The Tyrosine Aminomutase TAM1 Is Required for β-Tyrosine Biosynthesis in Rice. Issue 4 (21st April 2015)

• Record Type: Journal Article
• Authors: Yan, Jian; Aboshi, Takako; Teraishi, Masayoshi; Strickler, Susan R.; Spindel, Jennifer E.; Tung, Chih-Wei; Takata, Ryo; Matsumoto, Fuka; Maesaka, Yoshihiro; McCouch, Susan R.; Okumoto, Yutaka; Mori, Naoki; Jander, Georg
• Is Part Of: The Plant Cell. Volume 27:Issue 4(2015)
• Page Start: 1265
• Page End: 1278
• Publication Date: 2015-04-21
• DOI: 10.1105/tpc.15.00058
• Languages: English
• ISSNs: 1040-4651

Abstract

Abstract : A targeted search for jasmonate-induced metabolites in rice identified an isomer of the common amino acid ( S )-α-tyrosine, ( R )-β-tyrosine, which may contribute to the allelopathic potential of 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.