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M7IQ2- Plant and Animal Response - Coggle Diagram
M7IQ2- Plant and
Animal Response
Plants
Types of Plant Diseases
bacterium
: bacterial wilt of potatoes- galls, wilting, local spots, lesions
virus
: tobacco mosaic virus- yellowing/mottling, deformed leaves, tissue death
fungal
: dutch elm disease- causes conducting tissue of plants to wilt and collapse
parasitic worm:
roundworm- attacks roots and underground stems
chewing insect:
caterpillar- eggs on the underside of leaves, burrowing into fruit, eating seedlings
sap-sucking insect:
aphid- deformed leaves and petals
Case Study
phytophthora cinnamomi
can spread easily, causing disease,
death and potential extinction.
grows in warm, damp soil and
infects the roots of a tree. the
fungus releases water-borne
spores which infect healthy roots,
meaning the infected tree can no long
absorb water and will slowly die of
dehydration.
Plant Responses
Gene for Gene Resistance
this relationship states that a plant must have a resistance gene that matches a pathogen's avirulence gene in order to be immune
General Defences
physical
:
leaf structure: thorns/hairs/bristles to repel insects, drooping leaves deter contact with insects that may carry disease, leaf shape prevents water from pooling.
barrier: waxy cuticle made of lignin and cutin, cell wall prevents pathogens from entering the cell, bark is an external layer of dead cells.
chemical
:
toxins: target insects that feed on plants, reducing the number of insects that may have diseases that are in contact with the plant.
antimicrobial: a chemical that kills microbes
Basal Resistance
plant immediately fortifies itself against infection by becoming impenetrable.
physical
:
callose deposition: a polysaccharide that plants deposit between the cell walls and plasma membranes when stressed.
closed stomata: stomata close upon sensing pathogens.
chemical
:
soponins destroy the pathogen membrane
phytoalexins impair pathogen growth
defensins at upon molecular targets in the pathogens plasma membrane
Hypersensitive/MAMPS
H: limits pathogen access to the host plant by apoptosis (programmed cell death).
restricts the pathogen to the infected site and saves the rest of the plant.
M: detects pathogens by microbe-associated molecular patterns on their surface.
Systemic Acquired Resistance
after exposure to a pathogen, the plant is able to mount a quicker and faster attack after subsequent exposure to the same pathogen
galls = abnormal growths (i.e- plant tumours)
wilting = loss of rigidity of non-woody parts of plants
lesions = areas of tissue damaged through injury or disease
tissue death - death of plant or animal tissue through injury or disease
pustules = small raised spot or rounded swelling (usually from fungal infections)
mottled = pattern of irregular marks, spots, streaks, blotches or patches of different shades or colours
Animals
Physical
Responses
Vomiting/Diarrhoea
happens in response to many different signals, one of which is the presence of pathogens in the gut (gastroenteritis). it is the body's way of expelling harmful substances.
at the other end of the digestive system, diarrhoea expels microorganism quickly from the gastrointestinal system
Fever
an increase in body temperature that occurs as a consequence of inflammatory cytokines altering the body's set temperature.
fever slows the replication of bacteria and viruses by shifting temperature away from their optimal range.
moderate increases in temperature increases the activity and proliferation of leukocytes.
Increased Urination
when the bladder lining is being attacked by a pathogen, it is common to have the need to pass frequent small amounts of urine.
a response designed to flush out pathogens from the body
Wound Healing
priorities are to:
stop any bleeding and maintain normal blood pressure by vasoconstriction and forming a platelet plug.
confront pathogens via inflammatory response.
heal and repair wound to re-establish the barrier. a protein called fibrin forms a mesh to trap more platelets and form a clot to seal the wound.
forming a granuloma: a wall of dead cells that surrounds infected cells.
Chemical
Responses
The Complement System
the complement system is a group of around 20 soluble proteins that assist other defence mechanisms in destroying extracellular proteins.
can stimulate phagocytes to the site of infection or destroy the membranes of the invading pathogen.
can 'punch' holes in microbial cell membranes, causing the cell contents to leak out.
Cytokines
cytokines are small signalling molecules of the immune system that coordinate many aspects of the immune response.
during infection they promote the development and differentiation of T and B lymphocytes.
act as a chemical signal to viruses to stop replicating.
play a role in lethargy, muscle pain and nausea, with the implication that the animal will isolate itself and rest, preventing spreading infection to other animals.
Inflammation
a chemical response that helps
wound repair and leads to pathogen
destruction.
a non-specific defence mechanism
that occurs at the sight of infection.
Info
an
epizootic
is the animal equivalent of a human epidemic. australia reports to the World Organisation for Animal Health if there is a detection of an animal disease, especially one that can be transmitted to humans.
effects include
: death, short-term illness, economic loss due to reduced yield or damage to animals, loss of trading opportunities, low grow rates, loss of female fertility.