title: MS23, a master basic helix-loop-helix factor, regulates the specification and development of the tapetum in maize.
abstract: Successful male gametogenesis involves orchestration of sequential gene regulation for somatic differentiation in pre-meiotic anthers. We report here the cloning of Male Sterile23 (Ms23), encoding an anther-specific predicted basic helix-loop-helix (bHLH) transcription factor required for tapetal differentiation; transcripts localize initially to the precursor secondary parietal cells then predominantly to daughter tapetal cells. In knockout ms23-ref mutant anthers, five instead of the normal four wall layers are observed. Microarray transcript profiling demonstrates a more severe developmental disruption in ms23-ref than in ms32 anthers, which possess a different bHLH defect. RNA-seq and proteomics data together with yeast two-hybrid assays suggest that MS23 along with MS32, bHLH122 and bHLH51 act sequentially as either homo- or heterodimers to choreograph tapetal development. Among them, MS23 is the earliest-acting factor, upstream of bHLH51 and bHLH122, controlling tapetal specification and maturation. By contrast, MS32 is constitutive and independently regulated and is required later than MS23 in tapetal differentiation.
authors.affiliation: Department of Biology, Stanford University, Stanford, CA 94305, USA gnan@stanford.edu walbot@stanford.edu.
authors.forename: Guo-Ling
authors.identifier: 0000-0002-1286-0249
authors.initials: GL
authors.lastname: Nan
authors.affiliation: Department of Plant and Soil Sciences and Delaware Biotechnology Institute, University of Delaware, Newark, DE 19716, USA.|Department of Biology, South University of Science and Technology, Shenzhen 518055, China.
authors.forename: Jixian
authors.identifier: 0000-0002-7906-4976
authors.initials: J
authors.lastname: Zhai
authors.affiliation: Department of Plant and Soil Sciences and Delaware Biotechnology Institute, University of Delaware, Newark, DE 19716, USA.
authors.forename: Siwaret
authors.identifier: 0000-0002-2964-1886
authors.initials: S
authors.lastname: Arikit
authors.affiliation: Department of Biology, Stanford University, Stanford, CA 94305, USA.
authors.forename: Darren
authors.initials: D
authors.lastname: Morrow
authors.affiliation: Department of Biology, Stanford University, Stanford, CA 94305, USA.
authors.forename: John
authors.identifier: 0000-0002-2445-8273
authors.initials: J
authors.lastname: Fernandes
authors.affiliation: Department of Biology, Stanford University, Stanford, CA 94305, USA.
authors.forename: Lan
authors.initials: L
authors.lastname: Mai
authors.affiliation: Department of Biology, Stanford University, Stanford, CA 94305, USA.
authors.forename: Nhi
authors.initials: N
authors.lastname: Nguyen
authors.affiliation: Department of Plant and Soil Sciences and Delaware Biotechnology Institute, University of Delaware, Newark, DE 19716, USA.
authors.forename: Blake C
authors.identifier: 0000-0003-3436-6097
authors.initials: BC
authors.lastname: Meyers
authors.affiliation: Department of Biology, Stanford University, Stanford, CA 94305, USA gnan@stanford.edu walbot@stanford.edu.
authors.forename: Virginia
authors.identifier: 0000-0002-1596-7279
authors.initials: V
authors.lastname: Walbot
mesh_terms: D051792:Basic Helix-Loop-Helix Proteins / Q000502:physiology*; D002454:Cell Differentiation / Q000235:genetics; D035264:Flowers / Q000196:embryology*; D056130:Gametogenesis, Plant / Q000235:genetics; D020869:Gene Expression Profiling; D018507:Gene Expression Regulation, Developmental; D018506:Gene Expression Regulation, Plant; D053263:Gene Regulatory Networks; D008540:Meiosis / Q000235:genetics; D010940:Plant Proteins / Q000502:physiology; D030821:Plants, Genetically Modified; D003313:Zea mays / Q000196:embryology / Q000235:genetics
chemical_list: D051792:Basic Helix-Loop-Helix Proteins; D010940:Plant Proteins
keywords: Pre-meiotic male reproduction; Proteome; Regulatory hierarchy; Transcriptome