title: Inhibition of shoot branching by new terpenoid plant hormones.
abstract: Shoot branching is a major determinant of plant architecture and is highly regulated by endogenous and environmental cues. Two classes of hormones, auxin and cytokinin, have long been known to have an important involvement in controlling shoot branching. Previous studies using a series of mutants with enhanced shoot branching suggested the existence of a third class of hormone(s) that is derived from carotenoids, but its chemical identity has been unknown. Here we show that levels of strigolactones, a group of terpenoid lactones, are significantly reduced in some of the branching mutants. Furthermore, application of strigolactones inhibits shoot branching in these mutants. Strigolactones were previously found in root exudates acting as communication chemicals with parasitic weeds and symbiotic arbuscular mycorrhizal fungi. Thus, we propose that strigolactones act as a new hormone class-or their biosynthetic precursors-in regulating above-ground plant architecture, and also have a function in underground communication with other neighbouring organisms.
authors.affiliation: RIKEN Plant Science Center, Tsurumi, Yokohama 230-0045, Japan.
authors.forename: Mikihisa
authors.initials: M
authors.lastname: Umehara
authors.forename: Atsushi
authors.initials: A
authors.lastname: Hanada
authors.forename: Satoko
authors.initials: S
authors.lastname: Yoshida
authors.forename: Kohki
authors.initials: K
authors.lastname: Akiyama
authors.forename: Tomotsugu
authors.initials: T
authors.lastname: Arite
authors.forename: Noriko
authors.initials: N
authors.lastname: Takeda-Kamiya
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Magome
authors.forename: Yuji
authors.initials: Y
authors.lastname: Kamiya
authors.forename: Ken
authors.initials: K
authors.lastname: Shirasu
authors.forename: Koichi
authors.initials: K
authors.lastname: Yoneyama
authors.forename: Junko
authors.initials: J
authors.lastname: Kyozuka
authors.forename: Shinjiro
authors.initials: S
authors.lastname: Yamaguchi
mesh_terms: D017360:Arabidopsis / Q000187:drug effects / Q000235:genetics / Q000254:growth & development; D018506:Gene Expression Regulation, Plant; D007783:Lactones / Q000032:analysis / Q000737:chemistry / Q000378:metabolism / Q000494:pharmacology*; D009154:Mutation; D012275:Oryza / Q000187:drug effects / Q000254:growth & development / Q000378:metabolism / Q000469:parasitology; D010937:Plant Growth Regulators / Q000032:analysis / Q000737:chemistry / Q000378:metabolism / Q000494:pharmacology*; D018517:Plant Roots / Q000469:parasitology; D018520:Plant Shoots / Q000187:drug effects* / Q000254:growth & development*; D036226:Seedlings; D013729:Terpenes / Q000032:analysis / Q000737:chemistry / Q000378:metabolism / Q000494:pharmacology*
chemical_list: C507382:GR24 compound; D007783:Lactones; D010937:Plant Growth Regulators; D013729:Terpenes