Fungal Diseases (AQA GCSE Combined Science: Trilogy: Biology): Revision Note

Fungi: Basics

• Some fungi are unicellular - as in the case of yeast -but others are multicellular, made up of thread-like structures called hyphae

  • The hyphae can grow and penetrate the surface of plants and animals causing infections

  • The hyphae can produce spores, which can spread the infection to other organisms

• Few fungal diseases affect humans

  • One example is athlete's foot which is spread by contact with surfaces that have been touched by an infected person, such as shower room floors

• Fungal infections are more common in plants and can destroy a crop or plant

Rose black spot

• Rose black spot is a fungal disease of plants where purple or black spots develop on leaves, which often turn yellow and drop early

• It affects the growth of the plant as photosynthesis is reduced

Symptoms

• Purple or black spots on the leaves. The leaves can then turn yellow and drop off.

• The loss of leaves means that there are less chloroplasts for photosynthesis.

• The reduction in photosynthesis means the plant has less energy to make flowers

How is it spread?

• Spores from the fungus are carried in the wind or water

Treatment & prevention

• The plant can be treated with fungicide chemicals (the suffix -cide means to kill, so a fungicide kills fungi)

• The leaves can be removed and burned to prevent the spread of the infection over the plant

• Breeding of varieties of plants that have resistance to the disease