title: Two-Step Regulation of a Meristematic Cell Population Acting in Shoot Branching in Arabidopsis.
abstract: Shoot branching requires the establishment of new meristems harboring stem cells; this phenomenon raises questions about the precise regulation of meristematic fate. In seed plants, these new meristems initiate in leaf axils to enable lateral shoot branching. Using live-cell imaging of leaf axil cells, we show that the initiation of axillary meristems requires a meristematic cell population continuously expressing the meristem marker SHOOT MERISTEMLESS (STM). The maintenance of STM expression depends on the leaf axil auxin minimum. Ectopic expression of STM is insufficient to activate axillary buds formation from plants that have lost leaf axil STM expressing cells. This suggests that some cells undergo irreversible commitment to a developmental fate. In more mature leaves, REVOLUTA (REV) directly up-regulates STM expression in leaf axil meristematic cells, but not in differentiated cells, to establish axillary meristems. Cell type-specific binding of REV to the STM region correlates with epigenetic modifications. Our data favor a threshold model for axillary meristem initiation, in which low levels of STM maintain meristematic competence and high levels of STM lead to meristem initiation.
authors.affiliation: State Key Laboratory of Plant Genomics, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, and National Center for Plant Gene Research, Beijing, China.|University of Chinese Academy of Sciences, Beijing, China.
authors.forename: Bihai
authors.initials: B
authors.lastname: Shi
authors.affiliation: State Key Laboratory of Plant Genomics, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, and National Center for Plant Gene Research, Beijing, China.
authors.forename: Cui
authors.identifier: 0000-0002-6665-2867
authors.initials: C
authors.lastname: Zhang
authors.affiliation: State Key Laboratory of Plant Genomics, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, and National Center for Plant Gene Research, Beijing, China.
authors.forename: Caihuan
authors.initials: C
authors.lastname: Tian
authors.affiliation: State Key Laboratory of Plant Genomics, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, and National Center for Plant Gene Research, Beijing, China.|University of Chinese Academy of Sciences, Beijing, China.
authors.forename: Jin
authors.initials: J
authors.lastname: Wang
authors.affiliation: Department of Plant Breeding and Genetics, Max Planck Institute for Plant Breeding Research, Cologne, Germany.|Agricultural Genomics Institute at Shenzhen, Chinese Academy of Agricultural Sciences, Shenzhen, China.
authors.forename: Quan
authors.identifier: 0000-0003-2912-1263
authors.initials: Q
authors.lastname: Wang
authors.affiliation: State Key Laboratory of Plant Genomics, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, and National Center for Plant Gene Research, Beijing, China.|State Key Laboratory of Crop Stress Biology in Arid Areas, Ministry of Agriculture Key Laboratory of Horticultural Plant Biology and Germplasm Innovation in Northwest China, College of Horticulture, Northwest A&F University, Yangling, Shaanxi, China.
authors.forename: Tengfei
authors.initials: T
authors.lastname: Xu
authors.affiliation: State Key Laboratory of Crop Stress Biology in Arid Areas, Ministry of Agriculture Key Laboratory of Horticultural Plant Biology and Germplasm Innovation in Northwest China, College of Horticulture, Northwest A&F University, Yangling, Shaanxi, China.
authors.forename: Yan
authors.initials: Y
authors.lastname: Xu
authors.affiliation: Developmental Biology Unit, European Molecular Biology Laboratory, Heidelberg, Germany.
authors.forename: Carolyn
authors.initials: C
authors.lastname: Ohno
authors.affiliation: Cell and Developmental Biology Department, John Innes Centre, Norwich Research Park, Norwich, United Kingdom.
authors.forename: Robert
authors.initials: R
authors.lastname: Sablowski
authors.affiliation: Developmental Biology Unit, European Molecular Biology Laboratory, Heidelberg, Germany.
authors.forename: Marcus G
authors.initials: MG
authors.lastname: Heisler
authors.affiliation: Department of Plant Breeding and Genetics, Max Planck Institute for Plant Breeding Research, Cologne, Germany.
authors.forename: Klaus
authors.initials: K
authors.lastname: Theres
authors.affiliation: State Key Laboratory of Plant Genomics, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, and National Center for Plant Gene Research, Beijing, China.|Frontier Laboratory of Crop Design, Beijing, China.
authors.forename: Ying
authors.initials: Y
authors.lastname: Wang
authors.affiliation: State Key Laboratory of Plant Genomics, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, and National Center for Plant Gene Research, Beijing, China.
authors.forename: Yuling
authors.identifier: 0000-0002-1189-1676
authors.initials: Y
authors.lastname: Jiao
mesh_terms: D000483:Alleles; D017360:Arabidopsis / Q000235:genetics* / Q000254:growth & development; D029681:Arabidopsis Proteins / Q000235:genetics; D002454:Cell Differentiation; D019070:Cell Lineage; D047369:Chromatin Immunoprecipitation; D018506:Gene Expression Regulation, Plant; D017343:Genes, Plant; D005838:Genotype; D007210:Indoleacetic Acids / Q000378:metabolism; D018519:Meristem / Q000166:cytology*; D010641:Phenotype; D018515:Plant Leaves / Q000254:growth & development; D018520:Plant Shoots / Q000254:growth & development*; D030821:Plants, Genetically Modified / Q000254:growth & development; D015854:Up-Regulation
chemical_list: D029681:Arabidopsis Proteins; D007210:Indoleacetic Acids