title: The rice FISH BONE gene encodes a tryptophan aminotransferase, which affects pleiotropic auxin-related processes.
abstract: Auxin is a fundamental plant hormone and its localization within organs plays pivotal roles in plant growth and development. Analysis of many Arabidopsis mutants that were defective in auxin biosynthesis revealed that the indole-3-pyruvic acid (IPA) pathway, catalyzed by the TRYPTOPHAN AMINOTRANSFERASE OF ARABIDOPSIS (TAA) and YUCCA (YUC) families, is the major biosynthetic pathway of indole-3-acetic acid (IAA). In contrast, little information is known about the molecular mechanisms of auxin biosynthesis in rice. In this study, we identified a auxin-related rice mutant, fish bone (fib). FIB encodes an orthologue of TAA genes and loss of FIB function resulted in pleiotropic abnormal phenotypes, such as small leaves with large lamina joint angles, abnormal vascular development, small panicles, abnormal organ identity and defects in root development, together with a reduction in internal IAA levels. Moreover, we found that auxin sensitivity and polar transport activity were altered in the fib mutant. From these results, we suggest that FIB plays a pivotal role in IAA biosynthesis in rice and that auxin biosynthesis, transport and sensitivity are closely interrelated.
authors.affiliation: Graduate School of Agricultural and Life Sciences, University of Tokyo, Tokyo, 113-8657, Japan.
authors.forename: Takanori
authors.initials: T
authors.lastname: Yoshikawa
authors.forename: Momoyo
authors.initials: M
authors.lastname: Ito
authors.forename: Tsuyoshi
authors.initials: T
authors.lastname: Sumikura
authors.forename: Akira
authors.initials: A
authors.lastname: Nakayama
authors.forename: Takeshi
authors.initials: T
authors.lastname: Nishimura
authors.forename: Hidemi
authors.initials: H
authors.lastname: Kitano
authors.forename: Isomaro
authors.initials: I
authors.lastname: Yamaguchi
authors.forename: Tomokazu
authors.initials: T
authors.lastname: Koshiba
authors.forename: Ken-Ichiro
authors.initials: K
authors.lastname: Hibara
authors.forename: Yasuo
authors.initials: Y
authors.lastname: Nagato
authors.forename: Jun-Ichi
authors.initials: J
authors.lastname: Itoh
mesh_terms: D000595:Amino Acid Sequence; D001692:Biological Transport / Q000235:genetics; D003001:Cloning, Molecular; D007210:Indoleacetic Acids / Q000378:metabolism*; D008969:Molecular Sequence Data; D012275:Oryza / Q000201:enzymology / Q000235:genetics* / Q000378:metabolism; D010641:Phenotype; D010937:Plant Growth Regulators / Q000378:metabolism*; D010940:Plant Proteins / Q000737:chemistry / Q000235:genetics / Q000502:physiology*; D016415:Sequence Alignment; D020539:Sequence Analysis, Protein; D051279:Tryptophan Transaminase / Q000737:chemistry / Q000235:genetics / Q000502:physiology*
chemical_list: D007210:Indoleacetic Acids; D010937:Plant Growth Regulators; D010940:Plant Proteins; C030737:indoleacetic acid; D051279:Tryptophan Transaminase
keywords: FISH BONE; Oryza sativa L.; auxin sensitivity; indole-3-acetic acid; polar auxin transport; rice; tryptophan aminotransferase