The Tyrosine Aminomutase TAM1 Is Required for β-Tyrosine Biosynthesis in Rice
The Tyrosine Aminomutase TAM1 Is Required for β-Tyrosine Biosynthesis in Rice
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DOI：
10.1105/tpc.15.00058
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发表时间：
2015-04
期刊：
影响因子：
11.6
通讯作者：
Jian Yan;Takako Aboshi;M. Teraishi;S. Strickler;J. Spindel;Chih-Wei Tung;Ryo Takata;Fuka Matsumoto;Yoshihiro Maesaka;S. McCouch;Y. Okumoto;N. Mori;G. Jander
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文献类型：
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作者：
Jian Yan;Takako Aboshi;M. Teraishi;S. Strickler;J. Spindel;Chih-Wei Tung;Ryo Takata;Fuka Matsumoto;Yoshihiro Maesaka;S. McCouch;Y. Okumoto;N. Mori;G. Jander
对水稻中茉莉酸诱导的代谢物进行有针对性的研究，发现了常见氨基酸 (S)-α-酪氨酸、(R)-β-酪氨酸的异构体，这可能有助于水稻的化感作用。非蛋白质氨基酸（通常是标准 20 种蛋白质氨基酸的异构体）在许多植物物种中具有防御相关功能。对栽培稻 (Oryza sativa) 中茉莉酸诱导的代谢物进行有针对性的研究，鉴定出 (R)-β-酪氨酸，它是日本晴品种种子、叶、根和根分泌物中常见氨基酸 (S)-α-酪氨酸的异构体。对 119 个不同品种的检测显示出明显的存在/不存在多态性，其中 β-酪氨酸在温带粳稻品种中最为普遍。遗传图谱鉴定了 12 号染色体上的一个候选基因，通过在本塞姆氏烟草中的瞬时表达和体外酶测定，证实该基因编码酪氨酸氨基变位酶 (TAM1)。 TAM1 的点突变消除了日本晴中 β-酪氨酸的产生。不产生 β-酪氨酸的水稻品种存在包含 TAM1 的 12 号染色体缺失。尽管β-酪氨酸积累是由植物防御信号分子茉莉酸诱导的，但对半翅目和鳞翅目食草动物的生物测定显示，在生理相关的β-酪氨酸浓度下没有负面影响。相比之下，低至 1 μM 的浓度会抑制拟南芥和其他测试的双子叶植物的根生长。由于β-酪氨酸以较高浓度渗出到水培培养基中，因此可能有助于水稻的化感作用。
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. 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.