WEBVTT

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I believe that the secret to producing
extremely drought tolerant crops,

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which should go some way
to providing food security in the world,

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lies in Resurrection plants,

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pictured here, in an extremely
droughted state.

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Now you might think
that these plants look dead,

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but they're not.

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Give them water,

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and they will resurrect, green up,
start growing,

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in 12 to 48 hours.

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No why would I suggest

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that producing drought tolerant crops
will go towards providing food security?

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Well the current world population
is around 7 billion.

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And it's estimated that by 2050,

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we'll be between 9 and 10 billion people,

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with the bulk of this growth
happening in Africa.

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The food and agricultural
organizations of the world

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have suggested that we need a 70 percent
increase in current agricultural practice

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to meet that demand.

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Now given that plants
are at the base of the food chain,

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most of that's going
to have to come from plants.

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Now that percentage of 70 percent

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does not take into consideration
the potential effects of climate change.

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This is taken from a study by Dye
published in 2011,

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where he took into consideration


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all the potential effects
of climate change

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and expressed them
amongst other things,

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increased aridity due to lack or rain
or infrequent rain.

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Now the areas in red shown here,

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are areas that until recently, have been
very successfully used for agriculture,

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but cannot anymore
because of lack of rain fall.

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This is the situation
that's predicted to happen in 2050.

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Much of Africa,

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in fact much of the world,

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is going to be in trouble.

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We're going to have to think of some
very smart ways of producing food.

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And preferably among them,
some drought-tolerant crops.

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The other thing to remember about Africa

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is that most of the
agriculture is rain fed.

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Now making drought-tolerant crops
is not the easiest thing in the world.

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And the reason for this is water.

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Water is essential to life on this planet.

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All living, actively
metabolizing organisms,

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from microbes to you and I,

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are comprised predominately of water,


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all life reactions happen in water,

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and loss of a small amount
of water results in death.

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You and I are 65 percent water,

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we lose one percent of that, we die.

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But we can make behavioral
changes to avoid that.

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Plants can't.

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They're stuck in the ground.

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So in the first instance, they have
a little bit more water than us,

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about 95 percent water,

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and they can lose
a little bit more than us,

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like 10 to about 70 percent,
depending on the species,

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but for short periods only.

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Most of them will either try to resist
or avoid water loss.

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So extreme examples of resistors
can be found in succulents,

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they tend to be small, ver attractive,

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but they hold onto their water
at such great cost

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that they grow extremely slowly.

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Examples of avoidance of water loss
are found in trees and shrubs.

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They send down very deep roots,

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mine subterranean water supplies,

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and just keep flushing
it through them at all times,

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keeping themselves hydrated.

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The one on the right is called a Baobab,

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it's also called the upside-down tree,

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simply because the proportion
of roots to chutes is so great

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that it looks like the tree
is being planted upside down.

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And of course the roots are required
for hydration of that plant.

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And probably the most common strategy
of avoidance is found in annuals.

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Annuals make up the bulk
of our plant food supplies.

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Up the west coast of my country,

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for much the year you don't see
much vegetation growth.

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But come the spring rains,

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you get this.

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Flowering of the desert.

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Now the strategy in annuals,

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is to grow only in the rainy season.

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At the end of that season
they produce a seed,

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which is dry, eight to 10 percent water,

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but very much alive.

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And anything that is that dry
and still alive,

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we call desiccation-tolerant.

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The next time the rainy season comes,

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they germinate and grow,

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and the whole cycle just starts again.

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It's widely believed that the evolution
of desiccation-tolerant seeds

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allowed the colonization and the radiation
of flowering plants, or angiosperms,

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onto land.

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But back to annuals
as our major form of food supplies.

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Wheat, rice and maze form 95 percent
of our plant food supplies.

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And it's been a great strategy,

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because in a short space of time
you can produce a lot of seed,

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seeds are energy-rich so you can
store a lot of food calories,

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you can store it in times of plenty
for times of famine,

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but there's a down side.

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The vegetative tissues,

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the roots and leaves of annuals,

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do not have much by way

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of inherent resistance, avoidance
or tolerance characteristics.

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They just don't need them.

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They grow in the rainy season

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and they've got a seed to help them
survive the rest of the year.

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And so despite concerted
efforts in agriculture

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to make crops with improved properties

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of resistance, avoidance and tolerance --

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particularly resistance and avoidance

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because we've had good models
to understand how those work --

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we still get images like this.

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Maze crop in Africa,

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two weeks without rain,

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and it's dead.

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Now there is a solution.

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Resurrection plants.

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These plants can lose 95 percent
of their cellular water,

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remain in a dry, dead-like state
for months to years,

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and give them water,

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they green up and start growing again.

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Like seeds, they are desiccation-tolerant.

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Like seeds, these can withstand extremes
of environmental conditions.

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And this is a really rare phenomenon.

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There are only 135 flowering
plant species that can do this.

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I'm going to show you a video

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of the resurrection process
of these three species

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in that order.

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And at the bottom,

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there's a time axis so you can see
how quickly it happens.

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[Video]

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(Applause)

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Pretty amazing, huh?

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So I've spent the last 21 years
trying to understand how they do this.

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How do these plants dry without dying?

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And I work on a variety of different
Resurrection plants,

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shown here in the hydrated and dry states,

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for a number of reasons.

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One of them being is that
each of these plants serve as a model

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for a crop that I'd like
to make drought-tolerant.

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So on the extreme top left for example,

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is a grass, it's called
Eragrostis Nindensis,

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it's called a close relative called
Eragrostis Tef,

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a lot of you might know it as "Tef,"

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it's a staple food in Ethiopia,

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it's gluten-free,

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and it's something we would like
to make drought-tolerant.

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The other reason for looking
at a number of plants,

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is that, as least initially,

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I wanted to find out:
do they do the same thing?

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Do they all use the same mechanisms

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to be able to lose
all that water and not die?

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So I undertook what we call
a Systems Biology approach.