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

譯者: C Leung 審譯者: 麗玲 辛

Today, nearly one in 10 is food insufficient.

如今，近十分之一的人糧食不足。

That number has been rising every year since 2014,

自 2014 年以來， 這數字每年都在上升，

and it's forecast to become considerably worse

並預計在未來兩到三十年裡，

over the next two to three decades.

這數字將變得更加糟糕。

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

對於非洲和亞洲較貧窮的 國家來說尤其如此，

where the rise in demand

這些國家的需求增長

is outpacing the rise in our ability to supply.

超過了我們供應能力的增長。

I want to tell you how the most important process

我想告訴你，增強光合作用，

on the planet,

boosting that process, photosynthesis,

這個地球上最重要的過程，

如何能緩解這個問題。

could alleviate this problem.

How photosynthesis works

光合作用的工作原理

is that plants remove carbon dioxide from the atmosphere,

是植物從大氣中去除二氧化碳，

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

然後利用太陽光的能量 將其轉化為我們的食物，

releasing our oxygen at the same time.

同時釋放氧氣給我們。

Photosynthesis is the most studied of all plant processes,

光合作用是所有植物過程中 被研究最多，

and from that knowledge,

從這些知識中，

we realize that even our most productive crops

我們意識到， 即使是產量最高的農作物，

are only achieving about one fifth

也只能實現該過程 潛在效率的五分之一左右。

of the potential efficiency of that process.

As the most studied of plant processes,

作為研究最多的植物過程，

we realize that the efficiency is low.

我們意識到它的低效率。

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

如果我們看看植物的其他基因改良，

these have typically involved one or two genes,

這些通常涉及一兩個基因，

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

例如，縮短水稻和小麥的莖，

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

使更多的植物生物量， 進入我們收穫的穀物中，

was at the core of the Green Revolution.

就是綠色革命的核心。

That involved mutations in just a few genes.

這僅僅涉及幾個基因突變。

But photosynthesis is a process of over 100 steps,

但光合作用是一種 有 100 多個步驟的過程，

each of these facilitated by a different protein

每個步驟都由不同的蛋白質促進，

and in turn coded for by many genes.

並由許多基因編碼。

So where do you start?

那麼你會從哪裡開始？

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

你可以把它想像成一條汽車生產線。

Imagine you've got a thousand workers.

想像下你有一千名工人。

Where do you place them on your line

你會將他們放在生產線上的哪個位置

to get the most output?

以獲得最大的產出？

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

同樣，如果你考慮到 葉子中的蛋白質含量，

how do you distribute that between all these steps

你會如何在這些步驟中分配它們

to get the maximum efficiency?

以獲得最大效率？

If you could work that out,

如果你能解決這個問題，

then maybe you could make progress.

也許你就能取得進展。

However, to do this experimentally with all these permutations

然而，用所有這些排列進行實驗

may take decades.

或需幾十年時間。

So instead, we built a digital twin of the process

因此，我們改而建立了 該過程的數位雙胞胎，

in which every one of these reactions

其中每個反應

was described by a differential equation

都由微分方程去描述，

producing a system that we could then numerically integrate and optimize

產生一個系統，然後我們可以 對該系統進行數值積分和最佳化，

to pick out where should we be making changes.

以找出我們應該在哪裡進行更改。

So after three years of building this system,

經過三年的建立系統，

we are now ready to do our numerical integration.

我們現在已準備好進行數值積分。

And it failed.

但它失敗了。

It failed miserably.

一敗塗地。

(Laughter)

（笑聲）

Fortunately, another scientist at our computer center

幸運地，我們電腦中心的另一位科學家

heard us talking about our problems

聽到我們正談論的問題，並說：

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

「哦，我在平衡火箭發動機的工作中

on balancing rocket motors,

遇到了完全相同的問題，

and here's how I solved it."

我就是這樣解決的。」

So he looked at our problem and he said,

他看了我們的問題，然後說：

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

「哦，這比我正在做的更具挑戰性。」

And he worked with us.

後來他和我們一起工作。

And using his methods,

使用他的方法，

we were now able to numerically integrate our system,

我們現在能夠對系統進行數位積分，

and we could optimize that,

我們可以對其進行最佳化，

and we could start to see places

並且可以開始尋找

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

我只是想告訴你，

that photosynthesis isn't rocket science.

光合作用不是火箭科學。

It's harder.

它更加難。

(Laughter)

（笑聲）

(Applause)

（掌聲）

Well, of course, models can look very attractive.

毫無疑問，模特兒看起來很有吸引力。

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

但當你必須進入泥濘的農田

to show that you can actually do this,

來證明你真的可以做到這點時，

it doesn't look quite so pretty.

它看起來就不那麼漂亮了。

But despite these challenges,

儘管面臨這些挑戰，

we were able to get together a team of experts

但我們還是聚集了

from Australia, Britain, China and the United States

來自澳洲、英國、 中國和美國的專家團隊，

to work together on this.

共同致力解決這個問題。

And this is how we work.

這就是我們的工作方式。

We use this digital twin to say, well,

我們用這個數位雙胞胎來看，

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

我們可能作出最容易， 而產生重大影響的改變是什麼？

Then we engineer that into a crop.

然後我們將其改進到農作物去。

If in the greenhouse,

如果在溫室裡，

we can see that the genetically modified plant is yielding more

我們可以看到基因改造植物的產量

than the unmodified one,

比未基因改造植物的為高，

then we have the acid test saying,

然後我們進行真正的考驗，

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

看看這真的能為 我們的實驗農場提高產量嗎？

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

現在，我們對光合作用 進行了三種不同改變，

each individually increasing yield by over 20 percent.

每一種都將產量 提高了 20% 以上。

And I'll just tell you about --

我只想告訴你們－

(Applause)

（掌聲）

A couple of these in a little more detail.

其中的幾個更詳細內容。

In one case, the digital twin said

在一個案例中，數位雙胞胎顯示，

a protein we call SBPase

葉子中一種 我們稱為 SBPase 的蛋白質

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

應該比實際含量豐富得多。

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

因此，我們加入了額外的基因副本 來編碼那種蛋白質。

We made more of it, we got more photosynthesis,

製造了更多蛋白質， 產生了更多光合作用，

we got a higher yield.

並獲得更高產量。

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

這有點難以理解，因為......

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

這種蛋白質只佔 葉子總蛋白質的一小部分，

So why hadn’t evolution already done this?

那為什麼進化還沒做到這點呢？

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

一位同事向我們指出，

原始農作物是在二氧化碳濃度

evolved in the carbon dioxide concentration

that is about half what it is today.

約為今天一半的情況下進化而來的。

Aha!

啊哈！

So we reran the model at this past CO2 concentration,

因此，我們以過去的 二氧化碳濃度下重新運行模型，

and we found now that the model was saying

發現該模型表明

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

你不再需要這種蛋白質了。

So then we got curious, what about the future?

然後我們很好奇，未來會怎樣？

In 2050, we're predicting

我們預計 2050 年

a considerably higher carbon dioxide concentration.

二氧化碳濃度將顯著增加。

When we ran it at that higher concentration,

當我們以更高的濃度運行時，

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

它顯示增加這種蛋白質的 好處甚至更大。

Well, we couldn't easily remove carbon dioxide

我們無法輕易地從農作物周圍 的空氣中去除二氧化碳，

from the air around our crop,

but we could add it.

但我們可以添加它。

And when we did this,

當我們這樣做，

the model prediction was proved that we did indeed get

模型預測證明我們產量 確實獲得了更大的提升。

an even bigger boost in yield.

So this told us that evolution has just not had time

所以這告訴我們，進化只是還來不及

to keep pace with the changes we have made

跟上我們對農作物環境所做的改變。

in crop environments.

Now, another change we've made in crop environments

我們對農作物環境所做的另一個改變，

is to grow our crops at ever-increasing densities.

是以不斷增加密度去種植農作物。

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

這意味著在農作物範圍內有很多陰影。

So over the course of a day,

因此，在一天裡，

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

由於雲層、太陽穿過天空， 葉子會進出陰影，

due to the passage of the sun across the sky,

but most importantly,

但最重要的是，

shadows cast by other leaves.

還有其他葉子的陰影。

Now, for photosynthesis,

對於光合作用，

when the leaf goes into the shade,

當葉子進入陰影時，

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

就像你從陽光下離開，

going into the shade of a room,

進入房間的陰暗處，

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

你的眼睛需要時間來適應這種變化。

The same is true of photosynthesis,

光合作用也是這樣，

except it adjusts rather more slowly than your eyes.

只是它的調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.

這種緩慢的調整估計會導致 生產力下降 20% 到 40% 。

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

因此，我們再次利用 數位雙胞胎和其他訊息，

we identified three proteins that we should regulate.

確定了我們應該調節的三種蛋白質。

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

我們添加了這些蛋白質的 額外基因副本，

got more of them,

獲得了更多蛋白質，

the leaves adapted faster to fluctuations in light.

葉子更快地適應了光線的波動。

And in soybean on our farm

在我們農場種植的大豆，

we got more than 20 percent increase in seed yield.

種子產量增加了 20% 以上。

(Applause)

（掌聲）

So how do we now get from these improvements

那麼，我們現在如何從這些改進中

to seed

獲得種子，

which will give greater yields where it is most needed?

從而在最需要的地方提高產量呢？

And I'll just give you one ongoing example.

我給你一個現正進行的例子。

We've been working with TJ Higgins,

我們一直和 TJ 希金 (TJ Higgins) 合作，

a plant biotechnologist from Australia,

他是來自澳洲的植物生物技術專家，

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

在尼日利亞工作了近 20 年，

developing insect-resistant cowpea.

致力於開發抗蟲豇豆。

Cowpea is probably not what you think it is.

豇豆可能不是你想像的那樣。

Cowpea is actually a nitrogen-fixing crop

豇豆實際上是一種固氮農作物， 與大豆有親緣關係，

related to soybean,

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

它像大豆一樣產生富含蛋白質的種子。

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

事實上，它是西非最重要的 植物性蛋白質來源，

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

通常被稱為「廉價肉」。

A problem with cowpea is that a pod boring insect

豇豆的一個問題是，一種蛀莢蟲，

can completely destroy a family's entire crop.

可以完全摧毀一個家庭的全部農作物。

So TJ's ...

所以 TJ 的......

genetically modified cowpea that is insect-resistant

抗蟲基因改造的豇豆

is very powerful,

非常強大，

and TJ and his colleagues work with governments in West Africa

TJ 和他的同事 與西非各國政府合作，

to put in place regulatory frameworks for genetically modified crops.

為基因改造農作物製定了監管框架 。

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

如今，這種抗蟲豇豆 已可供尼日利亞農民使用，

where it's become very popular.

並且非常受歡迎。

This year, it was also released in Ghana.

今年，它也在加納推出。

So what we are now doing with TJ

所以我們現在對 TJ 所做的，

is stacking our photosynthetic improvements

就是疊加我們的改良光合作用

on top of his insect resistance --

到他的抗蟲技術基礎之上。

this is all royalty-free --

這都是沒有專利的，

so that these farmers will have access to seed,

這樣農民就可以獲得種子，

which will produce a crop which is insect-resistant

從而生產出抗蟲農作物，

and delivers a higher yield.

並提高產量。

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

我希望我已經向你展示了......

by boosting photosynthesis

透過促進光合作用，

we can relieve the risk of food insufficiency

我們可以減輕一些

最弱勢族群的糧食不足風險。

for some of the most vulnerable.

We can protect the environment

我們可以

by preventing the need to go onto yet more land

透過防止增加更多土地 去生產食物，來保護環境。

to produce our food.

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

我們甚至有可能從大氣中

去除二氧化碳。

from the atmosphere.

A 21-century Green Revolution,

我們迫切需要， 一場 21 世紀的綠色革命。

one we so urgently need.

Thank you.

謝謝。

(Applause)

（掌聲）