9:59:59.000,9:59:59.000
I believe that the secret to producing[br]extremely drought tolerant crops,

9:59:59.000,9:59:59.000
which should go some way[br]to providing food security in the world,

9:59:59.000,9:59:59.000
lies in Resurrection plants,

9:59:59.000,9:59:59.000
pictured here, in an extremely[br]droughted state.

9:59:59.000,9:59:59.000
Now you might think[br]that these plants look dead,

9:59:59.000,9:59:59.000
but they're not.

9:59:59.000,9:59:59.000
Give them water,

9:59:59.000,9:59:59.000
and they will resurrect, green up,[br]start growing,

9:59:59.000,9:59:59.000
in 12 to 48 hours.

9:59:59.000,9:59:59.000
No why would I suggest

9:59:59.000,9:59:59.000
that producing drought tolerant crops[br]will go towards providing food security?

9:59:59.000,9:59:59.000
Well the current world population[br]is around 7 billion.

9:59:59.000,9:59:59.000
And it's estimated that by 2050,

9:59:59.000,9:59:59.000
we'll be between 9 and 10 billion people,

9:59:59.000,9:59:59.000
with the bulk of this growth[br]happening in Africa.

9:59:59.000,9:59:59.000
The food and agricultural[br]organizations of the world

9:59:59.000,9:59:59.000
have suggested that we need a 70 percent[br]increase in current agricultural practice

9:59:59.000,9:59:59.000
to meet that demand.

9:59:59.000,9:59:59.000
Now given that plants[br]are at the base of the food chain,

9:59:59.000,9:59:59.000
most of that's going[br]to have to come from plants.

9:59:59.000,9:59:59.000
Now that percentage of 70 percent

9:59:59.000,9:59:59.000
does not take into consideration[br]the potential effects of climate change.

9:59:59.000,9:59:59.000
This is taken from a study by Dye[br]published in 2011,

9:59:59.000,9:59:59.000
where he took into consideration[br]

9:59:59.000,9:59:59.000
all the potential effects[br]of climate change

9:59:59.000,9:59:59.000
and expressed them[br]amongst other things,

9:59:59.000,9:59:59.000
increased aridity due to lack or rain[br]or infrequent rain.

9:59:59.000,9:59:59.000
Now the areas in red shown here,

9:59:59.000,9:59:59.000
are areas that until recently, have been[br]very successfully used for agriculture,

9:59:59.000,9:59:59.000
but cannot anymore[br]because of lack of rain fall.

9:59:59.000,9:59:59.000
This is the situation[br]that's predicted to happen in 2050.

9:59:59.000,9:59:59.000
Much of Africa,

9:59:59.000,9:59:59.000
in fact much of the world,

9:59:59.000,9:59:59.000
is going to be in trouble.

9:59:59.000,9:59:59.000
We're going to have to think of some[br]very smart ways of producing food.

9:59:59.000,9:59:59.000
And preferably among them,[br]some drought-tolerant crops.

9:59:59.000,9:59:59.000
The other thing to remember about Africa

9:59:59.000,9:59:59.000
is that most of the[br]agriculture is rain fed.

9:59:59.000,9:59:59.000
Now making drought-tolerant crops[br]is not the easiest thing in the world.

9:59:59.000,9:59:59.000
And the reason for this is water.

9:59:59.000,9:59:59.000
Water is essential to life on this planet.

9:59:59.000,9:59:59.000
All living, actively[br]metabolizing organisms,

9:59:59.000,9:59:59.000
from microbes to you and I,

9:59:59.000,9:59:59.000
are comprised predominately of water,[br]

9:59:59.000,9:59:59.000
all life reactions happen in water,

9:59:59.000,9:59:59.000
and loss of a small amount[br]of water results in death.

9:59:59.000,9:59:59.000
You and I are 65 percent water,

9:59:59.000,9:59:59.000
we lose one percent of that, we die.

9:59:59.000,9:59:59.000
But we can make behavioral[br]changes to avoid that.

9:59:59.000,9:59:59.000
Plants can't.

9:59:59.000,9:59:59.000
They're stuck in the ground.

9:59:59.000,9:59:59.000
So in the first instance, they have[br]a little bit more water than us,

9:59:59.000,9:59:59.000
about 95 percent water,

9:59:59.000,9:59:59.000
and they can lose[br]a little bit more than us,

9:59:59.000,9:59:59.000
like 10 to about 70 percent,[br]depending on the species,

9:59:59.000,9:59:59.000
but for short periods only.

9:59:59.000,9:59:59.000
Most of them will either try to resist[br]or avoid water loss.

9:59:59.000,9:59:59.000
So extreme examples of resistors[br]can be found in succulents,

9:59:59.000,9:59:59.000
they tend to be small, ver attractive,

9:59:59.000,9:59:59.000
but they hold onto their water[br]at such great cost

9:59:59.000,9:59:59.000
that they grow extremely slowly.

9:59:59.000,9:59:59.000
Examples of avoidance of water loss[br]are found in trees and shrubs.

9:59:59.000,9:59:59.000
They send down very deep roots,

9:59:59.000,9:59:59.000
mine subterranean water supplies,

9:59:59.000,9:59:59.000
and just keep flushing[br]it through them at all times,

9:59:59.000,9:59:59.000
keeping themselves hydrated.

9:59:59.000,9:59:59.000
The one on the right is called a Baobab,

9:59:59.000,9:59:59.000
it's also called the upside-down tree,

9:59:59.000,9:59:59.000
simply because the proportion[br]of roots to chutes is so great

9:59:59.000,9:59:59.000
that it looks like the tree[br]is being planted upside down.

9:59:59.000,9:59:59.000
And of course the roots are required[br]for hydration of that plant.

9:59:59.000,9:59:59.000
And probably the most common strategy[br]of avoidance is found in annuals.

9:59:59.000,9:59:59.000
Annuals make up the bulk[br]of our plant food supplies.

9:59:59.000,9:59:59.000
Up the west coast of my country,

9:59:59.000,9:59:59.000
for much the year you don't see[br]much vegetation growth.

9:59:59.000,9:59:59.000
But come the spring rains,

9:59:59.000,9:59:59.000
you get this.

9:59:59.000,9:59:59.000
Flowering of the desert.

9:59:59.000,9:59:59.000
Now the strategy in annuals,

9:59:59.000,9:59:59.000
is to grow only in the rainy season.

9:59:59.000,9:59:59.000
At the end of that season[br]they produce a seed,

9:59:59.000,9:59:59.000
which is dry, eight to 10 percent water,

9:59:59.000,9:59:59.000
but very much alive.

9:59:59.000,9:59:59.000
And anything that is that dry[br]and still alive,

9:59:59.000,9:59:59.000
we call desiccation-tolerant.

9:59:59.000,9:59:59.000
The next time the rainy season comes,

9:59:59.000,9:59:59.000
they germinate and grow,

9:59:59.000,9:59:59.000
and the whole cycle just starts again.

9:59:59.000,9:59:59.000
It's widely believed that the evolution[br]of desiccation-tolerant seeds

9:59:59.000,9:59:59.000
allowed the colonization and the radiation[br]of flowering plants, or angiosperms,

9:59:59.000,9:59:59.000
onto land.

9:59:59.000,9:59:59.000
But back to annuals[br]as our major form of food supplies.

9:59:59.000,9:59:59.000
Wheat, rice and maze form 95 percent[br]of our plant food supplies.

9:59:59.000,9:59:59.000
And it's been a great strategy,

9:59:59.000,9:59:59.000
because in a short space of time[br]you can produce a lot of seed,

9:59:59.000,9:59:59.000
seeds are energy-rich so you can[br]store a lot of food calories,

9:59:59.000,9:59:59.000
you can store it in times of plenty[br]for times of famine,

9:59:59.000,9:59:59.000
but there's a down side.

9:59:59.000,9:59:59.000
The vegetative tissues,

9:59:59.000,9:59:59.000
the roots and leaves of annuals,

9:59:59.000,9:59:59.000
do not have much by way

9:59:59.000,9:59:59.000
of inherent resistance, avoidance[br]or tolerance characteristics.

9:59:59.000,9:59:59.000
They just don't need them.

9:59:59.000,9:59:59.000
They grow in the rainy season

9:59:59.000,9:59:59.000
and they've got a seed to help them[br]survive the rest of the year.

9:59:59.000,9:59:59.000
And so despite concerted[br]efforts in agriculture

9:59:59.000,9:59:59.000
to make crops with improved properties

9:59:59.000,9:59:59.000
of resistance, avoidance and tolerance --

9:59:59.000,9:59:59.000
particularly resistance and avoidance

9:59:59.000,9:59:59.000
because we've had good models[br]to understand how those work --

9:59:59.000,9:59:59.000
we still get images like this.

9:59:59.000,9:59:59.000
Maze crop in Africa,

9:59:59.000,9:59:59.000
two weeks without rain,

9:59:59.000,9:59:59.000
and it's dead.

9:59:59.000,9:59:59.000
Now there is a solution.

9:59:59.000,9:59:59.000
Resurrection plants.

9:59:59.000,9:59:59.000
These plants can lose 95 percent[br]of their cellular water,

9:59:59.000,9:59:59.000
remain in a dry, dead-like state[br]for months to years,

9:59:59.000,9:59:59.000
and give them water,

9:59:59.000,9:59:59.000
they green up and start growing again.

9:59:59.000,9:59:59.000
Like seeds, they are desiccation-tolerant.

9:59:59.000,9:59:59.000
Like seeds, these can withstand extremes[br]of environmental conditions.

9:59:59.000,9:59:59.000
And this is a really rare phenomenon.

9:59:59.000,9:59:59.000
There are only 135 flowering[br]plant species that can do this.

9:59:59.000,9:59:59.000
I'm going to show you a video

9:59:59.000,9:59:59.000
of the resurrection process[br]of these three species

9:59:59.000,9:59:59.000
in that order.

9:59:59.000,9:59:59.000
And at the bottom,

9:59:59.000,9:59:59.000
there's a time axis so you can see[br]how quickly it happens.

9:59:59.000,9:59:59.000
[Video]

9:59:59.000,9:59:59.000
(Applause)

9:59:59.000,9:59:59.000
Pretty amazing, huh?

9:59:59.000,9:59:59.000
So I've spent the last 21 years[br]trying to understand how they do this.

9:59:59.000,9:59:59.000
How do these plants dry without dying?

9:59:59.000,9:59:59.000
And I work on a variety of different[br]Resurrection plants,

9:59:59.000,9:59:59.000
shown here in the hydrated and dry states,

9:59:59.000,9:59:59.000
for a number of reasons.

9:59:59.000,9:59:59.000
One of them being is that[br]each of these plants serve as a model

9:59:59.000,9:59:59.000
for a crop that I'd like[br]to make drought-tolerant.

9:59:59.000,9:59:59.000
So on the extreme top left for example,

9:59:59.000,9:59:59.000
is a grass, it's called[br]Eragrostis Nindensis,

9:59:59.000,9:59:59.000
it's called a close relative called[br]Eragrostis Tef,

9:59:59.000,9:59:59.000
a lot of you might know it as "Tef,"

9:59:59.000,9:59:59.000
it's a staple food in Ethiopia,

9:59:59.000,9:59:59.000
it's gluten-free,

9:59:59.000,9:59:59.000
and it's something we would like[br]to make drought-tolerant.

9:59:59.000,9:59:59.000
The other reason for looking[br]at a number of plants,

9:59:59.000,9:59:59.000
is that, as least initially,

9:59:59.000,9:59:59.000
I wanted to find out:[br]do they do the same thing?

9:59:59.000,9:59:59.000
Do they all use the same mechanisms

9:59:59.000,9:59:59.000
to be able to lose[br]all that water and not die?

9:59:59.000,9:59:59.000
So I undertook what we call[br]a Systems Biology approach.