Protection of plants Flashcards
what is 30% of agricultural yield lost to
pests - insects
disease - pathogens
what are BCAs
Biological Control Agents
what are the 3 ways BCAs work
repress pathogen directly
occupy niches to prevent pathogen colonising plants
induce plant defence responses - host mediated
why are fungi good BCAs, especially mycoparatites
they can be parasitic on another fungus
can produce hydrolytic enzymes to degrade other fungi
can be soil born - occupy niche around plant roots - protects plants against soil born fungal pathogens
what is, does the species Argobacterium cause
a soil bacterium, causes crown gall disease
what is Muscador albus and what can it do
smelly white fungus, an endophyte
produces many volatiles that can kill other fungi, but individually harmless to plants and animals
what is root and butt rot of conifers, and what is the cause
fungus, spreads through roots to live trees, enters through fresh stumps
what can be used to treat root rot
urea to treat stumps
sodium nitrate to hazardous
what microorganism is used to treat root rot
P. gigantea - doesn’t kill living trees - when applied to stumps it prevents surrounding trees getting infected by competing for resources on stump surface
what is chestnut blight and what causes it
fungus that invades bark
what is Bt and what is its function
Bt - Bacillus thuringiensis - an insecticidal bacterium
a mixture of dried spores and toxin crystals - both dusted onto leaves - no threat to humans but kills insects
how does Bt kill insects
the ph causes ion leakage in insects stomach, allowing the bacterial spores to germinate - bacteria invade and kill host
what has been done on Bt to further enhance agriculture
transgenic GM crops created to express the toxin crystal genes
many different strains of the bacterium created which produce different toxins effective against different insect species
B. substilis spores
incorporated into biocontrol products which are effective against wide range of fungal pathogens
what gene is engineered into tobacco and potato and why
the gene that produces the AiiA gene
inactivates quorum sensing in plant pathogen E.carotovora to give high level of resistance
what are Pseudomonas and what do they do
gram -ive bacteria
incorporated into products such as ‘dagger’ for control of damping off diseases
what are damping off diseases and what are they caused by
kill/weaken seedlings in wet/ cool conditions - caused by oomycetes
what are oomycetes
eukaryotes - fungus-like filamentous microos
what do bacteria produce that inhibit plant pathogens
antimicrobials - phenazine, oomycin
How do pseudomonas help prevent frost damage
act as intercellular ice nucleators
what plant disease does Agribacterium tumefaciens cause
crown gall disease
what is agrocin K1026 and what does it do
produced by some strains of Agrobacterium radiobacter
new GM strain of Agrocin that kills A. tumefaciens
used as a biocontrol
