title: Forward genetic screen for auxin-deficient mutants by cytokinin.
abstract: Identification of mutants with impairments in auxin biosynthesis and dynamics by forward genetic screening is hindered by the complexity, redundancy and necessity of the pathways involved. Furthermore, although a few auxin-deficient mutants have been recently identified by screening for altered responses to shade, ethylene, N-1-naphthylphthalamic acid (NPA) or cytokinin (CK), there is still a lack of robust markers for systematically isolating such mutants. We hypothesized that a potentially suitable phenotypic marker is root curling induced by CK, as observed in the auxin biosynthesis mutant CK-induced root curling 1 / tryptophan aminotransferase of Arabidopsis 1 (ckrc1/taa1). Phenotypic observations, genetic analyses and biochemical complementation tests of Arabidopsis seedlings displaying the trait in large-scale genetic screens showed that it can facilitate isolation of mutants with perturbations in auxin biosynthesis, transport and signaling. However, unlike transport/signaling mutants, the curled (or wavy) root phenotypes of auxin-deficient mutants were significantly induced by CKs and could be rescued by exogenous auxins. Mutants allelic to several known auxin biosynthesis mutants were re-isolated, but several new classes of auxin-deficient mutants were also isolated. The findings show that CK-induced root curling provides an effective marker for discovering genes involved in auxin biosynthesis or homeostasis.
authors.affiliation: Institute of Cell Biology and MOE Key Laboratory of Cell Activities and Stress Adaptations, Lanzhou University, Lanzhou 730000, China.
authors.forename: Lei
authors.initials: L
authors.lastname: Wu
authors.affiliation: Institute of Cell Biology and MOE Key Laboratory of Cell Activities and Stress Adaptations, Lanzhou University, Lanzhou 730000, China.
authors.forename: Pan
authors.initials: P
authors.lastname: Luo
authors.affiliation: Institute of Cell Biology and MOE Key Laboratory of Cell Activities and Stress Adaptations, Lanzhou University, Lanzhou 730000, China.
authors.forename: Dong-Wei
authors.initials: DW
authors.lastname: Di
authors.affiliation: Institute of Cell Biology and MOE Key Laboratory of Cell Activities and Stress Adaptations, Lanzhou University, Lanzhou 730000, China.
authors.forename: Li
authors.initials: L
authors.lastname: Wang
authors.affiliation: Institute of Cell Biology and MOE Key Laboratory of Cell Activities and Stress Adaptations, Lanzhou University, Lanzhou 730000, China.
authors.forename: Ming
authors.initials: M
authors.lastname: Wang
authors.affiliation: Institute of Cell Biology and MOE Key Laboratory of Cell Activities and Stress Adaptations, Lanzhou University, Lanzhou 730000, China.
authors.forename: Cheng-Kai
authors.initials: CK
authors.lastname: Lu
authors.affiliation: Institute of Cell Biology and MOE Key Laboratory of Cell Activities and Stress Adaptations, Lanzhou University, Lanzhou 730000, China.
authors.forename: Shao-Dong
authors.initials: SD
authors.lastname: Wei
authors.affiliation: Institute of Cell Biology and MOE Key Laboratory of Cell Activities and Stress Adaptations, Lanzhou University, Lanzhou 730000, China.
authors.forename: Li
authors.initials: L
authors.lastname: Zhang
authors.affiliation: Institute of Cell Biology and MOE Key Laboratory of Cell Activities and Stress Adaptations, Lanzhou University, Lanzhou 730000, China.
authors.forename: Tian-Zi
authors.initials: TZ
authors.lastname: Zhang
authors.affiliation: Laboratory of Growth Regulators, Centre of the Region Haná for Biotechnological and Agricultural Research, Institute of Experimental Botany ASCR and Palacký University, Šlechtitelů 11, Olomouc CZ-783 71, Czech Republic.
authors.forename: Petra
authors.initials: P
authors.lastname: Amakorová
authors.affiliation: Laboratory of Growth Regulators, Centre of the Region Haná for Biotechnological and Agricultural Research, Institute of Experimental Botany ASCR and Palacký University, Šlechtitelů 11, Olomouc CZ-783 71, Czech Republic.
authors.forename: Miroslav
authors.initials: M
authors.lastname: Strnad
authors.affiliation: Laboratory of Growth Regulators, Centre of the Region Haná for Biotechnological and Agricultural Research, Institute of Experimental Botany ASCR and Palacký University, Šlechtitelů 11, Olomouc CZ-783 71, Czech Republic.
authors.forename: Ondřej
authors.initials: O
authors.lastname: Novák
authors.affiliation: Institute of Cell Biology and MOE Key Laboratory of Cell Activities and Stress Adaptations, Lanzhou University, Lanzhou 730000, China.
authors.forename: Guang-Qin
authors.initials: GQ
authors.lastname: Guo
mesh_terms: D017360:Arabidopsis / Q000201:enzymology / Q000235:genetics; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism; D001692:Biological Transport / Q000187:drug effects; D003583:Cytokinins / Q000378:metabolism*; D007210:Indoleacetic Acids / Q000378:metabolism* / Q000494:pharmacology; D009154:Mutation; D010641:Phenotype; D010937:Plant Growth Regulators / Q000096:biosynthesis*; D018517:Plant Roots / Q000201:enzymology / Q000235:genetics / Q000254:growth & development; D036226:Seedlings / Q000187:drug effects / Q000254:growth & development / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects; D051279:Tryptophan Transaminase / Q000235:genetics / Q000378:metabolism
chemical_list: D029681:Arabidopsis Proteins; D003583:Cytokinins; D007210:Indoleacetic Acids; D010937:Plant Growth Regulators; C030737:indoleacetic acid; D051279:Tryptophan Transaminase