Classes of R proteins

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How do we know this?

LRR region plays a major role in recognitional specificity but it’s often more complicated than that

Conserved Features of Resistance genes (R-genes)

Other common features of R genes

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Model of R-gene action

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How many R-genes are there in the genome?

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Other types of resistance genes

Bs3; A new type of R-gene

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Hm1 and Pto

Is Hm1 a gene-for-gene R gene ?

What’s the difference

The complicated role of Programed cell death

Definitions

Exploitation of R-gene action by necrotrophs

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“Reverse Gene-for-Gene”

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Another example

Victorin induces programmed cell death.

Looked for C. victoriae/Victorin susceptibility in Arabidopsis

Likely lots of other situations where this paradigm pertains

Disease resistance is complicated

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Signalling in Necrotrophic vs, Biotrophic interactions

Ecological consequences

Also…

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Evolution of R-gene Specificity

Some R-genes show conservative selection

How do R-genes products “recognize” the presence of Avr/Effector gene products?

Evidence for Direct interaction

Evidence against direct interaction

The Guard Hypothesis: R proteins function as sensors to “guard” the targets of pathogen effector molecules.

Evidence for the guard hypothesis

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