R gene evolution and structure

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R gene evolution and structure

• Major classes of R genes
• R gene evolution
• Down stream signaling

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Cloned disease resistance genes
NBS-LRR is largest class Major subclasses of
NBS-LRR are - CC-NBS-LRR -
TIR-NBS-LRR R gene class and pathogen are
not correlated TIR-NBS-LRR are not found
in monocots
Liu et al. 2007. J. Genet. Genom. 34765-776
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(No Transcript)
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Major classes of R proteins
Liu et al. 2007. J. Genet. Genom. 34765-776
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Tammeling et al. (2002) Plant Cell 14, 29292939
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Example of leucine rich repeat region
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Variation in numbers of LRRs
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NB-LRR proteins are involved in animal innate
immunity
Inohara. 2003. Nat. Rev. Immunol. 3371382
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NB-LRR proteins are involved in animal innate
immunity
Ting et al. 2008. Nat. Rev. Immunol. 8372-379
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Signaling by animal NLR proteins
Ting et al. 2008. Nat. Rev. Immunol. 8372-379
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The zigzag model for plant pathogen interactions
Dangl and Jones. 2006. Nature 444323-329
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A modification of the zigzag model - Repair
Lee et al. 2008. Mol. Cell. Proteomics. In press
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Structure Cf resistance loci in tomato
Wulff et al. (2004) Genetics 167459-70
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Phylogeny and genomic organization of (NBS-LRR)
genes in Arabidopsis thaliana.
Leister. (2004) TIGS 20116-122
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Leister. (2004) TIGS 20116-122
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Molecular evolution of R genes at complex loci -
continued
Ways that plants could and do evolve novel
resistance specificities
Hammond-kosack (1997) Ann. Rev. Plant Phys.
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Mechanisms that contribute to R gene diversity
Leister. (2004) TIGS 20116-122
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Slow and fast evolving R genes
R gene evolution is not homogeneous
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Evidence that R genes evolve at different rates
Kuang et al. (2004) Plant Cell 162870
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LRR is least conserved part of R genes
Michelmore and Meyers. 1998. Genome Res. 8
1113-1130
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Birth and death model for R gene evolution
DIRECT OR INDIRECT PATHOGEN PRODUCTS
SIGNAL CASCADE, RESISTANCE RESPONSE
RAPID CELL DEATH
RECOGNITION
SELECTION ON PATHOGEN POPULATION FOR LACK OF OF
AVIRULENCE FACTOR
NO
RECOGNITION
COMPATIBLE INTERACTION
SELECTION ON PLANT POPULATION FOR NEW RESISTANCE
SPECIFICITY
SIGNAL CASCADE, RESISTANCE RESPONSE
RAPID CELL DEATH
RECOGNITION
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Dangl and Jones. 2006. Nature 444323-329
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van der Hoorn Kamoun 2008. Plant Cell 20
20092017
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van der Hoorn Kamoun 2008. Plant Cell 20
20092017
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Genetic tests to discriminate between the guard
and decoy models
van der Hoorn Kamoun 2008. Plant Cell 20
20092017
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Martin et al. 2003 ARPB
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Role of EDS1 and PAD4 in plant defense
Wiermer et al. 2005. Curr. Opin. Plant Biol.
8383389
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RAR1 and SGT1
RAR1 SGT1 interact with each other RAR1 SGT1
interact with HSP90 HSP90 associates with R
proteins SGT1 is a component of the SCF type E3
ubiquitin ligase complex (SKP/CULLEN/F-BOX)
SGT1 interacts with SKP1 SGT1 and RAR1 also
interact with the COP9 signalosome complex also
involved in protein degradation via the
ubiquitin-proteasome pathway
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The nuclear localization of N is required for
defense response



Burch-Smith et al. 2007. PLoS Biology 5e68
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Model for N protein function
RPS4 and Mla resistance proteins have also been
shown to have a requirement for nuclear
localization.
Burch-Smith et al. 2007. PLoS Biology 5e68
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Phylogenetic relationship of (a) TIR-NBS-LRR (b)
CC-NBS-LRR - based on NB domain
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Domain structure of NBS-LRR proteins
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Relationship between I genes and resistance to
races of Fol in tomato
Avr1, Avr2, Avr3
avr1?, Avr2, Avr3
avr1, Avr2, Avr3
Avr1, Avr2, Avr3
avr1, avr2, Avr3
Avr1, avr2, Avr3
Houterman et al. 2008. PLoS Pathogens. 4e1000061
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Evidence for arms race in tomato vs Fusarium
oxysporum fsp lycopersici intxn
Fol lacking Avr3 suffers severe fitness
penalty Hypothesis I-3 and I-2 evolved to
recognize Fol Avr1 evolved to suppress I-3,
because fungus needs Avr3 for full virulence.
Also effective against Avr2. I or I-1 evolved to
recognize Avr1
Houterman et al. 2008. PLoS Pathogens. 4e1000061