Genetic complexity of pathogen perception by plants: the example of Rcr3, a tomato gene required specifically by Cf-2.
Genetic analysis of plant-pathogen interactions has demonstrated that resistance to infection is often determined by the interaction of dominant plant resistance (R) genes and dominant pathogen-encoded avirulence (Avr) genes. It was postulated that R genes encode receptors for Avr determinants. A large number of R genes and their cognate Avr genes have now been analyzed at the molecular level. R gene loci are extremely polymorphic, particularly in sequences encoding amino acids of the leucine-rich repeat motif. A major challenge is to determine how Avr perception by R proteins triggers the plant defense response. Mutational analysis has identified several genes required for the function of specific R proteins. Here we report the identification of Rcr3, a tomato gene required specifically for Cf-2-mediated resistance. We propose that Avr products interact with host proteins to promote disease, and that R proteins "guard" these host components and initiate Avr-dependent plant defense responses.
The Sainsbury Laboratory, John Innes Centre, Norwich Research Park, Colney Lane, Norwich NR4 7UH, United Kingdom.
M S
MS
Dixon
C
C
Golstein
C M
CM
Thomas
E A
EA
van Der Biezen
J D
JD
Jones
D005075:Biological Evolution; D002874:Chromosome Mapping; D017343:Genes, Plant; D018551:Solanum lycopersicum / Q000235:genetics* / Q000382:microbiology*