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

Another example- Rin 4

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So Rin4 is guarded by at least two R-genes in Arabidopsis; RPM1(mediates AvrB recognition) and RPS2 (mediated AvrRpt2 recognition)

Maybe

Another Example:Pto/AvrPto

Why in this case is Pto rather than Prf identified as the resistance gene?

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Aside:Hybrid Necrosis

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Bomblies et al (2007) Plos Biology 5:e236

Why might Hybrid Necrosis Occur?

How does an understanding of the guard hypothesis change the way we view host-pathogen dynamics

So what about evolution?

A further elaboration

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This is an unstable situation

Evidence

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BS3

What happens next?

Most plants are resistant to most pathogens

Non-Host Resistance is likely based on a number of mechanisms

The plant basal defence system

MAMPS are recognized by receptors at the cell surface