plant defences Flashcards
Plants have their own immune responses that can limit the invasion and growth of pathogens. One of these responses is called basal resistance. What is basal resistance?
Basal resistance reacts to the presence of a microbe or pathogen-associated molecular pattern (MAMPs or PAMPs), such as flagellins and chitin, found in pathogens.
MAMPS receptors recognise the molecular patterns and begin to cascade a response.
This causes the plant to upregulate the expression of the genes producing chemicals, resulting in an oxidative burst.
What is an oxidative burst?
An oxidative burst is a release of chemicals, such as oxygen species, nitric oxides, hydrogen peroxide and salicylic acid.
The oxidative burst functions to strengthen cell wall linkages and signal to other cells the presence of pathogen threat.
What is CALLOSE?
Callose is a molecule formed in plants
During basal resistance response, callose is deposited between the plant cell membrane and cell wall, around were the pathogen infects.
Callose helps strengthen the cell wall and make it difficult for pathogens to enter adjacent cells.
What happens to the stomata during the basal response?
Stomata are small openings in the epidermis of the plant leaves
During the basal resistance response, the stomata close to prevent the entry of pathogens.
Plants have their own immune response that can limit the invasion and growth of pathogens. One of these responses is called hypersensitive responses.
The hypersensitive responses (HR) can be triggered by the presence of bacteria, viruses, fungi or nematodes.
The response causes localised ‘cell suicide’ (apoptosis) at the site of infection, which cuts off the nutrients and water supply to the pathogens.
What is systematic acquired resistance?
Triggering the HR response can result in a systematic acquired resistance (SAR) to broad ranges of pathogens fora length of time
SAR can be artificially stimulated by spraying plants with ‘plant activators’
Plants have their immune response use that can limit the invasion and growth of pathogens. One of these responses is called RNA Silencing.
RNA silencing is a response to limit the viral spread, by producing enzymes that digest any foreign RNA replicating in their cells.
If the plant is successful that plants will be able to:
recover from infection
recognise the virus RNA in future invasions
