,

我们可以对其进行优化，

and we could start to see places

然后我们可以开始寻找

where we might be able to improve photosynthesis.

可以改善光合作用的地方。

So that's just to tell you

因此，这只是为了告诉你

that photosynthesis isn't rocket science.

，光合作用不是火箭科学。

It's harder.

这更难。

(Laughter)

（笑声）

(Applause)

（掌声）

Well, of course, models can look very attractive.

嗯，当然，这些模型看起来很吸引人。

But when you now have to go into a muddy crop field

但是，当你现在必须进入泥泞的农田

to show that you can actually do this,

来证明你真的可以做到这一点时，

it doesn't look quite so pretty.

它看起来并不那么漂亮。

But despite these challenges,

但是，尽管面临这些挑战，

we were able to get together a team of experts

我们还是能够召集

from Australia, Britain, China and the United States

来自澳大利亚、英国、 中国和美国的专家团队

to work together on this.

共同努力解决这个问题。

And this is how we work.

这就是我们的工作方式。

We use this digital twin to say, well,

我们用这个数字对来说，好吧，

what is the easiest change we might make that would have a big impact?

我们可能做出的最容易 产生重大影响的改变是什么？

Then we engineer that into a crop.

然后我们把它改造成作物。

If in the greenhouse,

如果在温室里，

we can see that the genetically modified plant is yielding more

我们可以看到转基 因植物的产量

than the unmodified one,

高于未转基因植物，

then we have the acid test saying,

那么我们的酸性测试表明，

does this actually provide a higher yield on our experimental farm?

这真的为我们的实验农场 提供了更高的产量吗？

Now we've now made three different changes to photosynthesis,

现在，我们已经对光合作用 进行了三种不同的改变，

each individually increasing yield by over 20 percent.

每种变化分别使产量 提高了 20％ 以上。

And I'll just tell you about --

我只想告诉你——

(Applause)

（掌声）

A couple of these in a little more detail.

我会更详细地介绍其中的几个。

In one case, the digital twin said

在一个案例中，数据对显示了一个

a protein we call SBPase

我们称之为为 SBPase 的蛋白质

should be far more abundant in the leaf than it is.

在叶片中的含量应该比现在高得多。

So we put in extra copies of the genes coding for that protein.

因此，我们添加了编码 该蛋白质的基因的额外副本。

We made more of it, we got more photosynthesis,

我们用它做得更多，光合作用更多，

we got a higher yield.

我们得到了更多的产量。

Well, this was a bit of a mystery because ...

好吧，这有点神秘，因为...

This protein is a tiny fraction of the leaf's total protein.

这种蛋白质只占 叶子总蛋白质的一小部分。

So why hadn’t evolution already done this?

那么，为什么进化还没有做到这一点呢？

A colleague pointed out to us that the ancestors of our crops

一位同事向我们指出，我们作物的祖先是

evolved in the carbon dioxide concentration

在二氧化碳浓度的一半的环境下

that is about half what it is today.

进化而来的。

Aha!

啊哈！

So we reran the model at this past CO2 concentration,

所以我们以过去的二氧化碳浓度 重新运行了模型，

and we found now that the model was saying

现在我们发现模型显示

well you don't need any more of this protein.

我们不再需要这种蛋白质了。

So then we got curious, what about the future?

然后我们开始好奇，未来呢？

In 2050, we're predicting

我们预计到 2050 年，

a considerably higher carbon dioxide concentration.

二氧化碳浓度将大大提高。

When we ran it at that higher concentration,

当我们以更高的浓度运行时，

it said the benefit of increasing this protein was even greater.

增加这种蛋白质的好处甚至更大。

Well, we couldn't easily remove carbon dioxide

好吧，我们无法轻易地

from the air around our crop,

从作物周围的空气中去除二氧化碳，

but we could add it.

但我们可以添加二氧化碳。

And when we did this,

当我们这样做时。

the model prediction was proved that we did indeed get

模型预测被证明我们的产量确实得到了

an even bigger boost in yield.

一个更大的提升。

So this told us that evolution has just not had time

因此，这告诉我们，进化没有时间

to keep pace with the changes we have made

去跟上我们在作物环境

in crop environments.

中所做的变化。

Now, another change we've made in crop environments

现在，我们在作物环境 方面所做的另一项改变

is to grow our crops at ever-increasing densities.

是以不断增加的密度种植作物。

This means that there's a lot of shading within the crop.

这意味着作物中有很多阴影。

So over the course of a day,

因此，在一天中，

the leaves are going in and out of shade due to clouds,

由于云层，由于太阳穿过天空，

due to the passage of the sun across the sky,

树叶在阴凉处进进出出。

but most importantly,

但最重要的，

shadows cast by other leaves.

是其他树叶投下来的阴影。

Now, for photosynthesis,

现在，对于光合作用，

when the leaf goes into the shade,

当树叶进入阴凉处时，

it's rather like you coming out of the sunshine,

就像你走出阳光，

going into the shade of a room,

进入房间的阴凉处，

and it takes time for your eyes to adjust to that change.

你的眼睛需要时间来适应这种变化。

The same is true of photosynthesis,

光合作用也是如此，

except it adjusts rather more slowly than your eyes.

只是它的调整速度比你的眼睛慢得多。

Over the course of the day,

在一天中，

this slow adjustment costs productivity an estimated 20 to 40 percent.

这种缓慢的调整估计会 使生产率降低 20％ 至 40％ 。

So again, using our digital twin and also other information,

因此，再一次，利用 我们的数字对和其他信息，

we identified three proteins that we should regulate.

我们确定了应该调节的三种蛋白质。

So we added extra copies of the genes for those proteins,

因此，我们为这些 蛋白质添加了额外的基因拷贝，

got more of them,

获得了更多的基因，

the leaves adapted faster to fluctuations in light.

叶片更快地适应了光线的波动。

And in soybean on our farm

在我们农场种植的大豆，

we got more than 20 percent increase in seed yield.

我们的种子产量提高了 20％ 以上。

(Applause)

（掌声）

So how do we now get from these improvements

那么，我们现在如何从这些改进中

to seed

获得种子，

which will give greater yields where it is most needed?

而在最需要的地方提高产量？

And I'll just give you one ongoing example.

我只给你举一个现在还在持续的例子。

We've been working with TJ Higgins,

我们一直在与来自澳大利亚的

a plant biotechnologist from Australia,

植物生物技术专家 TJ希金斯（TJ Higgins）合作，

who's been working in Nigeria really for almost 20 years,

他在尼日利亚工作了将近 20 年

developing insect-resistant cowpea.

正在开发抗虫的鞘豆。

Cowpea is probably not what you think it is.

豇豆可能不是你想象的那样。

Cowpea is actually a nitrogen-fixing crop

豇豆实际上是一种与大豆

related to soybean,

相关的固氮作物，

and it produces, like soybean, a protein-rich seed.

它像大豆一样会产生富含蛋白质的种子。

It is, in fact the most important vegetable protein source in West Africa,

实际上，它是西非 最重要的植物蛋白来源。

and it is often referred to as the “poor man’s meat.”

通常被称为 “穷人的肉”。

A problem with cowpea is that a pod boring insect

豇豆的一个问题是， 一只枯萎豆荚的昆虫

can completely destroy a family's entire crop.

可以完全摧毁一个家庭的全部农作物。

So TJ's ...

所以 TJ 的...

genetically modified cowpea that is insect-resistant

具有抗虫性的转基因鞘豆

is very powerful,

非常强大，

and TJ and his colleagues work with governments in West Africa

TJ和他的同事与西非政府合作，

to put in place regulatory frameworks for genetically modified crops.

为转基因作物制定了监管框架。

And now this insect-resistant cowpea is available to farmers in Nigeria,

现在，这种抗虫的鞘豆 可供尼日利亚的农民使用，

where it's become very popular.

在那里它已变得非常受欢迎。

This year, it was also released in Ghana.

今年，它也在加纳发行。

So what we are now doing with TJ

因此，我们现在对TJ所做的

is stacking our photosynthetic improvements

是在他的抗虫能力的基础上再加

on top of his insect resistance --

上我们对光合作用的改进——

this is all royalty-free --

这都是免版税的——

so that these farmers will have access to seed,

这样这些农民就能获得种子，

which will produce a crop which is insect-resistant

从而生产出具有抗虫性

and delivers a higher yield.

产量更高的作物。

So I hope I've shown to you that ...

所以我希望我已经向你展示了...

by boosting photosynthesis

通过促进光合作用，

we can relieve the risk of food insufficiency

我们可以减轻一些最弱势食物不足的群体

for some of the most vulnerable.

易受伤害的风险。

We can protect the environment

我们可以通过防止

by preventing the need to go onto yet more land

需要在更多的土地上生产食物

to produce our food.

来保护环境。

And the possibility that we might even be able to remove carbon dioxide

而且我们甚至有可能

from the atmosphere.

从大气中去除二氧化碳。

A 21-century Green Revolution,

一场 21 世纪的绿色革命，

one we so urgently need.

我们迫切需要这场革命。

Thank you.

谢谢大家。

(Applause)

（掌声）