title: The Tyrosine Aminomutase TAM1 Is Required for β-Tyrosine Biosynthesis in Rice.
abstract: Non-protein amino acids, often isomers of the standard 20 protein amino acids, have defense-related functions in many plant species. A targeted search for jasmonate-induced metabolites in cultivated rice (Oryza sativa) identified (R)-β-tyrosine, an isomer of the common amino acid (S)-α-tyrosine in the seeds, leaves, roots, and root exudates of the Nipponbare cultivar. Assays with 119 diverse cultivars showed a distinct presence/absence polymorphism, with β-tyrosine being most prevalent in temperate japonica cultivars. Genetic mapping identified a candidate gene on chromosome 12, which was confirmed to encode a tyrosine aminomutase (TAM1) by transient expression in Nicotiana benthamiana and in vitro enzyme assays. A point mutation in TAM1 eliminated β-tyrosine production in Nipponbare. Rice cultivars that do not produce β-tyrosine have a chromosome 12 deletion that encompasses TAM1. Although β-tyrosine accumulation was induced by the plant defense signaling molecule jasmonic acid, bioassays with hemipteran and lepidopteran herbivores showed no negative effects at physiologically relevant β-tyrosine concentrations. In contrast, root growth of Arabidopsis thaliana and other tested dicot plants was inhibited by concentrations as low as 1 μM. As β-tyrosine is exuded into hydroponic medium at higher concentrations, it may contribute to the allelopathic potential of rice.
authors.affiliation: Boyce Thompson Institute for Plant Research, Ithaca, New York 14853.
authors.forename: Jian
authors.identifier: http://orcid.org/0000-0001-8597-9841
authors.initials: J
authors.lastname: Yan
authors.affiliation: Graduate School of Agriculture, Kyoto University, Kyoto 808-8502, Japan.
authors.forename: Takako
authors.initials: T
authors.lastname: Aboshi
authors.affiliation: Graduate School of Agriculture, Kyoto University, Kyoto 808-8502, Japan.
authors.forename: Masayoshi
authors.initials: M
authors.lastname: Teraishi
authors.affiliation: Boyce Thompson Institute for Plant Research, Ithaca, New York 14853.
authors.forename: Susan R
authors.identifier: http://orcid.org/0000-0002-0121-0048
authors.initials: SR
authors.lastname: Strickler
authors.affiliation: Section of Plant Breeding and Genetics, School of Integrated Plant Sciences, Cornell University, Ithaca, New York 14853.
authors.forename: Jennifer E
authors.initials: JE
authors.lastname: Spindel
authors.affiliation: Section of Plant Breeding and Genetics, School of Integrated Plant Sciences, Cornell University, Ithaca, New York 14853.
authors.forename: Chih-Wei
authors.initials: CW
authors.lastname: Tung
authors.affiliation: Graduate School of Agriculture, Kyoto University, Kyoto 808-8502, Japan.
authors.forename: Ryo
authors.initials: R
authors.lastname: Takata
authors.affiliation: Graduate School of Agriculture, Kyoto University, Kyoto 808-8502, Japan.
authors.forename: Fuka
authors.initials: F
authors.lastname: Matsumoto
authors.affiliation: Graduate School of Agriculture, Kyoto University, Kyoto 808-8502, Japan.
authors.forename: Yoshihiro
authors.initials: Y
authors.lastname: Maesaka
authors.affiliation: Section of Plant Breeding and Genetics, School of Integrated Plant Sciences, Cornell University, Ithaca, New York 14853.
authors.forename: Susan R
authors.initials: SR
authors.lastname: McCouch
authors.affiliation: Graduate School of Agriculture, Kyoto University, Kyoto 808-8502, Japan.
authors.forename: Yutaka
authors.initials: Y
authors.lastname: Okumoto
authors.affiliation: Graduate School of Agriculture, Kyoto University, Kyoto 808-8502, Japan.
authors.forename: Naoki
authors.initials: N
authors.lastname: Mori
authors.affiliation: Boyce Thompson Institute for Plant Research, Ithaca, New York 14853 gj32@cornell.edu.
authors.forename: Georg
authors.identifier: http://orcid.org/0000-0002-9675-934X
authors.initials: G
authors.lastname: Jander
mesh_terms: D018506:Gene Expression Regulation, Plant; D012275:Oryza / Q000201:enzymology* / Q000378:metabolism*; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism*; D014443:Tyrosine / Q000096:biosynthesis*
chemical_list: D010940:Plant Proteins; D014443:Tyrosine