0:00:05 > 0:00:09Of all life on Earth, there's something more mysterious
0:00:09 > 0:00:12yet more vital to our survival than anything else.
0:00:15 > 0:00:17Its birth is violent.
0:00:19 > 0:00:21Much of its life is hidden underground.
0:00:25 > 0:00:28And only at the end of its life cycle does it reveal its identity.
0:00:31 > 0:00:32The mushroom.
0:00:39 > 0:00:41I'm Professor Richard Fortey.
0:00:41 > 0:00:44'I've been fascinated by mushrooms all my life.'
0:00:44 > 0:00:46Nice find.
0:00:46 > 0:00:50'I love to collect and study them.'
0:00:50 > 0:00:54Many people think of mushrooms just as something to eat,
0:00:54 > 0:00:58or maybe as decoration in folk tales.
0:00:58 > 0:01:00But nothing could be further from the truth.
0:01:02 > 0:01:05They have a secret life so magical,
0:01:05 > 0:01:07so weird,
0:01:07 > 0:01:09that it defies imagination,
0:01:09 > 0:01:12and I'm going to reveal it as never before.
0:01:16 > 0:01:22I've set up my own lab to unlock the mysteries of mushrooms.
0:01:22 > 0:01:23Oh, look at that!
0:01:23 > 0:01:25They're like geysers.
0:01:26 > 0:01:29I'll discover their astonishing powers.
0:01:30 > 0:01:33What makes them the fastest...
0:01:33 > 0:01:34the largest...
0:01:36 > 0:01:39..and some of the deadliest living things on the planet.
0:01:41 > 0:01:45Half a cap will kill you and kill you slowly and painfully.
0:01:46 > 0:01:50And I'll meet the people turning those powers to our advantage
0:01:50 > 0:01:53to create new medicines
0:01:53 > 0:01:54and new materials.
0:01:54 > 0:01:57The innovation we have here is the future of energy production
0:01:57 > 0:02:00and even devices and products like your iPhone.
0:02:02 > 0:02:05To discover what gives mushrooms their extraordinary abilities,
0:02:05 > 0:02:09I'm going to follow their story from birth, through life, to death.
0:02:10 > 0:02:14A story so strange it seems almost alien,
0:02:14 > 0:02:19yet it will reveal why mushrooms are crucial to all life on Earth,
0:02:19 > 0:02:23and why they have a powerful connection to you and me.
0:02:37 > 0:02:40The only place many of us encounter mushrooms is here.
0:02:43 > 0:02:45Cultivated edible varieties like these,
0:02:45 > 0:02:49are all most of us think about when it comes to mushrooms.
0:02:49 > 0:02:51We Brits can't get enough.
0:02:51 > 0:02:54It's a multimillion pound business in the UK.
0:02:56 > 0:02:59But there's so much more to mushrooms
0:02:59 > 0:03:03than this fine example in the fresh food counter.
0:03:03 > 0:03:07This mushroom is just one species from an enormous kingdom,
0:03:07 > 0:03:09the kingdom of the fungi...
0:03:10 > 0:03:13..and fungi are hidden away in all kinds of food products
0:03:13 > 0:03:16in this supermarket in ways you wouldn't expect.
0:03:20 > 0:03:23Look hard enough and every aisle reveals evidence
0:03:23 > 0:03:26of how fungi underpin modern living.
0:03:27 > 0:03:29Cheese.
0:03:30 > 0:03:33My favourite Stilton cheese, well, it's blue,
0:03:33 > 0:03:35and the blue is a fungus.
0:03:37 > 0:03:39A lot of fizzy drinks have citric acid in them,
0:03:39 > 0:03:42and that's produced by a fungus called Aspergillus niger
0:03:42 > 0:03:44in huge quantities.
0:03:44 > 0:03:49Many detergents also contain citric acid, just like fizzy drinks.
0:03:49 > 0:03:53Ah, here's soy sauce, bread,
0:03:53 > 0:03:56Quorn, chocolate, fruit juices.
0:03:56 > 0:03:58Well, sometimes they have a bitter taste,
0:03:58 > 0:04:00which can be removed by another fungus.
0:04:02 > 0:04:03Salmon, red salmon.
0:04:03 > 0:04:05The red colour, I'm afraid,
0:04:05 > 0:04:08is sometimes due to a fungus called Phaffia.
0:04:09 > 0:04:11Some of the protein in pet foods,
0:04:11 > 0:04:16which keeps your animals healthy is actually produced by fungi.
0:04:18 > 0:04:19And, of course, booze.
0:04:19 > 0:04:22The fermenting activity of Saccharomyces,
0:04:22 > 0:04:25turning sugars into alcohol.
0:04:33 > 0:04:36Clearly, our supermarket shop just wouldn't be the same without fungi.
0:04:36 > 0:04:40They're hidden away in all sorts of ways in the products.
0:04:40 > 0:04:44They must have a series of special biochemical tricks up their sleeve.
0:04:46 > 0:04:50But how exactly is it that they seem to turn up everywhere
0:04:50 > 0:04:52and affect so many parts of our lives?
0:04:55 > 0:04:58To begin to answer that question, I'm going to a place
0:04:58 > 0:05:01where I encounter fungi in all their forms.
0:05:03 > 0:05:07Head out into any woodland like this one in the Scottish Borders,
0:05:07 > 0:05:08and if you look hard enough,
0:05:08 > 0:05:11you'll start finding them everywhere.
0:05:22 > 0:05:25To me, they're fascinating.
0:05:25 > 0:05:29Some may think they look like any other plant,
0:05:29 > 0:05:32but in fact, they're a different organism altogether.
0:05:34 > 0:05:37Fungi evolved as a kingdom in their own right,
0:05:37 > 0:05:40distinct from plants and animals,
0:05:40 > 0:05:43over one and a half billion years ago.
0:05:43 > 0:05:44It's thought that in variety,
0:05:44 > 0:05:47they outnumber plants by at least ten to one.
0:05:49 > 0:05:52And searching for them is my favourite pastime.
0:05:55 > 0:05:59Some people might think of autumn as a rather gloomy time of year,
0:05:59 > 0:06:02but for me, it's pure joy.
0:06:02 > 0:06:04I can take my basket, I can go into the woods...
0:06:05 > 0:06:08..and I can do my mushroom foraying.
0:06:08 > 0:06:10I've been doing it for decades.
0:06:11 > 0:06:12What's the thrill of it?
0:06:12 > 0:06:16Well, to the left of the path, to the right of the path,
0:06:16 > 0:06:19dozens of different kinds of fungi are erupting.
0:06:20 > 0:06:25But, I suppose, the most primeval feeling, the basic one,
0:06:25 > 0:06:29is still the thrill of discovery, the thrill of the chase.
0:06:34 > 0:06:39You may not realise that what we call the mushroom is, in fact,
0:06:39 > 0:06:40just one type of fungus.
0:06:40 > 0:06:43It's the form that we are most familiar with
0:06:43 > 0:06:46and it's certainly the easiest to recognise.
0:06:49 > 0:06:51The head of a mushroom is its cap.
0:06:56 > 0:06:57And many have a stalk.
0:07:01 > 0:07:03Look underneath the cap,
0:07:03 > 0:07:07and you'll often find a set of sharp ridges known as gills.
0:07:07 > 0:07:09Ah-ha!
0:07:09 > 0:07:13Well, now, this is, of course, the archetypal mushroom.
0:07:13 > 0:07:17It's the one that the gnomes sit on top of.
0:07:17 > 0:07:19It's the fly agaric.
0:07:19 > 0:07:23I can see other species really, really close to hand.
0:07:23 > 0:07:27This is the king of the edible mushrooms, the cep,
0:07:27 > 0:07:29the penny bun,
0:07:29 > 0:07:30porcini.
0:07:30 > 0:07:33The fact that it's got so many names is a measure
0:07:33 > 0:07:37of just how highly regarded it is as an edible fungus.
0:07:37 > 0:07:38It's one of the best.
0:07:41 > 0:07:43'But as well as the quintessential mushroom...'
0:07:43 > 0:07:44Bit hazardous.
0:07:44 > 0:07:48'..if you look a little harder, you'll find a host of other fungi
0:07:48 > 0:07:50'that don't look like mushrooms at all.'
0:07:51 > 0:07:54Ah, well, now, here's something completely different.
0:07:54 > 0:07:57Perhaps doesn't look like a fungus at first sight to people.
0:07:57 > 0:07:59It's one of the coral fungi.
0:08:00 > 0:08:02This is an ear fungus.
0:08:02 > 0:08:07They're still fungi but they're very, very different sort of fungi.
0:08:07 > 0:08:08Yellow brain fungus.
0:08:08 > 0:08:11Doesn't look like anything from this Earth, really, does it?
0:08:12 > 0:08:14It's the beefsteak fungus.
0:08:15 > 0:08:19And you can see why - it looks a bit like raw liver.
0:08:21 > 0:08:25'In fact, this organism can take so many weird and wonderful forms,
0:08:25 > 0:08:27'knowing what it is you're looking at
0:08:27 > 0:08:32'can sometimes be a challenge, even for an experienced forayer like me.'
0:08:32 > 0:08:36Wow, now, that is something really weird.
0:08:36 > 0:08:38I'm not quite sure what's going on.
0:08:38 > 0:08:41It's absolutely extraordinary. That's one coming back to the lab.
0:08:43 > 0:08:48Almost every foray I go on, I find something new and intriguing.
0:08:48 > 0:08:52Time to take a closer look at exactly what's in my basket.
0:08:54 > 0:08:58This is our specially-built mushroom lab
0:08:58 > 0:09:00where I'll be unlocking the mysteries of fungi
0:09:00 > 0:09:03with the help of mycologist Dr Patrick Hickey.
0:09:03 > 0:09:05Well, this is quite a set-up you've got here.
0:09:07 > 0:09:09Their first secret is their identity.
0:09:10 > 0:09:13So here we are with our haul back from the woods,
0:09:13 > 0:09:16and what a variety we've got in the basket.
0:09:16 > 0:09:19Of course, we notice things like the colour, of course.
0:09:19 > 0:09:20The smell.
0:09:20 > 0:09:24Oh, yeah, that's got a really sweet smell to it, very sweet odour.
0:09:24 > 0:09:27So fungus identification uses all your senses.
0:09:27 > 0:09:29It's a very sensory experience.
0:09:29 > 0:09:32But there's another way we can really narrow down
0:09:32 > 0:09:35the mystery of a mushroom and positively identify it
0:09:35 > 0:09:37and that's by doing something called a spore print.
0:09:37 > 0:09:40Every mushroom has its own unique spore print
0:09:40 > 0:09:43and to do a spore print, we cut the stem off,
0:09:43 > 0:09:46and then place the cap onto a piece of paper
0:09:46 > 0:09:47and just leave it for a few hours.
0:09:47 > 0:09:50When you come back and lift it up,
0:09:50 > 0:09:53you'll see the mushroom has deposited a layer of spores
0:09:53 > 0:09:55and they look just like fingerprints.
0:09:55 > 0:09:57It's a bit like taking a fingerprint from a mushroom.
0:09:59 > 0:10:02These spores are like the seeds of a mushroom
0:10:02 > 0:10:06and the patterns they create can reveal some surprises,
0:10:06 > 0:10:09even when two mushrooms appear to look the same.
0:10:09 > 0:10:12So here we've got two similar looking...
0:10:12 > 0:10:14- Almost the same, yeah. - ..white mushrooms,
0:10:14 > 0:10:18but reveal the spores - one's startlingly white
0:10:18 > 0:10:20and the other's very black.
0:10:20 > 0:10:23Yeah, it's a key in the identification of the mushroom.
0:10:29 > 0:10:32So we have such a variety of colours.
0:10:32 > 0:10:34We've got a sort of purple here.
0:10:34 > 0:10:36We've got cream, we've got white,
0:10:36 > 0:10:41- very pure white, rust brown, even pinkish.- Yeah.
0:10:41 > 0:10:44And I have to say what a beautiful pattern it makes too.
0:10:44 > 0:10:47I mean, aesthetically, extremely pleasing.
0:10:47 > 0:10:50They're wonderful. They're just like the silhouettes of a mushroom,
0:10:50 > 0:10:53and that colour of the spore print is unique to that type of mushroom
0:10:53 > 0:10:56and they don't change throughout the mushroom's life cycle.
0:11:00 > 0:11:02The spore prints reveal
0:11:02 > 0:11:06that mushrooms are more varied and complex than they might appear.
0:11:06 > 0:11:10Their world is mysterious and little known,
0:11:10 > 0:11:14yet they have the power to affect our lives in unexpected ways.
0:11:14 > 0:11:17One of the most striking displays of that power
0:11:17 > 0:11:20takes us to the most unlikely place.
0:11:28 > 0:11:32This is Mark Gilchrist, a consultant pharmacist
0:11:32 > 0:11:34at St Mary's Hospital, London.
0:11:34 > 0:11:38He spends much of his day administering and prescribing
0:11:38 > 0:11:41the most widely-used type of drug on the planet -
0:11:41 > 0:11:43antibiotics.
0:11:46 > 0:11:49Antibiotics are tremendously important
0:11:49 > 0:11:51in our fight against infection.
0:11:51 > 0:11:54Up to about 30% of patients within a hospital setting
0:11:54 > 0:11:56can be on antibiotics at any one time
0:11:56 > 0:11:59and that's used to treat things like pneumonias
0:11:59 > 0:12:01to simple skin and soft tissue infections
0:12:01 > 0:12:04and prevent surgical site infections post operatively.
0:12:06 > 0:12:10The invention of antibiotics has been a game changer
0:12:10 > 0:12:13for medicine and mankind.
0:12:13 > 0:12:15And we owe it all to fungi.
0:12:20 > 0:12:24In 1928, scientist Alexander Fleming
0:12:24 > 0:12:26was carrying out research at St Mary's.
0:12:27 > 0:12:30He was studying the staphylococcus bacterium,
0:12:30 > 0:12:35and left some samples on his desk, before heading off on holiday,
0:12:35 > 0:12:38expecting them to grow and develop while he was away.
0:12:40 > 0:12:43When Fleming returned from his holiday to resume his research
0:12:43 > 0:12:46on bacteria here in this lab,
0:12:46 > 0:12:48he noticed something extraordinary.
0:12:50 > 0:12:53His bacteria samples were dead.
0:12:53 > 0:12:55They had been completely destroyed by fungi.
0:12:57 > 0:13:00Intrigued by why this had happened,
0:13:00 > 0:13:02Fleming examined his samples further.
0:13:03 > 0:13:08He realised that a fungus spore, possibly from a lab below,
0:13:08 > 0:13:11must have landed on the gel plate and germinated.
0:13:14 > 0:13:18The spore had rapidly started to feed on the contents of the dish,
0:13:18 > 0:13:20starving and ultimately killing the bacteria.
0:13:22 > 0:13:25The significance wasn't lost on Fleming.
0:13:25 > 0:13:28This could be a new way to fight bacterial infection
0:13:28 > 0:13:29inside the human body.
0:13:31 > 0:13:35His discovery led to the creation of the world's first antibiotic -
0:13:35 > 0:13:37penicillin.
0:13:38 > 0:13:42And it only happened thanks to some tiny spores from a fungus,
0:13:42 > 0:13:44carried on the breeze.
0:13:45 > 0:13:49But to understand how those spores came to be there at all,
0:13:49 > 0:13:53we need to delve deeper into the secret world of fungi,
0:13:53 > 0:13:57right back to the start of their life cycle,
0:13:57 > 0:13:59to the moment a new fungus begins.
0:14:12 > 0:14:13I've come to Scotland
0:14:13 > 0:14:17to see something I've always wanted to see but never have,
0:14:17 > 0:14:20although I've rehearsed it many times in my mind's eye.
0:14:23 > 0:14:27This is one of the largest mushroom farms in the UK,
0:14:27 > 0:14:29and inside each of these polytunnels,
0:14:29 > 0:14:33there's a spectacular natural phenomenon taking place -
0:14:33 > 0:14:34the birth of fungi.
0:14:47 > 0:14:51It's a magical process, normally invisible,
0:14:51 > 0:14:55but tonight I'm going to see it clearly for the first time.
0:14:59 > 0:15:01Well, to a mushroom person, of course,
0:15:01 > 0:15:03this is like being in heaven,
0:15:03 > 0:15:09and everywhere you look, it's extraordinary -
0:15:09 > 0:15:13this laser torch picks out little white specks.
0:15:13 > 0:15:16They're so numerous. This is like shining a beam
0:15:16 > 0:15:17up into the Milky Way.
0:15:17 > 0:15:22Billions upon billions of spores in the air all around us,
0:15:22 > 0:15:25and they're ubiquitous, so they're going up to the ceiling
0:15:25 > 0:15:27they're going out the door,
0:15:27 > 0:15:29they're doubtless going into my lungs.
0:15:32 > 0:15:38If you want a graphic demonstration of how prolific mushrooms are,
0:15:38 > 0:15:40here it is.
0:15:46 > 0:15:50So this is how most fungi begin life.
0:15:51 > 0:15:55The mushroom spews out many millions of spores every hour,
0:15:55 > 0:15:58for as long as it remains above the ground...
0:15:59 > 0:16:03..each of them carrying the potential to be a new fungus.
0:16:04 > 0:16:06It's mesmerising to watch,
0:16:06 > 0:16:09but I want to know exactly what's going on here
0:16:09 > 0:16:13and to do that, I'll need more than a laser light.
0:16:15 > 0:16:17Back in the mushroom lab,
0:16:17 > 0:16:21Patrick can reveal the hidden mechanisms of mushroom birth.
0:16:21 > 0:16:23A mushroom, also known as a fruiting body,
0:16:23 > 0:16:26really is just the reproductive structure of a fungus
0:16:26 > 0:16:29and its sole purpose is to produce spores.
0:16:29 > 0:16:31So to look at these in more detail,
0:16:31 > 0:16:34what I'm going to do is take a very thin section
0:16:34 > 0:16:36through this mushroom cap
0:16:36 > 0:16:40and put it onto a microscope slide.
0:16:45 > 0:16:48There we go... Ah!
0:16:48 > 0:16:50That's the business, isn't it?
0:16:50 > 0:16:54Yeah, so the large cylindrical kind of clear part of the cell
0:16:54 > 0:16:59is the basidium and those little spiky bits protruding from it
0:16:59 > 0:17:02are called the sterigmata and they hold the spores in place.
0:17:02 > 0:17:05Now, eventually, when those spores are fully ripened,
0:17:05 > 0:17:07they'll drop off into that air space between the gills,
0:17:07 > 0:17:09and fall down from the mushroom.
0:17:09 > 0:17:12That whole structure, including the spores,
0:17:12 > 0:17:14is about the width of a human hair, and, remember, these gills
0:17:14 > 0:17:17are packed with them. They're completely lined with a layer
0:17:17 > 0:17:20of these basidia continually producing spores.
0:17:20 > 0:17:22It's a production line.
0:17:22 > 0:17:25It's an extraordinary thought, isn't it? This tiny object,
0:17:25 > 0:17:27just a few thousandths of a millimetre long,
0:17:27 > 0:17:30contains the potentiality for a new mushroom colony.
0:17:30 > 0:17:32Exactly.
0:17:33 > 0:17:38This constant production line, forming and releasing spores,
0:17:38 > 0:17:42is exactly what I saw so vividly in action at the mushroom farm.
0:17:42 > 0:17:45But that's just one way mushrooms can spread their spores.
0:17:45 > 0:17:48Others do it in a completely different way.
0:17:50 > 0:17:53This is an orange peel fungus,
0:17:53 > 0:17:54and it's part of a large group
0:17:54 > 0:17:58that fire their spores vertically, with explosive results,
0:17:58 > 0:18:02as we can see here when the action is slowed down 600 times.
0:18:11 > 0:18:13Oh, look at that!
0:18:13 > 0:18:15They're like geysers erupting.
0:18:19 > 0:18:23The spores are incredibly prolific. Throughout the course of a day,
0:18:23 > 0:18:25each fungus might be capable of producing over a million spores
0:18:25 > 0:18:28and over the lifetime of that fungus,
0:18:28 > 0:18:30we're into tens to hundreds of millions.
0:18:37 > 0:18:41Well, that's extraordinary footage. I've never, ever seen anything
0:18:41 > 0:18:45so graphically displaying the way fungi get rid of their spores.
0:18:45 > 0:18:47It's a truly impressive fungus.
0:18:53 > 0:18:57These fungi can reload and fire time and time again,
0:18:57 > 0:18:59often for many days on end.
0:19:02 > 0:19:03And how that works
0:19:03 > 0:19:06was a brilliant discovery made by someone you wouldn't expect.
0:19:14 > 0:19:18Beatrix Potter is famous for penning The Tale Of Peter Rabbit,
0:19:18 > 0:19:20but what's less well known,
0:19:20 > 0:19:23is that she was one of the leading mushroom biologists of her time.
0:19:25 > 0:19:28Both Potter and pioneering biologist Arthur Buller
0:19:28 > 0:19:31spent much of their lives trying to find out
0:19:31 > 0:19:33how some mushrooms release their spores.
0:19:38 > 0:19:41They discovered that a tiny drop of fluid,
0:19:41 > 0:19:45now known as Buller's drop, forms at the base of every spore.
0:19:49 > 0:19:52As the spore ripens and begins to detach,
0:19:52 > 0:19:56the Buller's drop fuses with a second tiny water droplet
0:19:56 > 0:19:58that forms at the side of the spore.
0:19:58 > 0:20:02Like two raindrops joining together on a windowpane,
0:20:02 > 0:20:06this fusion causes a rapid shift in mass
0:20:06 > 0:20:09that dislodges the spore in such a spectacular fashion.
0:20:14 > 0:20:17This microscopic process all takes place
0:20:17 > 0:20:19in a few millionths of a second
0:20:19 > 0:20:21and is key to how many fungi reproduce.
0:20:23 > 0:20:26But of them all, there's one particular species
0:20:26 > 0:20:27that's a record breaker.
0:20:30 > 0:20:33You may think that the fastest organism on the planet
0:20:33 > 0:20:36is a cheetah or maybe a peregrine falcon,
0:20:36 > 0:20:38but you'd be wrong.
0:20:38 > 0:20:41Allowing for scale, the speediest organism on the planet
0:20:41 > 0:20:43is actually a tiny fungus.
0:20:43 > 0:20:46It grows on top of cowpats.
0:20:47 > 0:20:53It's called Pilobolus crystallinus, or the "Hat Thrower" fungus,
0:20:53 > 0:20:56and no other species demonstrates better
0:20:56 > 0:20:58the importance of the spore release mechanism.
0:21:02 > 0:21:06This little fungus feeds on the dung of herbivores,
0:21:06 > 0:21:10but when the supply of nutrients from one pile has been exhausted,
0:21:10 > 0:21:12it needs to move on,
0:21:12 > 0:21:15and to do that, it has to get out of the dung
0:21:15 > 0:21:17and onto new blades of grass.
0:21:17 > 0:21:19That's the equivalent of you or I
0:21:19 > 0:21:23trying to throw a tennis ball over the Eiffel Tower.
0:21:23 > 0:21:25But, then, you or I can't do this.
0:21:25 > 0:21:27BANG
0:21:27 > 0:21:30MUSIC: "Zorba's Dance" by Mikis Theodorakis
0:21:34 > 0:21:37Using water drop acceleration, these spore capsules,
0:21:37 > 0:21:40seen as little black hats, can be fired at a speed
0:21:40 > 0:21:45of up to 40mph in just two millionths of a second,
0:21:45 > 0:21:48pulling an astonishing 20,000 Gs in the process.
0:21:49 > 0:21:51BANG
0:21:51 > 0:21:54The little "Hat Thrower" fungus is a wonderful example
0:21:54 > 0:21:57of the sophistication of fungus evolution.
0:21:57 > 0:22:01It throws its spore body more than a thousand times its own length
0:22:01 > 0:22:04into clear grass, away from cowpats,
0:22:04 > 0:22:07so that the cows will come along, graze the grass,
0:22:07 > 0:22:11incorporate the spores and so propagate another generation.
0:22:14 > 0:22:17The "Hat Thrower" shows just how ingenious fungi are
0:22:17 > 0:22:19when it comes to reproduction.
0:22:20 > 0:22:24They will go to extraordinary lengths to ensure their own future.
0:22:25 > 0:22:29It's the key to why fungi have become such a dominant life form
0:22:29 > 0:22:33with such vast numbers of species all over the planet.
0:22:37 > 0:22:42And it's certainly a talent to which humankind owes a great deal.
0:22:46 > 0:22:51But as impressive as spore dispersal might be,
0:22:51 > 0:22:54it's just the beginning of the fungus's life story.
0:22:55 > 0:22:59It's the next stage that truly reveals why they are
0:22:59 > 0:23:01so vital to all life on Earth.
0:23:03 > 0:23:07So far we've just been looking at the fruit body of the mushroom.
0:23:07 > 0:23:11Indeed, I suppose to most people they think that IS the mushroom.
0:23:12 > 0:23:14But it's only part of the story.
0:23:15 > 0:23:18To discover how mushrooms relate
0:23:18 > 0:23:21to so many other organisms on our planet,
0:23:21 > 0:23:25we have to go further, we have to go underground.
0:23:35 > 0:23:37You'd be forgiven for thinking that what we see
0:23:37 > 0:23:41above the ground is the main part of the fungus...
0:23:42 > 0:23:47..but, in fact, the vast majority of the organism is hidden underground.
0:23:47 > 0:23:51It's a huge web of tiny threads, spreading out in search of food.
0:23:53 > 0:23:56And the only way many fungi can get what they need,
0:23:56 > 0:23:59is by attaching themselves to other organisms,
0:23:59 > 0:24:02and engaging in a two-way exchange of nutrients.
0:24:06 > 0:24:09It's a process that results in one of the most complex,
0:24:09 > 0:24:12yet crucial relationships in the natural world.
0:24:16 > 0:24:18To discover how this works,
0:24:18 > 0:24:22I'm meeting Kew Gardens mycologist Bryn Dentinger.
0:24:24 > 0:24:28Anywhere from 70% to 90% of all plants on Earth
0:24:28 > 0:24:32will form a very special intimate relationship with fungi
0:24:32 > 0:24:36and the fungi will attach themselves to the plant roots,
0:24:36 > 0:24:39either directly penetrating the roots
0:24:39 > 0:24:42or sometimes they will form sheaths on the outside
0:24:42 > 0:24:45that will envelop the root like a kind of glove.
0:24:46 > 0:24:48This is where the nutrient exchange takes place
0:24:48 > 0:24:50between the fungus and the root.
0:24:54 > 0:24:58This nutrient exchange works both ways.
0:24:58 > 0:25:02The fungus feeds on sugars from the plant that it needs to grow
0:25:02 > 0:25:05and in return gives back water and minerals
0:25:05 > 0:25:08that the planet is unable to absorb enough of itself.
0:25:10 > 0:25:14I'm going to lift up this pine seedling here
0:25:14 > 0:25:17and you can see, where I'm pointing with my pinkie, that white fuzz.
0:25:17 > 0:25:19Oh, yeah, OK.
0:25:19 > 0:25:20Those are the fungal filaments
0:25:20 > 0:25:24and it is completely covering the roots of this pine tree right here.
0:25:26 > 0:25:29And it extends over a much larger surface area
0:25:29 > 0:25:31than the roots can possibly cover,
0:25:31 > 0:25:34and this gives them access to all kinds of nutrients
0:25:34 > 0:25:36and water, even, from the soil,
0:25:36 > 0:25:39so they can extract nitrogen and phosphorous, in particular,
0:25:39 > 0:25:41from the soil,
0:25:41 > 0:25:43and provide those to the plant,
0:25:43 > 0:25:46which the plant will then exchange for sugars
0:25:46 > 0:25:48that it produces through photosynthesis.
0:25:48 > 0:25:50And the two together make for a better plant?
0:25:50 > 0:25:53A better plant and a better fungus, healthier soil.
0:25:53 > 0:25:56So it's a win-win situation for both?
0:25:56 > 0:25:58It's a win-win situation for both partners
0:25:58 > 0:25:59and, in fact, for the entire world.
0:26:01 > 0:26:05'We're going to look for evidence of this vital relationship,
0:26:05 > 0:26:06'in the wild.'
0:26:06 > 0:26:08Well, we can't see them,
0:26:08 > 0:26:11but, all around us there are these unseen fungal partners.
0:26:11 > 0:26:15They're invisible to us when we just take a nice stroll along a path,
0:26:15 > 0:26:17but they're all around us.
0:26:17 > 0:26:19- Shall we have a go? - Let's do it.
0:26:21 > 0:26:22I think I've got some.
0:26:24 > 0:26:28Well, I mean, you don't have to search for it.
0:26:28 > 0:26:32- You can see the white tips here. - It's very obvious, yeah.
0:26:32 > 0:26:36But every one of these tiny little, side-branching roots
0:26:36 > 0:26:37is covered in fungus.
0:26:41 > 0:26:44There's a fascinating and fundamental relationship
0:26:44 > 0:26:46between fungi and land plants,
0:26:46 > 0:26:51not just here in Kew and every park in Britain, but in every field.
0:26:51 > 0:26:54Without this relationship, plants couldn't thrive.
0:26:54 > 0:26:57It's impossible to overstate its importance.
0:26:59 > 0:27:02So how exactly does this hidden process happen?
0:27:05 > 0:27:09To find out, Patrick has been capturing it in action,
0:27:09 > 0:27:12starting from the moment a spore hits the ground.
0:27:13 > 0:27:16The primary mission of a fungal spore is to feed
0:27:16 > 0:27:18and find food resources.
0:27:18 > 0:27:23Now, under the right conditions, the spore starts to germinate and grow.
0:27:23 > 0:27:26That's what we can see here. We've placed some spores
0:27:26 > 0:27:30into a drop of water and as you can see, they're starting to swell.
0:27:30 > 0:27:32There's a little bit of movement starting to go on inside.
0:27:32 > 0:27:35- Oh, yeah.- And already you can see this little bud emerging,
0:27:35 > 0:27:39and that little bud is the beginnings of a fungal hypha.
0:27:39 > 0:27:41So, what is a hypha?
0:27:41 > 0:27:44The hypha is the feeding part of a fungus, the feeding tube,
0:27:44 > 0:27:47and the hypha goes in search of water and food
0:27:47 > 0:27:49and will continue growing and branching
0:27:49 > 0:27:53until it eventually establishes a colony, a fungal colony.
0:27:53 > 0:27:54Does it grow very fast?
0:27:54 > 0:27:57Once a hypha finds its food source, it can develop very quickly
0:27:57 > 0:27:59and form what we call a mycelium.
0:28:01 > 0:28:06A mycelium is the scientific name for the fungus's feeding network.
0:28:06 > 0:28:09Here magnified 500 times,
0:28:09 > 0:28:13we can see one starting to form as many hyphae begin to web together.
0:28:14 > 0:28:17Essentially, it is a fungus's root system,
0:28:17 > 0:28:20a complex series of feeding tubes.
0:28:20 > 0:28:24It's not unlike a microscopic human digestive system,
0:28:24 > 0:28:26processing food that allows it to grow.
0:28:27 > 0:28:32Within these tubes are the nutrients that are a fungus's entire future.
0:28:32 > 0:28:34And you can see the network forming now.
0:28:34 > 0:28:36Yeah, and this is in the centre of the colony.
0:28:36 > 0:28:39You have this branched network that keeps on feeding nutrients
0:28:39 > 0:28:42through the colony and sharing its water and resources.
0:28:42 > 0:28:45And that's only half a millimetre square?
0:28:45 > 0:28:47Roughly half a millimetre is the sort of field of view
0:28:47 > 0:28:48that we're looking at here
0:28:48 > 0:28:50and it's very much like a road network -
0:28:50 > 0:28:52we've got these kind of main motorways,
0:28:52 > 0:28:54we've got lots of little side routes in there
0:28:54 > 0:28:58and we've got flow of nutrients, water and it's very dynamic.
0:28:58 > 0:29:00For example, if I was to break one of these tracks,
0:29:00 > 0:29:03the fungus would very quickly adapt and form new connections.
0:29:03 > 0:29:05- And form new connections and new routes.- Mmm.
0:29:05 > 0:29:08It's extraordinary how bustling it is.
0:29:08 > 0:29:10Of course I can now see what we saw with Bryn Dentinger -
0:29:10 > 0:29:14how efficient these hyphae are at gathering nutrients
0:29:14 > 0:29:16and moving through the soil.
0:29:16 > 0:29:19Absolutely, and even in the most dry soil environments,
0:29:19 > 0:29:22fungi are able to draw up the moisture from the soil
0:29:22 > 0:29:25and transfer it into the plants through this co-operation.
0:29:25 > 0:29:28It is extraordinary, extraordinary footage.
0:29:30 > 0:29:33Although the mycelium is almost entirely invisible to us,
0:29:33 > 0:29:36it makes up the vast majority of the organism.
0:29:37 > 0:29:40And its size can be truly breathtaking.
0:29:41 > 0:29:44So big, in fact, it can often extend for miles.
0:29:48 > 0:29:53The biggest organism in the world is not the blue whale,
0:29:53 > 0:30:00but a mycelium that spreads across an incredible 2,384 acres
0:30:00 > 0:30:02in Oregon's Blue Mountains.
0:30:03 > 0:30:07It's called Armillaria mellea, or the honey fungus,
0:30:07 > 0:30:11and this example is thought to be over 2,000 years old.
0:30:13 > 0:30:16It's a mind-boggling example of how far a mycelium can grow.
0:30:19 > 0:30:24But it also reveals just how destructive a feeding fungus can be.
0:30:25 > 0:30:28These are clumps of honey fungus.
0:30:28 > 0:30:31It's the same fungus that spread inexorably
0:30:31 > 0:30:34through the forests of Oregon
0:30:34 > 0:30:37and it demonstrates a very different, some would say sinister,
0:30:37 > 0:30:40relationship between mycelium and trees.
0:30:44 > 0:30:46Unlike the balanced nutrient exchange
0:30:46 > 0:30:50that we see between most fungi and their plant partners,
0:30:50 > 0:30:55honey fungus takes much more from its host than it gives.
0:30:55 > 0:30:58It consumes all the sugars it needs,
0:30:58 > 0:31:01but crucially doesn't give back enough water and nutrients
0:31:01 > 0:31:03to help the tree grow properly.
0:31:04 > 0:31:08As a result, the greedy mycelium of this fungus thrives,
0:31:08 > 0:31:11while the tree slowly weakens.
0:31:13 > 0:31:16Honey fungus is a slow killer.
0:31:16 > 0:31:20It advances from tree to tree on hidden threads.
0:31:20 > 0:31:23As our tree population ages and some sickens,
0:31:23 > 0:31:26the rise of honey fungus is inexorable.
0:31:29 > 0:31:33But it's not the biggest threat to our plants and trees.
0:31:33 > 0:31:37There's another species of fungus whose hunger is even more deadly.
0:31:39 > 0:31:42I've come to Norfolk to find evidence of a fungus
0:31:42 > 0:31:44that's very difficult to see,
0:31:44 > 0:31:46but whose eating habits
0:31:46 > 0:31:51are threatening to wipe out one of Britain's oldest trees.
0:31:51 > 0:31:55Just a few years ago, a new killer arrived in Britain -
0:31:55 > 0:31:56ash dieback disease,
0:31:56 > 0:32:00or Chalara fraxinea, to give it its scientific name.
0:32:00 > 0:32:03And no fungus better demonstrates
0:32:03 > 0:32:05the greed of mycelium for nourishment...
0:32:07 > 0:32:09..and if it has its way, maybe,
0:32:09 > 0:32:12magnificent forest trees like this ash
0:32:12 > 0:32:14may yet become just a part of history.
0:32:18 > 0:32:20David Bole knows all too well
0:32:20 > 0:32:23just how destructive this fungus has become.
0:32:23 > 0:32:26And there's quite a lot of dieback in here, isn't there?
0:32:26 > 0:32:28Yeah.
0:32:28 > 0:32:31This is one of the first woods where we discovered it.
0:32:31 > 0:32:35What we're finding now is that there's over 500 cases
0:32:35 > 0:32:39in the wider environment and as we do more in-depth surveys,
0:32:39 > 0:32:41more and more cases are coming to the fore.
0:32:41 > 0:32:43Take me through the symptoms.
0:32:43 > 0:32:47Well, the first thing to look for is this, the black leaves,
0:32:47 > 0:32:48which we've got here
0:32:48 > 0:32:53and we've got a really good example on this little, young tree here.
0:32:53 > 0:32:55The leaves have died but they're black.
0:32:55 > 0:32:58They really don't look healthy and they're hanging onto the tree.
0:32:58 > 0:33:00I notice they die from the top too,
0:33:00 > 0:33:03so they're dead up here but still green down here.
0:33:03 > 0:33:05Yes, you know, it's called dieback and that's a good way
0:33:05 > 0:33:08to think of it - we have the tree slowly dying back.
0:33:09 > 0:33:13Other symptoms are these diamond-shaped lesions.
0:33:13 > 0:33:17The fungus lands on the leaves, the mycelia come in,
0:33:17 > 0:33:21and works its way up and down the cells of the tree
0:33:21 > 0:33:25and forms these very particular diamond-shaped lesions.
0:33:27 > 0:33:31This process is rather eerily called necrotrophy,
0:33:31 > 0:33:33which means eating the dead.
0:33:33 > 0:33:35The feeding hyphae of ash dieback
0:33:35 > 0:33:37attach themselves to their tree hosts
0:33:37 > 0:33:39in the same way as other fungi,
0:33:39 > 0:33:43but they obtain their sugars without providing any nutrients
0:33:43 > 0:33:45or water in return.
0:33:46 > 0:33:49It's all one-way traffic
0:33:49 > 0:33:50and has a fatal outcome.
0:33:53 > 0:33:54OK.
0:33:54 > 0:33:56OK, so let's just have a look inside.
0:33:57 > 0:34:00Oh, yeah. You can see discolouration.
0:34:00 > 0:34:02It's absolutely patent.
0:34:02 > 0:34:06So the disease has entered here and this is the fungal mycelia,
0:34:06 > 0:34:09which are starting to work its way inside the tree.
0:34:09 > 0:34:11The mycelia get inside all the cells
0:34:11 > 0:34:14that transport the water up and down the tree
0:34:14 > 0:34:16and stop the water transport
0:34:16 > 0:34:19and so the tree effectively dies of thirst, if you like.
0:34:26 > 0:34:30It's a sad end to one of our most beautiful and elegant forest trees.
0:34:30 > 0:34:32It really, really is, yes.
0:34:32 > 0:34:35I mean, we'll probably lose a generation of ash
0:34:35 > 0:34:37but let's hope we see that coming back.
0:34:40 > 0:34:44Ash dieback demonstrates just what happens when the delicate balance
0:34:44 > 0:34:47between plant and fungus gets out of kilter...
0:34:48 > 0:34:50..and that's what allows this disease
0:34:50 > 0:34:52to spread so far and so fast.
0:34:55 > 0:34:59It also shows just what a voracious eater fungal mycelium can be.
0:35:01 > 0:35:03But though this unstoppable appetite
0:35:03 > 0:35:05can be deadly in the natural world,
0:35:05 > 0:35:10some scientists are looking to turn it to our advantage.
0:35:24 > 0:35:29This is Eben Bayer, an entrepreneur based in New York.
0:35:29 > 0:35:32He noticed something intriguing that happens
0:35:32 > 0:35:36when some mycelium spreads out in search of food.
0:35:39 > 0:35:41First time I saw mycelium in action was holding
0:35:41 > 0:35:44clumps of woodchips together on my family farm
0:35:44 > 0:35:46and rather than falling apart,
0:35:46 > 0:35:49they'd be held together by these white fibre strands.
0:35:49 > 0:35:52One night, sitting at home on my futon in my apartment,
0:35:52 > 0:35:56I got this crazy idea about, "Hey, mycelium seems to grow,
0:35:56 > 0:35:58"and glue the forest floor together.
0:35:58 > 0:36:00"Maybe we can use it as a glue."
0:36:03 > 0:36:07Eben saw huge potential in this binding property of mycelium.
0:36:07 > 0:36:10He used it to create a new kind of packaging,
0:36:10 > 0:36:13one that he believes could, ultimately,
0:36:13 > 0:36:16become an eco-friendly alternative to some plastics.
0:36:18 > 0:36:21Just in packaging alone, there's like billions of dollars
0:36:21 > 0:36:23of Styrofoam used every year,
0:36:23 > 0:36:27somewhere between 3.5 and 5 billion of styrene,
0:36:27 > 0:36:30and the biggest issue with plastics is at their end of life
0:36:30 > 0:36:33and with our material, you get something that,
0:36:33 > 0:36:35at the end of its useful life, can be composted, right.
0:36:35 > 0:36:39Your packaging becomes a nutrient for your neighbourhood, not a pollutant.
0:36:41 > 0:36:45To make his new material, Eben mimics what happens in nature.
0:36:46 > 0:36:50He takes some ground corn stalks and seeds them with fungus spores.
0:36:50 > 0:36:54The spores germinate, and begin to feed on the stalks,
0:36:54 > 0:36:59breaking down and digesting them, so the mycelium can start to grow.
0:36:59 > 0:37:03The mixture is then placed inside a mould and left
0:37:03 > 0:37:06for the mycelium to perform its biological magic.
0:37:07 > 0:37:11So, they'll sit on a rack like this for anywhere from 24 to 72 hours.
0:37:11 > 0:37:13It doesn't look like anything's happening,
0:37:13 > 0:37:15but the mycelium is already going to work,
0:37:15 > 0:37:18growing and extending out from every one of these particles
0:37:18 > 0:37:20and building a strong, tough network.
0:37:20 > 0:37:23And within 24 hours, this part will look a little white
0:37:23 > 0:37:25and that's the mycelium gluing everything together.
0:37:32 > 0:37:34So this is a finished corner block.
0:37:34 > 0:37:37It's been grown in our production process, it's been moulded
0:37:37 > 0:37:41and all of this came from that loosie-goosie agricultural by-product
0:37:41 > 0:37:42you saw at the beginning.
0:37:42 > 0:37:44Pretty incredible, huh?
0:37:49 > 0:37:51What we've done with mycelium here,
0:37:51 > 0:37:53which is basically leveraging a living organism
0:37:53 > 0:37:55to create really great technology,
0:37:55 > 0:37:57is where the excitement is, that's where the innovation is
0:37:57 > 0:38:00and that's where the solutions are going to be for the next 100 years.
0:38:03 > 0:38:07So the mushroom mycelium could help us tackle the global problem
0:38:07 > 0:38:09of plastic waste.
0:38:09 > 0:38:12But Eben's work also demonstrates another important trait
0:38:12 > 0:38:14of the feeding mycelium.
0:38:16 > 0:38:19While some fungi feed on living organisms,
0:38:19 > 0:38:23others only eat those that are dead.
0:38:23 > 0:38:27These fungi are able to break down and digest organic waste
0:38:27 > 0:38:30and in doing so, recycle it.
0:38:31 > 0:38:34This process is called saprotrophy
0:38:34 > 0:38:38and it's absolutely vital in the natural world.
0:38:39 > 0:38:42In this damp wood, the litter of leaves,
0:38:42 > 0:38:46indeed, every twig, is being consumed by mycelium,
0:38:46 > 0:38:50that breaks down the cellulose and other compounds.
0:38:50 > 0:38:51Even...
0:38:52 > 0:38:54Even wood can be digested by fungi.
0:38:54 > 0:38:58The hard lining that gives the wood its strength
0:38:58 > 0:39:03can be consumed and the wood reduced to little more than rubble.
0:39:03 > 0:39:07Were it not for the relentless activity of mycelium, in fact,
0:39:07 > 0:39:13the whole planet would be covered with a mass of undigested scrub.
0:39:17 > 0:39:21It's hard to overstate the importance of saprotrophic fungi.
0:39:21 > 0:39:25They have successfully recycled the world's natural waste
0:39:25 > 0:39:28for hundreds of millions of years,
0:39:28 > 0:39:32making entire ecosystems habitable for animal and plant life.
0:39:33 > 0:39:36So how do they achieve this crucial trick?
0:39:39 > 0:39:42So, Patrick, let's talk rot.
0:39:42 > 0:39:44Few people realise just how important
0:39:44 > 0:39:48those saprotropes fungi are in nature.
0:39:48 > 0:39:49How does it work?
0:39:49 > 0:39:51Well, fungi are really quite invasive.
0:39:51 > 0:39:55The fungi have this mycelium, which penetrates deep into the waste
0:39:55 > 0:39:57and unlike us, where our stomachs are internal,
0:39:57 > 0:40:01the fungi secrete their digestive juices out into the environment
0:40:01 > 0:40:04and start breaking down the complex molecules,
0:40:04 > 0:40:07things like cellulose, into more simple forms.
0:40:07 > 0:40:10This is via a myriad of those little hyphal threads.
0:40:10 > 0:40:11That's right.
0:40:11 > 0:40:14And to demonstrate just how effective saprotrophic fungi are
0:40:14 > 0:40:16at breaking down organic matter,
0:40:16 > 0:40:19I've put several days of kitchen waste into this beaker
0:40:19 > 0:40:21and I've filmed it over two weeks
0:40:21 > 0:40:24to see just how quickly it goes down, it rots down.
0:40:25 > 0:40:28SQUELCHING
0:40:29 > 0:40:32So there it is, just sort of sinking down.
0:40:32 > 0:40:35Yeah. Lots of juice exuding from the vegetables.
0:40:35 > 0:40:39So the invisible threads of the mycelium are getting in there,
0:40:39 > 0:40:42breaking vegetables and the other organic waste,
0:40:42 > 0:40:43into something they can use.
0:40:45 > 0:40:47The other important thing to note here
0:40:47 > 0:40:49is that when all these vegetables did go into the beaker,
0:40:49 > 0:40:52they already had spores on them, so they were already pre-seeded
0:40:52 > 0:40:54- with the spores. - Because spores are everywhere.
0:40:54 > 0:40:57Exactly, when you bring the food back from the supermarket,
0:40:57 > 0:41:00it'll already have a coating of a whole cocktail of different spores
0:41:00 > 0:41:03and as soon as those fungi are in a slightly warm environment,
0:41:03 > 0:41:05it becomes quite a feeding frenzy, if you like.
0:41:09 > 0:41:13So, Richard, I'm going to show you the results of the one
0:41:13 > 0:41:15that I prepared two weeks ago.
0:41:16 > 0:41:19Well, it couldn't be much clearer than that.
0:41:19 > 0:41:22Yeah. Look how far it's gone down. This was the start point and...
0:41:22 > 0:41:24At least a third.
0:41:24 > 0:41:27..it's gone down about a third and I'd expect, within another two weeks,
0:41:27 > 0:41:28to be almost to the bottom.
0:41:28 > 0:41:30If this process wasn't happening
0:41:30 > 0:41:33we would just be surrounded by organic waste matter.
0:41:33 > 0:41:35- Heaps of vegetables.- Exactly.
0:41:35 > 0:41:38What it does show is just what makes the fungi
0:41:38 > 0:41:43such efficient seekers after... scavengers after nutrition.
0:41:43 > 0:41:45Yep.
0:41:45 > 0:41:47Extraordinary.
0:41:47 > 0:41:50The brilliant way the mycelium of a saprotrophic fungus
0:41:50 > 0:41:55uses digestive juices just like humans to break down waste
0:41:55 > 0:41:59makes it a recycling machine like no other.
0:41:59 > 0:42:02And it doesn't stop there.
0:42:02 > 0:42:05For as saprotrophic fungi recycle organic matter,
0:42:05 > 0:42:09they're performing a key role in creating healthy soil,
0:42:09 > 0:42:14soil that can, in turn, sustain new plant life
0:42:14 > 0:42:18and that's also a home for a host of other life forms,
0:42:18 > 0:42:21tiny micro-organisms that live within it.
0:42:22 > 0:42:23And for some fungi,
0:42:23 > 0:42:28the arrival of these new guests is just another feeding opportunity.
0:42:30 > 0:42:33These oyster mushrooms, or Pleurotus,
0:42:33 > 0:42:38have mycelium that breaks down the wood in rotting logs.
0:42:39 > 0:42:41They're quite efficient at doing this,
0:42:41 > 0:42:45but they have a shortage of one essential element, nitrogen
0:42:45 > 0:42:47and to make good this deficiency,
0:42:47 > 0:42:49they've evolved a very special trick.
0:42:54 > 0:42:56From the end of some of its hyphae,
0:42:56 > 0:42:59the oyster mushroom emits tiny lassos
0:42:59 > 0:43:01that secrete a powerful toxin.
0:43:01 > 0:43:03And it does this for one reason...
0:43:05 > 0:43:07..nematode worms.
0:43:07 > 0:43:10These tiny organisms live within the logs
0:43:10 > 0:43:12and happen to be rich in the nitrogen
0:43:12 > 0:43:14that the hungry mushroom needs.
0:43:15 > 0:43:19The oyster mushroom lures the nematodes towards their tiny lassos
0:43:19 > 0:43:20before enveloping them.
0:43:22 > 0:43:25Once trapped, it's curtains for the little worm,
0:43:25 > 0:43:27and dinner for the mushroom
0:43:27 > 0:43:30as it gets the nitrogen-rich fluid it needs.
0:43:32 > 0:43:36The oyster mushroom's rather gruesome feeding trick
0:43:36 > 0:43:41demonstrates yet again just how sophisticated a fungus can be
0:43:41 > 0:43:43when it comes to getting the food it needs.
0:43:49 > 0:43:53It's a talent that, once again, we humans are looking to harness.
0:43:56 > 0:44:00Over in Washington State, mycologist Paul Stamets
0:44:00 > 0:44:03has turned to our hungry friend the oyster mushroom,
0:44:03 > 0:44:06in the hope he can use it on a truly grand scale -
0:44:06 > 0:44:10to tackle some of our most pressing environmental problems,
0:44:10 > 0:44:12such as chemical pollution.
0:44:15 > 0:44:20One of my great realisations in life is that habitats have immune systems
0:44:20 > 0:44:21just like we do,
0:44:21 > 0:44:25but mushrooms are the bridges between the two.
0:44:25 > 0:44:29These things unravel and break down large molecules into smaller ones
0:44:29 > 0:44:32that are very useful for other members in the ecological community.
0:44:33 > 0:44:38The course of that decomposition, has many different properties
0:44:38 > 0:44:40that we can use for breaking down toxic waste.
0:44:42 > 0:44:43That looks good.
0:44:43 > 0:44:46Paul discovered that mushroom mycelium
0:44:46 > 0:44:50can break down the hydrocarbons present in much chemical waste.
0:44:50 > 0:44:53It's a process he calls bioremediation.
0:44:53 > 0:44:57The mushroom is greedily eating the pollutants away.
0:45:05 > 0:45:07It looks convincing in the lab,
0:45:07 > 0:45:10but does it work in practice?
0:45:10 > 0:45:14Paul's theory was recently put to the test on an industrial level
0:45:14 > 0:45:16when a heavily-polluted petrochemical site
0:45:16 > 0:45:19was seeded with oyster mushroom mycelium.
0:45:21 > 0:45:23The work was carried out by environmental engineer
0:45:23 > 0:45:24Howard Sprouse.
0:45:26 > 0:45:28Yeah, bring her down a little for me.
0:45:28 > 0:45:32After just two days, the team found that their polluted pile
0:45:32 > 0:45:36had been transformed by the mushroom mycelium
0:45:36 > 0:45:38and was now teeming with new life.
0:45:39 > 0:45:44Well, this is interesting. We've got lots of worms in here now.
0:45:44 > 0:45:46That's a good sign.
0:45:46 > 0:45:50If it drops any more, we're going to be able to use this soil anywhere.
0:45:52 > 0:45:54The contaminate has gone...
0:45:55 > 0:45:59..the decomposition process that the fungi have started
0:45:59 > 0:46:03is continued by other soil microorganisms
0:46:03 > 0:46:07and you end up with soil that's richer than it was when you started.
0:46:11 > 0:46:14Paul's study shows that oyster mushroom mycelium
0:46:14 > 0:46:17can not only digest chemical waste -
0:46:17 > 0:46:20it also manages to create an entirely new ecosystem
0:46:20 > 0:46:22in the process.
0:46:22 > 0:46:27At a time when the Earth is suffering from toxin exposure,
0:46:27 > 0:46:32erosion of habitats, overpopulation,
0:46:32 > 0:46:35deforestation, loss of soil integrity...
0:46:37 > 0:46:41..mushrooms present themselves with unique properties
0:46:41 > 0:46:46that can address all those problems with a single group,
0:46:46 > 0:46:48and that's what I find so exciting -
0:46:48 > 0:46:51that the solutions are literally underfoot.
0:46:54 > 0:46:57Paul's work shows just how great
0:46:57 > 0:46:59the potential of fungus mycelium might be.
0:47:01 > 0:47:05Its hidden underground threads act upon their natural environment
0:47:05 > 0:47:09in truly remarkable ways we are only now beginning to realise.
0:47:12 > 0:47:14But as vital as it could be to us,
0:47:14 > 0:47:17the mycelium's feeding quest has one simple goal...
0:47:19 > 0:47:21..to produce its fruiting body...
0:47:22 > 0:47:25..bringing the organism to the end of its life cycle.
0:47:31 > 0:47:35We've seen how mycelium can form complex feeding webs
0:47:35 > 0:47:38and how the mycelium underpins so many of Earth's ecosystems...
0:47:40 > 0:47:44..yet that mycelium itself has only one purpose...
0:47:45 > 0:47:51..to fulfil its own life cycle and to lead once again to the mushroom.
0:47:59 > 0:48:03For the fungus, this final stage simply means reproduction
0:48:03 > 0:48:06and the dispersal of billions of spores.
0:48:07 > 0:48:09'But for another species,
0:48:09 > 0:48:12'it's just the beginning of its relationship with fungi.'
0:48:12 > 0:48:13Nice find.
0:48:13 > 0:48:16'And that species is us.'
0:48:16 > 0:48:17Ah.
0:48:17 > 0:48:19The sulphur tuft.
0:48:19 > 0:48:20Very abundant.
0:48:21 > 0:48:23Very inedible.
0:48:23 > 0:48:26'Its mythical status in folklore and magic
0:48:26 > 0:48:30'has made the mushroom an object of both fascination and fear.'
0:48:30 > 0:48:33Well, now, this is a troublemaker.
0:48:34 > 0:48:37'And sometimes that fear can be for good reason.'
0:48:38 > 0:48:42Poison pie is, as its name suggests, not a good thing to eat.
0:48:46 > 0:48:47Go out into any woodland
0:48:47 > 0:48:51and you're likely to encounter a wide range of poisonous fungi
0:48:51 > 0:48:54that you certainly would not want on your dinner plate.
0:48:54 > 0:48:57People get a big nervous about this one...
0:48:57 > 0:48:59the Sickener.
0:48:59 > 0:49:02Well, the name tells you everything. You don't want to eat it.
0:49:05 > 0:49:07The notion that fungi can be poisonous
0:49:07 > 0:49:09is what frightens us most about them.
0:49:13 > 0:49:17This is the most poisonous mushroom known to man.
0:49:17 > 0:49:19It's the death cap.
0:49:19 > 0:49:22People have eaten it, apparently in mistake for a field mushroom.
0:49:22 > 0:49:23I can't think how.
0:49:23 > 0:49:28But they'd have cause to regret it, because half a cap of one of these
0:49:28 > 0:49:30is enough to kill a grown man,
0:49:30 > 0:49:32and slowly,
0:49:32 > 0:49:33and painfully.
0:49:38 > 0:49:40I've been a field mycologist for many years
0:49:40 > 0:49:45and know to avoid dangerous mushrooms like the death cap,
0:49:45 > 0:49:49but their toxicity does raise an interesting question -
0:49:49 > 0:49:52what is it that gives mushrooms the power to kill?
0:49:54 > 0:49:57To explore this, I've come back to the lab once final time.
0:49:59 > 0:50:03Every fungus will have a cocktail of different chemicals within it,
0:50:03 > 0:50:06and depending on what type it is, there's various different types
0:50:06 > 0:50:10of poisonous chemicals which are present in these mushrooms.
0:50:10 > 0:50:14Possibly one of the worst ones is something like the destroying angel.
0:50:14 > 0:50:16Or the death cap, which is its close relative.
0:50:16 > 0:50:19Or the death cap, and those have a substance called amatoxins,
0:50:19 > 0:50:22which are deadly toxic.
0:50:22 > 0:50:25You'd only have to eat one or two of these to be completely poisoned.
0:50:25 > 0:50:29You'll end up with liver failure, kidney failure and death
0:50:29 > 0:50:32and it's a really quite nasty way to go.
0:50:32 > 0:50:37So we know that mushrooms are toxic, but why are they toxic?
0:50:37 > 0:50:40Well, there's a theory that mushrooms evolved to become toxic
0:50:40 > 0:50:43in order to discourage predators from eating them,
0:50:43 > 0:50:45but I'm not sure that's exactly the case,
0:50:45 > 0:50:49so I've set up a little test with a selection of mushrooms
0:50:49 > 0:50:52and we've brought in a guest to do the test for us.
0:50:55 > 0:51:00Patrick has offered a selection of five mushrooms to a hungry slug,
0:51:00 > 0:51:02one of which is poisonous to humans.
0:51:02 > 0:51:04But which will it prefer?
0:51:06 > 0:51:08After a look around and having a nibble of one or two,
0:51:08 > 0:51:10he seems to have settled on this one.
0:51:10 > 0:51:13Oh, the sulphur tuft, which is famously bitter and poisonous.
0:51:13 > 0:51:15Yeah, it doesn't seem to bother the slug
0:51:15 > 0:51:19and, in fact, he seems to be having a tasty meal on the gills, there.
0:51:19 > 0:51:23So what we've seen is certainly not in support of the idea
0:51:23 > 0:51:26that fungi are kind of protecting themselves from being eaten
0:51:26 > 0:51:29until mature. In fact, you could argue that that mushroom
0:51:29 > 0:51:31actually wants to be eaten,
0:51:31 > 0:51:34so what's it all about?
0:51:34 > 0:51:36I think, really, the bigger picture
0:51:36 > 0:51:38is the diversity within the fungal kingdom,
0:51:38 > 0:51:42in that the fungi produce thousands of different chemicals
0:51:42 > 0:51:45and it just so happens that some of those are toxic to us,
0:51:45 > 0:51:48whereas they might not be toxic to something like a slug or an insect.
0:51:48 > 0:51:51In fact, it may be a very important food source for those animals.
0:51:51 > 0:51:55So you've just got a huge spectrum of different types of chemicals.
0:51:55 > 0:51:57And we're only just beginning to explore
0:51:57 > 0:51:59- the implications of some of these. - Absolutely.
0:52:02 > 0:52:05We don't yet fully understand why some fungi
0:52:05 > 0:52:07have such a potent effect on us.
0:52:07 > 0:52:09More research is needed.
0:52:10 > 0:52:13But, already, we're beginning to exploit
0:52:13 > 0:52:17some of their seemingly sinister behaviours for our own benefit.
0:52:18 > 0:52:20Can I introduce you to cordyceps?
0:52:20 > 0:52:24These are dried specimens of a very famous fungus,
0:52:24 > 0:52:28famous in Chinese medicine for curing all manner of ills.
0:52:28 > 0:52:31It's a curious fungus with a strange, parasitic lifestyle.
0:52:35 > 0:52:39Unlike most fungi, it doesn't feed on dead matter
0:52:39 > 0:52:41but instead seeks out a very different host.
0:52:43 > 0:52:46Like something out of science fiction,
0:52:46 > 0:52:49this fungus grows inside insects,
0:52:49 > 0:52:53slowly killing them until the fruiting body is ready to emerge.
0:53:01 > 0:53:05But despite its rather, alien life habits,
0:53:05 > 0:53:08the chemicals concealed inside the cordyceps
0:53:08 > 0:53:11may yet prove crucial to a major medical breakthrough.
0:53:14 > 0:53:18Doctor Cornelia De Moor from the University of Nottingham
0:53:18 > 0:53:21is using this little mushroom in a cutting-edge treatment
0:53:21 > 0:53:24for one of our most feared diseases -
0:53:24 > 0:53:25cancer.
0:53:28 > 0:53:34So in cordyceps there are very high levels of this cordycepin.
0:53:35 > 0:53:36And cordycepin is a compound
0:53:36 > 0:53:38that is actually only very slightly changed
0:53:38 > 0:53:43from a very common compound that you find in all cells called adenosine.
0:53:43 > 0:53:45It's only one oxygen difference.
0:53:45 > 0:53:48But for some reason, only cordyceps fungi make cordycepin
0:53:48 > 0:53:51while all organisms make adenosine.
0:53:53 > 0:53:57This unique compound produced by cordyceps has long been of interest
0:53:57 > 0:54:02to alternative medicine in the treatment of cancerous tumours.
0:54:02 > 0:54:06But how it worked was never clear and Cornelia was keen to find out.
0:54:10 > 0:54:13What surprised us immensely the first time we treated cells
0:54:13 > 0:54:17with cordycepin is when we put cordycepin on cells like that,
0:54:17 > 0:54:20they changed shape into cells like that
0:54:20 > 0:54:26in which the little grains are gone and the cells start to shrink.
0:54:26 > 0:54:28So when we saw this,
0:54:28 > 0:54:31we knew there was something quite fundamental happening to the cells
0:54:31 > 0:54:34and that then led to our later discoveries
0:54:34 > 0:54:36on the affects of cordycepin.
0:54:41 > 0:54:43Cornelia knew that with any cancer,
0:54:43 > 0:54:47in order for the individual cells to multiply and grow,
0:54:47 > 0:54:49they must join themselves together
0:54:49 > 0:54:53using tiny stems called poly-A tails.
0:54:53 > 0:54:56And it's here that she has discovered that cordycepin
0:54:56 > 0:54:57plays a crucial role.
0:54:59 > 0:55:02So we've been doing some work on breast cancer cells,
0:55:02 > 0:55:04which we've been treating with cordycepin,
0:55:04 > 0:55:08and what we're seeing is that the cordycepin appears to stop
0:55:08 > 0:55:10the making of the long poly-A tail.
0:55:10 > 0:55:12So it might not kill the cell
0:55:12 > 0:55:17but the most important thing - it stops the growth of the cancer cell,
0:55:17 > 0:55:21by cutting off the machinery that is necessary for cell growth.
0:55:23 > 0:55:26It is a completely new mechanism for a cancer drug,
0:55:26 > 0:55:30so all other cancer drugs work on completely different principles,
0:55:30 > 0:55:32not on inhibiting this polyadenylation,
0:55:32 > 0:55:36so it could be the first of a new class of drugs,
0:55:36 > 0:55:39not only for cancer, but also for inflammatory diseases.
0:55:42 > 0:55:45Medical breakthroughs, from Fleming's penicillin
0:55:45 > 0:55:49to cutting edge cancer research, reveal an extraordinary truth.
0:55:50 > 0:55:53The cells of fungi have the ability
0:55:53 > 0:55:56to interact with our own cells on a profound level...
0:55:59 > 0:56:03..to alter them in ways that affect our health, even our survival.
0:56:05 > 0:56:07And this is a powerful clue
0:56:07 > 0:56:11to the true relationship between fungi and us.
0:56:11 > 0:56:15Time and again, we seem to discover deep biological connections
0:56:15 > 0:56:17between ourselves and the fungi.
0:56:19 > 0:56:21But what could we have in common with a mushroom?
0:56:23 > 0:56:25To find out the answer, we have to delve deep
0:56:25 > 0:56:28into our own evolutionary history.
0:56:30 > 0:56:35As we've seen, fungi are neither plant nor animal.
0:56:35 > 0:56:37Early in the story of life on Earth,
0:56:37 > 0:56:42they established themselves as a kingdom in their own right.
0:56:42 > 0:56:46But it's the moment when this happened that is truly significant.
0:56:48 > 0:56:51At the point when plants and animals diverged,
0:56:51 > 0:56:54the fungi were still part of that animal branch.
0:56:56 > 0:56:58It was not until about ten million years later
0:56:58 > 0:57:01that they began their own evolutionary journey
0:57:01 > 0:57:02as a distinct kingdom.
0:57:03 > 0:57:08This explains why they have retained a number of key biological traits
0:57:08 > 0:57:12that make them much more animal than plant, much more like us.
0:57:15 > 0:57:18Traits we've seen time and time again,
0:57:18 > 0:57:21as we've explored their fascinating life cycle...
0:57:22 > 0:57:25..from the explosive way that they release their spores...
0:57:27 > 0:57:31..to the way they feed and digest other organisms, much as we do.
0:57:33 > 0:57:34At every stage of their life,
0:57:34 > 0:57:38fungi reveal just how much like us they are.
0:57:38 > 0:57:41It's a powerful connection, that explains why we work
0:57:41 > 0:57:43so well together.
0:57:43 > 0:57:47So we are all much more mushroom than you could ever imagine.
0:57:48 > 0:57:53And because of this close affinity, sometimes the fungi work with us,
0:57:53 > 0:57:55and even sometimes against us...
0:57:56 > 0:57:59..and that is the true magic of mushrooms.