Genes Encoding Recognition of the Effector Protein Ecp5 Are Encoded at Several Loci in the Tomato Genome.

The molecular interactions between tomato and have been an important model for molecular plant pathology. Complex genetic loci on tomato chromosomes 1 and 6 harbor genes for resistance to , encoding receptor like-proteins that perceive distinct effectors and trigger plant defenses. Here, we report classical mapping strategies for loci in tomato accessions that respond to effector Ecp5, which is very sequence-monomorphic. We screened 139 wild tomato accessions for an Ecp5-induced hypersensitive response, and in five accessions, the Ecp5-induced hypersensitive response segregated as a monogenic trait, mapping to distinct loci in the tomato genome. We identified at least three loci on chromosomes 1, 7 and 12 that harbor distinct genes in four different accessions. Our mapping showed that the in G1.1161 is located at the locus. The in LA0722 was mapped to the bottom arm of chromosome 7, while the genes in Ontario 7522 and LA2852 were mapped to the same locus on the top arm of chromosome 12. Bi-parental crosses between accessions carrying distinct Cf-Ecp5 genes revealed putative genetically unlinked suppressors of the Ecp5-induced hypersensitive response. Our mapping also showed that is located on chromosome 11, close to the locus. The Ecp5-induced hypersensitive response is widely distributed within tomato species and is variable in strength. This novel example of convergent evolution could be used for choosing different functional genes according to individual plant breeding needs.