Allelic Genes Activate Rice Blight Resistance Suppressed by Interfering TAL Effectors.

pathovar () uses transcription activator-like effectors (TALEs) to cause bacterial blight (BB) in rice. In turn, rice has evolved several mechanisms to resist BB by targeting TALEs. One mechanism involves the nucleotide-binding leucine-rich repeat (NLR) resistance gene and TALEs. Reciprocally, has evolved TALE variants, C-terminally truncated versions (interfering TALEs or iTALEs), to overcome resistance. However, it remains unknown to what extent the two co-adaptive mechanisms mediate -rice interactions. In this study, we cloned and characterized five additional allelic genes, , , , , and from a collection of rice accessions. Sequence analysis revealed that and from different rice cultivars are identical. These genes and their predicted proteins were found to be highly conserved, forming a group of alleles. The XA1 alleles could be distinguished by the number of C-terminal tandem repeats consisting of 93 amino acid residues and ranged from four in XA14 to seven in XA45(t). allelic genes were identified in the 3000 rice genomes surveyed. On the other hand, iTALEs could suppress the resistance mediated by allelic genes, and iTALE genes were prevalent (∼95%) in Asian, but not in African strains. Our findings demonstrate the prominence of a defense mechanism in which rice depends on alleles and a counteracting mechanism in which relies on iTALEs for BB.