Two linked pairs of Arabidopsis TNL resistance genes independently confer recognition of bacterial effector AvrRps4.
Plant immunity requires recognition of pathogen effectors by intracellular NB-LRR immune receptors encoded by Resistance (R) genes. Most R proteins recognize a specific effector, but some function in pairs that recognize multiple effectors. Arabidopsis thaliana TIR-NB-LRR proteins RRS1-R and RPS4 together recognize two bacterial effectors, AvrRps4 from Pseudomonas syringae and PopP2 from Ralstonia solanacearum. However, AvrRps4, but not PopP2, is recognized in rrs1/rps4 mutants. We reveal an R gene pair that resembles and is linked to RRS1/RPS4, designated as RRS1B/RPS4B, which confers recognition of AvrRps4 but not PopP2. Like RRS1/RPS4, RRS1B/RPS4B proteins associate and activate defence genes upon AvrRps4 recognition. Inappropriate combinations (RRS1/RPS4B or RRS1B/RPS4) are non-functional and this specificity is not TIR domain dependent. Distinct putative orthologues of both pairs are maintained in the genomes of Arabidopsis thaliana relatives and are likely derived from a common ancestor pair. Our results provide novel insights into paired R gene function and evolution.
Sainsbury Laboratory, Norwich Research Park, Norwich NR4 7UH, UK.
Simon B
SB
Saucet
Sainsbury Laboratory, Norwich Research Park, Norwich NR4 7UH, UK.
Yan
Y
Ma
Sainsbury Laboratory, Norwich Research Park, Norwich NR4 7UH, UK.
Panagiotis F
PF
Sarris
Sainsbury Laboratory, Norwich Research Park, Norwich NR4 7UH, UK.
Oliver J
OJ
Furzer
Bioprotection Research Centre, Institute of Agriculture and Environment, Massey University, Private Bag 11222, Palmerston North 4442, New Zealand.
Kee Hoon
KH
Sohn
Sainsbury Laboratory, Norwich Research Park, Norwich NR4 7UH, UK.
Jonathan D G
JD
Jones
D017360:Arabidopsis / Q000235:genetics* / Q000276:immunology; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D001426:Bacterial Proteins / Q000378:metabolism*; D002874:Chromosome Mapping; D017931:DNA Primers / Q000235:genetics; D019143:Evolution, Molecular; D015151:Immunoblotting; D000090263:Leucine-Rich Repeat Proteins; D010802:Phylogeny; D057865:Plant Immunity / Q000235:genetics*; D018515:Plant Leaves / Q000235:genetics / Q000378:metabolism; D010940:Plant Proteins / Q000378:metabolism*; D011506:Proteins / Q000235:genetics / Q000378:metabolism; D044224:Pseudomonas syringae / Q000235:genetics / Q000378:metabolism; D043368:Ralstonia solanacearum / Q000235:genetics / Q000378:metabolism; D060888:Real-Time Polymerase Chain Reaction; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013045:Species Specificity; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*
D029681:Arabidopsis Proteins; D001426:Bacterial Proteins; D017931:DNA Primers; D000090263:Leucine-Rich Repeat Proteins; D010940:Plant Proteins; D011506:Proteins; C000604874:RPS4B protein, Arabidopsis; C582898:RRS1 protein, Arabidopsis; C000604873:TTR1 protein, Arabidopsis; D014157:Transcription Factors; C097421:rps4 protein, plant