Plants innate defence system
First line of defence and involves the cell wall and cuticle preventing water loss and act as a physical barrier to prevent pathogens entering.
Involves antimicrobial chemicals
Naturally occurring enzyme inhibitors
Plants General-induced Immunity
Involves pattern recognition receptors which are able to recognise microbe associated molecule patterns.
Triggered via signalling pathways:
- production of lignin to reinforce cell wall.
- Production and accumulation of proteins into the cell membrane. Inhibit effectors that are secreted by pathogens and stop reproduction and growth of pathogen.
- Production and secretion of antimicrobial molecules
- Production and secretion of signalling hormones
- Activation of genes to produce more antimicrobial enzymes and proteins.
Specific-induced immunity in plants
Involves the hypersensitive response.
Only occurs when the plant identifies and recognises a specific antigen.
Involves resistance proteins recognising the antigen triggering responses via a signalling pathway resulting in the activation of genes responsible for the coding and production of enzymes. Eventually leads to apoptosis.
Apoptosis is the programmed death of infected cells and surrounding of infected cells. The last defence barrier to defend against pathogen.
What is an antigen
An antigen is a protein molecule present on the pathogen
Example of plant response to pathogen
Affected plant: Macadamia
Description of plant: Native Australian tree that produces edible nuts and grows in subtropical climates.
Pathogen name: Phytophthora Cinnamomi (Fungi)
Symptoms of disease: Rooting at the rots, wilting, yellowing of leaves.
Control of disease: Improving soil drainage, use of resistance rootstocks, Phosphite Fungicides.
First line of defence in humans
Skin: Tough outer barrier to prevent entry by microbes. Dry to prevent pathogen growth. Contains a population of harmless bacteria to stop harmful microbes.
Mucus: Pathogens are trapped in mucus stopping from entering the body.
Cilia: Tiny ‘hairs’ that line respiratory surfaces constantly beating to move mucus containing trapped pathogens towards the throat.
