[Wind and bird calls can be heard and the CSIRO logo and text appears: Rust, The Fungi that Destroy Plants]
[Image changes to show green wheat heads waving in the wind]
Narrator: Plants are under constant threat from invaders.
[Camera zooms in on a single wheat stem]
This wheat crop stem is being attacked by a parasite.
[Camera continues to zoom in on a rust spot on the side of the stem and then the image shows a red penetration tube growing from the rust spot]
The parasite is called rust, although it is actually a type of fungus.
[Music plays and the image shows the red penetration tube continuing to grow and then the image shows the wheat stem rotating in an clockwise direction]
[Image changes to show an animation of the inside of a wheat stem with a red penetration tube running between the cells]
The invading rust fungus has penetrated deep inside the plant tissue.
[Music plays and the image shows the red penetration tube extending throughout the plant and then the camera pans to the left to show red spores pushing through the side of the plant]
As the invasion progresses the fungus produces spores. These spores erupt from the surface of the plant.
[Music plays and then the camera zooms out to show the spores on the surface of the plant]
The spores spread creating pustules, new sites of infection.
[Music plays and the image shows small red dots blowing from the plant and moving across the screen to the right and the image shows the plant with red fungal growth over the stem surface]
Soon the plant’s stem and leaves are covered in fungal growth.
[Music plays and the image changes to show the fungal spores moving across the screen from the left to the right]
Carried by wind the fungal spores can travel great distances
[Image changes to show a fungal spore attaching to the surface of a wheat stem]
eventually reaching other potential hosts.
[Music plays and the image shows the spore sending out a red penetration tube down the stem of the plant and entering through a small hole in the plant’s surface]
This spore must now find the nutrients it requires to grow. Sending out the germ tube it seeks an entry point into the plant.
[Music plays and the plant stem rotates in a clockwise direction and then the image shows the red penetration tubes moving inside the plant]
A newly formed penetration tube breaks inside the stem and the fungus extends further into the plant.
[Music plays and the camera zooms in on the red penetration tube moving inside of the plant and then the image shows hastorium penetrating through a cell wall inside the plant]
Once inside the stem, another structure called the haustorium is used to penetrate inside one of the plant’s cells.
[Music plays and the image shows blue dots absorbing into the hastorium]
The fungus can now take nutrients from within the plant.
[Music plays and the image shows red dots emanating from the hastorium and then the camera zooms in on the red dots and then shows green dots]
It also begins to secrete small protein molecules called effectors.
[Music plays and the camera zooms in on the green and red dots]
This is a critical time for the plant. If it can detect the fungal effector proteins it can try to stop the invasion.
[Music plays and the camera zooms in to show a green dot binding to a red dot]
The plant has specialised resistance proteins which act like an immune system.
[Music plays and the camera zooms out to show lots of green dots binding to red dots]
The resistance proteins can bind to the fungal effector proteins.
[Music plays and the image changes to show the hastorium inside the plant cell]
This binding event alerts the plant that an infection is taking place.
[Music plays and the image shows the cell wall containing the hastorium collapsing in]
Now that the parasite is detected the infected cells are sacrificed cutting off the energy supply to the invader.
[Music plays and the image shows the red penetration tube shrivelling up]
The fungus will eventually starve and the plant can continue to grow.
[Music plays and the image changes to show a plant stem with fungi attached to it and then two photographs appear of plants containing fungi]
New strains of fungi are constantly developing through evolution.
[Image changes to show a plant leaf with fungi on it and a plant leaf without fungi and text appears: Vulnerable, resistant]
This can make some plants vulnerable to infection.
[Music plays and the image changes to show rust on wheat stems]
Diseases like rust fungus have plagued crop production since people first began farming.
[Image changes to show a header moving over a crop of wheat]
Globally, infections of rust destroy 15 million tonnes of wheat each year.
[Image changes to show an aerial view of a seeder moving over a ploughed paddock]
Because of this wheat breeders must vigorously seek new sources of resistance to protect crops.
[Image changes to show spores and red penetration tubes through the cells of a plant and then the image moves to the right of the screen and the image changes to show wheat heads waving in the wind]
Perhaps by investigating the interactions between plants and their invaders we could one day prevent the devastation caused by rust fungi.
[Music plays and CSIRO logo and text appears: Created by Chris Hammang, Producer Sean O’Donoghue, Scientific Consultant Peter Dodds, Music and Sound Design, Richard Tamplenizza, Brooke Trezise,@Broken Yellow]
[Text appears: Special Thanks, Jenny Vuong, Benedetta Frida Baldi, Julian Heinrich, Ludovic Autin, Software Blender, ePMV, Funding CSIRO, learn more at www.csiro.au]
[CSIRO logo and text appears: Australia’s innovation catalyst]