Andy Bailey Flashcards
what is a desease
Any disturbance brought about by a pathogen (organism which causes disease) or an environmental factor which interferes with manufacture, translocation, or utilisation of food, mineral nutrients, and water in such a way that the affected plant changes in appearance and/or yields less than a normal, healthy plant of the same variety
Pathogen
an organism capable of causing disease
Virulence
the degree of disease caused on a particular host
pathovar (pv.)
in bacteria, a sub-species/group of strains that infect a certain host
forma specialis (f.sp.)
in fungi, a group of races that infect certain plants within a genus or species
Koch’s Postulate
- The pathogen must always be present in the plants showing the disease
- It must be isolated and grown in pure culture (or in test plants) and described
- On reintroduction into susceptible plants the same symptoms should be reproduced
- On re-isolation it is identical to that observed in 2.
tabtoxin
in pseudomonas syringe pv. tabaci. causing chlorotic halos around the lesion beyond the spread of the bacteria
Amilovoran
in erwinia amylovora. extracellular polysaccaride, attracts insects (vectors)
Puccinia graminis
Cereal rust. Very complex lifecycle: 5 spors, 2 hosts. Example for complexity of pathogens. And different mechanisms used to attack. I.e the 2 hosts in order to survivem
Avenucinase
Example for detoxification of host products. Stops the antifungal saponin from making pores in the fungal PM
Pathogenesis Related Proteins (PR)
New proteins in response to infection
5fam in tobacco: Antifungal peptides (alkaloid), glutanases, chitinases, antifungal peptides (acidic), protease inhibitors
PAMP
Pathogen associated molecular patterns
Detecting pathogens
NBS-LRR
Nucleotide Binding site - leucine rich receptor - the receptors
Oxidative burst
Transient Rapid Production of H2O2 Superoxide anion Oxidise membrane lipids Trigger HR Lipoxygenase - cell communication
Hypersensitive Response (HR)
Apoptosis (PCD)