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 9:59:59.000,9:59:59.000 in order to get[br]a comprehensive understanding 9:59:59.000,9:59:59.000 of desiccation tolerance, 9:59:59.000,9:59:59.000 in which we look at everything 9:59:59.000,9:59:59.000 from the molecular to the whole plant[br]ecophysiological level. 9:59:59.000,9:59:59.000 For example we look at things like 9:59:59.000,9:59:59.000 changes in the plant anatomy[br]when they're dried out, 9:59:59.000,9:59:59.000 and their ultrasctructure. 9:59:59.000,9:59:59.000 We look at the transcriptome, 9:59:59.000,9:59:59.000 which is just a term for a technology 9:59:59.000,9:59:59.000 in which we look at the genes[br]that are switched on or off, 9:59:59.000,9:59:59.000 in response to drying. 9:59:59.000,9:59:59.000 Most genes will code for proteins[br]so we look at the proteome. 9:59:59.000,9:59:59.000 What are the proteins made[br]in response to drying? 9:59:59.000,9:59:59.000 Some proteins would code for enzymes[br]which make metabolytes, 9:59:59.000,9:59:59.000 so we look at the metabolome. 9:59:59.000,9:59:59.000 Now this is important because plants[br]are stuck in the ground. 9:59:59.000,9:59:59.000 They use what I call a highly tuned[br]chemical arsenal 9:59:59.000,9:59:59.000 to protect themselves from all[br]the stresses of their environment. 9:59:59.000,9:59:59.000 So it's important that we look[br] 9:59:59.000,9:59:59.000 at the chemical changes[br]involved in drying. 9:59:59.000,9:59:59.000 The last study that we do[br]at the molecular level 9:59:59.000,9:59:59.000 is we study the lipidome -- 9:59:59.000,9:59:59.000 the lipid changes in response to drying. 9:59:59.000,9:59:59.000 And that's also important 9:59:59.000,9:59:59.000 because all biological membranes[br]are made of lipids. 9:59:59.000,9:59:59.000 They're held as membranes[br]because they're in water. 9:59:59.000,9:59:59.000 Take away the water,[br]those membranes fall apart. 9:59:59.000,9:59:59.000 Lipids also act as signals[br]to turn on genes. 9:59:59.000,9:59:59.000 Then we use physiological[br]and biochemical studies 9:59:59.000,9:59:59.000 to try and understand the function 9:59:59.000,9:59:59.000 of the putative protectants that we've[br]actually discovered in our other studies. 9:59:59.000,9:59:59.000 And we use all of that[br]to try and understand 9:59:59.000,9:59:59.000 how the plant copes[br]with its natural environment. 9:59:59.000,9:59:59.000 Now I've always had the philosphy 9:59:59.000,9:59:59.000 that I needed a comprehensive[br]understanding 9:59:59.000,9:59:59.000 of the mechanisms of desiccation tolerance 9:59:59.000,9:59:59.000 in order to make a meaningful suggestion[br]for a biotic application. 9:59:59.000,9:59:59.000 I'm sure some of you are thinking, 9:59:59.000,9:59:59.000 "by biotic application, so she mean she's[br]going to make genetically modified crops?" 9:59:59.000,9:59:59.000 And the answer to that question is, 9:59:59.000,9:59:59.000 it depends on your definition[br]of genetic modification. 9:59:59.000,9:59:59.000 All of the crops that we eat today,[br]wheat, grass and maze, 9:59:59.000,9:59:59.000 are highly genetically modified[br]from their ancenstors, 9:59:59.000,9:59:59.000 but we don't consider them "GM" 9:59:59.000,9:59:59.000 because they're being produced[br]by conventional breeding. 9:59:59.000,9:59:59.000 If you mean, 9:59:59.000,9:59:59.000 "am I going to put resurrection plant[br]genes into crops?" 9:59:59.000,9:59:59.000 your answer is yes. 9:59:59.000,9:59:59.000 In the essence of time,[br]we have tried that approach. 9:59:59.000,9:59:59.000 More appropriately, 9:59:59.000,9:59:59.000 some of my collaborators at UCT, 9:59:59.000,9:59:59.000 Jennifer Thomson and Suhail Rafudeeen, 9:59:59.000,9:59:59.000 have spearheaded that approach 9:59:59.000,9:59:59.000 and I'm going to show you[br]some data soon. 9:59:59.000,9:59:59.000 But we're about to embark upon[br]an extremely ambitious approach, 9:59:59.000,9:59:59.000 in which we aim to turn on[br]whole suites of genes 9:59:59.000,9:59:59.000 that are already present in every crop. 9:59:59.000,9:59:59.000 They're just never turned on[br]under extreme drought conditions. 9:59:59.000,9:59:59.000 I leave it up to you to decide 9:59:59.000,9:59:59.000 whether those should[br]be called "GM" or not. 9:59:59.000,9:59:59.000 I'm going to now just give you[br]some of the data from that first approach. 9:59:59.000,9:59:59.000 And in order to do that 9:59:59.000,9:59:59.000 I have to explain a little bit[br]about how genes work. 9:59:59.000,9:59:59.000 So you probably all know 9:59:59.000,9:59:59.000 that genes are made[br]of double-stranded DNA. 9:59:59.000,9:59:59.000 It's wound very tightly into chromosomes 9:59:59.000,9:59:59.000 that are present[br]in every cell of your body, 9:59:59.000,9:59:59.000 or in a plant's body. 9:59:59.000,9:59:59.000 If you unwind that DNA, you get genes. 9:59:59.000,9:59:59.000 And each gene has a promoter, 9:59:59.000,9:59:59.000 which is an on/off switch, 9:59:59.000,9:59:59.000 the gene coding region, 9:59:59.000,9:59:59.000 and then the terminator, 9:59:59.000,9:59:59.000 which indicates 9:59:59.000,9:59:59.000 that this is the end of this gene,[br]the next gene will start. 9:59:59.000,9:59:59.000 Now promoters are not[br]simple on-off switches. 9:59:59.000,9:59:59.000 They normally require[br]a lot of fine tuning, 9:59:59.000,9:59:59.000 lots of things to be present and correct[br]before that gene is switched on. 9:59:59.000,9:59:59.000 So what's typically done[br]in biotech studies 9:59:59.000,9:59:59.000 is that we use an inducible promoter, 9:59:59.000,9:59:59.000 we know how to switch it on. 9:59:59.000,9:59:59.000 We couple that to genes of interest, 9:59:59.000,9:59:59.000 and put that into a plant 9:59:59.000,9:59:59.000 and see how the plant responds. 9:59:59.000,9:59:59.000 Now in the study that I'm going[br]to talk to you about, 9:59:59.000,9:59:59.000 my collaborators used[br]a drought-induced promoter, 9:59:59.000,9:59:59.000 which we discovered[br]in a resurrection plant. 9:59:59.000,9:59:59.000 Now the nice thing about this promoter[br]is that we do nothing. 9:59:59.000,9:59:59.000 The plant itself senses drought. 9:59:59.000,9:59:59.000 And we've used it 9:59:59.000,9:59:59.000 to drive antioxidant genes[br]from resurrection plants. 9:59:59.000,9:59:59.000 Why antioxidant genes? 9:59:59.000,9:59:59.000 Well, all stresses,[br]particularly drought stress, 9:59:59.000,9:59:59.000 results in the formation of free radicals, 9:59:59.000,9:59:59.000 or reactive oxygen species, 9:59:59.000,9:59:59.000 which are highly damaging[br]and can cause crop death. 9:59:59.000,9:59:59.000 What antioxidants do is stop that damage. 9:59:59.000,9:59:59.000 So here's some data from a main strain[br]that's very popularly used in Africa. 9:59:59.000,9:59:59.000 To the left of the arrow are plants[br]without the genes, 9:59:59.000,9:59:59.000 to the right -- 9:59:59.000,9:59:59.000 plants with the antioxidant genes. 9:59:59.000,9:59:59.000 After three weeks without watering, 9:59:59.000,9:59:59.000 the ones with the genes[br]do a hell of a lot better. 9:59:59.000,9:59:59.000 Now to the final approach. 9:59:59.000,9:59:59.000 My research has shown 9:59:59.000,9:59:59.000 that there's considerable similarity[br]in the mechanisms of desiccation tolerance 9:59:59.000,9:59:59.000 in seeds and resurrection plants. 9:59:59.000,9:59:59.000 So I ask the question, 9:59:59.000,9:59:59.000 are they using the same genes? 9:59:59.000,9:59:59.000 Or slightly differently phrased, 9:59:59.000,9:59:59.000 are resurrection plants utilizing genes[br]evolved for seed desiccation tolerance 9:59:59.000,9:59:59.000 in their roots and leaves? 9:59:59.000,9:59:59.000 Have they re-tasked these seed genes 9:59:59.000,9:59:59.000 in roots and leaves[br]of resurrection plants? 9:59:59.000,9:59:59.000 And I answer that question, 9:59:59.000,9:59:59.000 as a consequence of a lot[br]of research from my group 9:59:59.000,9:59:59.000 and recent collaborations from a group[br]of Henk Hilhorst in the Netherlands, 9:59:59.000,9:59:59.000 Mel Oliver in the United States, 9:59:59.000,9:59:59.000 and Julia Buitink, in France, 9:59:59.000,9:59:59.000 the answer is, yes. 9:59:59.000,9:59:59.000 There is a core set of genes[br]that are involved in both. 9:59:59.000,9:59:59.000 And I'm going to illustrate this[br]very crudely for maze, 9:59:59.000,9:59:59.000 where the chromosomes[br]below the off switch 9:59:59.000,9:59:59.000 represent all the genes that are required[br]for desiccation tolerance. 9:59:59.000,9:59:59.000 So as maze seeds dried on[br]at the end of their period of development, 9:59:59.000,9:59:59.000 they switch these genes on. 9:59:59.000,9:59:59.000 Resurrection plants[br]switch on the same genes 9:59:59.000,9:59:59.000 when they're dried on. 9:59:59.000,9:59:59.000 All modern crops, therefore, 9:59:59.000,9:59:59.000 have these genes[br]in their roots and leaves, 9:59:59.000,9:59:59.000 they just never switch them on. 9:59:59.000,9:59:59.000 They only switch them on in seed tissues. 9:59:59.000,9:59:59.000 So what we're trying to do right now 9:59:59.000,9:59:59.000 is to understand the environmental[br]and cellular signals 9:59:59.000,9:59:59.000 which switch on these genes[br]in resurrection plants, 9:59:59.000,9:59:59.000 to mimic the process in crops. 9:59:59.000,9:59:59.000 And just a final thought. 9:59:59.000,9:59:59.000 What we're trying to do very rapidly, 9:59:59.000,9:59:59.000 is to repeat what nature did[br]in the evolution of resurrection plants 9:59:59.000,9:59:59.000 some 10 to 40 million years ago. 9:59:59.000,9:59:59.000 My plants and I[br]thank you for your attention. 9:59:59.000,9:59:59.000 (Applause)