http://www.bbc.co.uk/programmes/b09r3nwl
I particularly liked the moment when one of the fungi experts, sourced by BBC radio 4, announced that they were everywhere ‘Yes, even here in the BBC studio there would be fungal spoors floating around.
What are they up to asked Melvyn Bragg a little more animated than usual.
Looking to find a suitable substrait to colonise. Skin for example.’
The fruiting body is just the tip of the ice-burg. Underneath the mass of mycelium, feeds as a network.
Linnaeus first classifying – in to plant category. But neither animal or plant and both. They have in common chitin in their cell walls as do animals like invertebrates. Like animals they have foraging behaviour. Like plants they do not wander around. Unlike plants and like animals, they cannot make their own food.
Critical role in life on earth. Hugely important in the greening of the earth. Fossil evidence the Rhynie chert (Aberdeen)
140,000 know the names, 2.8-5million we do not know.
Fungal diseases of crops
Not bacteria or virus, as with humans, crop diseases no 1 is fungal. Despite fungicide pesticide spraying 10-20% crop lost through fungal attack when growing, then 5% post harvest a further. That’s a quarter.
Mycorrhizal– where fungus associated with the roots of plants. Fungi spread out their fine filaments through soil. They protect plant root from pathogens.
Garbage disposal agent of the natural world. By breaking down release nutrients, so giving nutrient to plant/trees around.
Endophytes – fungi living within plant without causing apparent disease. Some make chemicals which deter grazers like aphids. Some enable plants to live in saline soils.
Classification based on modes of nutrition: External digestion, secrete enzymes outside to break down. Decomposing stuff to get carbon (of cellulous) or growth limiting nutrients like nitrogen or phospherous.
Saprophytes – fungi which obtain nutrients directly from dead organic matter
Mycorrhizal – dependent
Parasitic – doing harm to host organism, eg
Irish potato famine – the blight is called by Phytophthora, fungus like. 1860’s. Due to great poverty, they effectively spread a monoculture (dividing the precious tuber into many parts to form the root of next years crop, year after year)
Life cycle – eg mushroom. produced billions of spoors, blown around or moved by invertebrates. If good conditions, germinate. Starts secreting enzymes, feeding itself. Then find a mate. The hypha come together and fuse. Fungi have hundreds of sexes they can fuse with. To stat with one nucleus. Mating means two. When conditions right, mushroom form. They can also reproduce asexually. Just separate out.
How come they haven’t taken over the planet. In a sense they have. They are also under attach. By animals who live in the soil.
Networks and connections. Vast networks key feature. Mycorrhizal fungi inparticular Mycellium develops through soil. Some Mycorrhizal can colonise multiple plants simultaneously some of different species So there is a potential for resources to move between those plants via the microral network. Eg orchids, many have lost the ability to produce their own carbon, and are entirely dependent on fungi to facilitate growth. These networks can also transfer other molectles. eg if under attack by aphides, they can signally molecules to alert and generate to neighbouring plants to activate their own defence mechanism before they are under attack.
As the seedlings root grows down into the soil, it releases a cocktail of chemicals. Sugars, amino acids and nutrients, an attractive meal for soil bacteria and funghi. The mycorrhizal fungus is just one of a crowd but the plant root also releases chemicals called flavenoids. They act as a signal and the microrysal fungus is more sensitive to its message than other organisms. Under the influence of flavenoids the fungus grows towards the root. A subtle molecular conversation starts to take place.
Closer in, a new chemical vocabulary comes into play. Cytocynins tells the fungus to branch. Now it’s the turn of the fungus to release a chemical. It in turn communicates with the plant. In response the plant switches off its natural defences. And the root hairs now redundant disappear. The fungus has now been recognised. The stage is set for the formation of a fully-fledged mycorrhizal partnership.
In microcosm this is what happens in a forest. A baby plant joins a larger one, which already has a mycorrhizal network.
Click to access s204-funghi-mutual-benefits.pdf
Fungi bad news eg Trees. The landscape was changing eg Dutch Elm disease from imports from Onatario. Then chestnut blight in the US. Today Ash Die Back probably from Poland from nursary in Buckenham.
Human health impact. Many suffer from skin infections. A million people die from fungal infections more than malaria.
Most important agent of crop disease. Wheat Maze and Rice cover 40% of global agricultural land. Various diseases. Very significant losses.
Imagine life without blue cheese, wine and beer. We like eating fungi they do useful things to food. Wheat barley all exist with fungi symbiosis. Power of fungi to grow sustainable crops
Manipulate fungi – to kill the organisms we consider pests.
Climate change – fungi are on the move in consort with climate change. Moving pole wards at a rate of 7 kilometers a year. Marching. Will effect crops we grow. We will probably change our crops. Honey moon period before pathogens catch up.
Kaliwood 