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10 Cards in this Set
- Front
- Back
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What is a very common cellular structure of many plant pathogenic bacteria? |
Flagella |
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How are flagella important for plant immunity? |
Flg22 is a highly conserved flagellin fragment which serves as an important PAMP in plant and animal cells. |
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What are the critical receptors for detection of: 1. Bacteria 2. Fungus ? |
Pattern recognition receptors for : 1. Detection of the PAMP: Flg22 by the FLS2 receptor 2. Detection of the PAMP: Chitin by the CEBiP receptor |
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How can PAMP detection in plants be exploited? Give an example. |
Can transfer Pattern recognition receptors from one plant to another to promote a PAMP triggered immune response. E.g EFR gene in A.thaliana -> tomato = bacterial PAMP - 'elf18' triggered response. |
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What methods do gram negative bacteria use to infect plants? |
1. Secrete, via active transport, effector proteins / enzymes into extracellular space / surface of bacterial cell 2. Export proteins into the cell via a type III secretion system. |
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What 4 major genera of plant pathogenic bacteria have conserved TTSS? What is the TTSS evolved from? |
1. Erwinia 2. Pseudomonas 3. Ralstonia 4. Xanthamonas Evolved from flagella |
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How can we investigate bacterial effector genes for virulence? |
1. Bacteria of interest must cause a defence response AND have an effector gene 2. Digest chromosomal DNA 3. Transfer bacterial DNA fragments containing the effector genes into different pathogenic bacteria. 4. Infect different plants with different bacteria. 4. Most do not have uptake the effector gene so cause full disease. Some do not cause disease however and rather incite a PAMP triggered immune response 5. These bacteria which DO NOT cause an immune response have taken up the effector gene. 6. This gene can subsequently be investigated and confirmed to be a PTI response trigger |
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What is AvrBs3? |
A protein which is delivered by a TTSS which localises to the nucleus to activates the gene importin which catalyses the uptake of AvrBs3 like proteins into the nucleus. |
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How can we investigate effectors? |
1. Can be predicted from genome sequences 2. Tertiary structure may provide clues - may resemble a well characterised cellular protein |
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What did investigation of Pseudomonas syringae's TTSS reveal? |
Revealed many TTSS effectors target kinase based recognition processes as well as antimicrobial vesicle trafficking. A very high amount of allelic variation showed that there were rapidly evolving molecular dialogues between effectors and the plant immune systems |
