tA Single Amino Acid Difference Distinguishes Resistant and Susceptible Alleles of the Rice Blast Resistance Gene Pi-ta

• Published in: The Plant cell Vol. 12; no. 11; pp. 2033 - 2045
• Main Authors: Bryan, Gregory T., Wu, Kun-Sheng, Farrall, Leonard, Jia, Yulin, Hershey, Howard P., McAdams, Sean A., Faulk, Kristina N., Donaldson, Gail K., Tarchini, Renato, Valent, Barbara
• Format: Journal Article
• Language: English
• Published: United States American Society of Plant Physiologists 01.11.2000; American Society of Plant Biologists
• Subjects: Alleles; Amino Acid Sequence; Amino Acid Substitution; Amino acids; Base Sequence; Blasts; Chromosomes, Artificial, Bacterial; Cloning; Cloning, Molecular; Complementary DNA; DNA; DNA Primers; Genes; Metalloendopeptidases - chemistry; Metalloendopeptidases - genetics; Molecular Sequence Data; Pathogens; Plant cells; Plant Proteins; Proteins; Rice
• ISSN: 1040-4651; 1532-298X
• DOI: 10.2307/3871103

The rice blast resistance (R) gene Pi-ta mediates gene-for-gene resistance against strains of the fungus Magnaporthe grisea that express avirulent alleles of AVR-Pita. Using a map-based cloning strategy, we cloned Pi-ta, which is linked to the centromere of chromosome 12. Pi-ta encodes a predicted 928-amino acid cytoplasmic receptor with a centrally localized nucleotide binding site. A single-copy gene, Pi-ta shows low constitutive expression in both resistant and susceptible rice. Susceptible rice varieties contain $pi\text{-}ta^{-}$ alleles encoding predicted proteins that share a single amino acid difference relative to the Pi-ta resistance protein: serine instead of alanine at position 918. Transient expression in rice cells of a $Pi\text{-}ta^{+}$ R gene together with $AVR\text{-}Pita^{+}$ induces a resistance response. No resistance response is induced in transient assays that use a naturally occurring $pi\text{-}ta^{-}$ allele differing only by the serine at position 918. Rice varieties reported to have the linked $Pi\text{-}ta^{2}$ gene contain Pi-ta plus at least one other R gene, potentially explaining the broadened resistance spectrum of $Pi\text{-}ta^{2}$ relative to Pi-ta. Molecular cloning of the AVR-Pita and Pi-ta genes will aid in deployment of R genes for effective genetic control of rice blast disease.