title: POPCORN functions in the auxin pathway to regulate embryonic body plan and meristem organization in Arabidopsis.
abstract: The shoot and root apical meristems (SAM and RAM) formed during embryogenesis are crucial for postembryonic plant development. We report the identification of POPCORN (PCN), a gene required for embryo development and meristem organization in Arabidopsis thaliana. Map-based cloning revealed that PCN encodes a WD-40 protein expressed both during embryo development and postembryonically in the SAM and RAM. The two pcn alleles identified in this study are temperature sensitive, showing defective embryo development when grown at 22°C that is rescued when grown at 29°C. In pcn mutants, meristem-specific expression of WUSCHEL (WUS), CLAVATA3, and WUSCHEL-RELATED HOMEOBOX5 is not maintained; SHOOTMERISTEMLESS, BODENLOS (BDL) and MONOPTEROS (MP) are misexpressed. Several findings link PCN to auxin signaling and meristem function: ectopic expression of DR5(rev):green fluorescent protein (GFP), pBDL:BDL-GFP, and pMP:MP-β-glucuronidase in the meristem; altered polarity and expression of pPIN1:PIN1-GFP in the apical domain of the developing embryo; and resistance to auxin in the pcn mutants. The bdl mutation rescued embryo lethality of pcn, suggesting that improper auxin response is involved in pcn defects. Furthermore, WUS, PINFORMED1, PINOID, and TOPLESS are dosage sensitive in pcn, suggesting functional interaction. Together, our results suggest that PCN functions in the auxin pathway, integrating auxin signaling in the organization and maintenance of the SAM and RAM.
authors.affiliation: Plant Biotechnology Institute, National Research Council Canada, Saskatoon, Saskatchewan, Canada.
authors.forename: Daoquan
authors.initials: D
authors.lastname: Xiang
authors.forename: Hui
authors.initials: H
authors.lastname: Yang
authors.forename: Prakash
authors.initials: P
authors.lastname: Venglat
authors.forename: Yongguo
authors.initials: Y
authors.lastname: Cao
authors.forename: Rui
authors.initials: R
authors.lastname: Wen
authors.forename: Maozhi
authors.initials: M
authors.lastname: Ren
authors.forename: Sandra
authors.initials: S
authors.lastname: Stone
authors.forename: Edwin
authors.initials: E
authors.lastname: Wang
authors.forename: Hong
authors.initials: H
authors.lastname: Wang
authors.forename: Wei
authors.initials: W
authors.lastname: Xiao
authors.forename: Dolf
authors.initials: D
authors.lastname: Weijers
authors.forename: Thomas
authors.initials: T
authors.lastname: Berleth
authors.forename: Thomas
authors.initials: T
authors.lastname: Laux
authors.forename: Gopalan
authors.initials: G
authors.lastname: Selvaraj
authors.forename: Raju
authors.initials: R
authors.lastname: Datla
mesh_terms: D000483:Alleles; D017360:Arabidopsis / Q000033:anatomy & histology / Q000196:embryology* / Q000235:genetics / Q000254:growth & development / Q000378:metabolism; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D019521:Body Patterning; D016764:Cell Polarity; D003001:Cloning, Molecular; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism; D018507:Gene Expression Regulation, Developmental; D018506:Gene Expression Regulation, Plant; D017343:Genes, Plant; D049452:Green Fluorescent Proteins / Q000378:metabolism; D018398:Homeodomain Proteins / Q000235:genetics / Q000378:metabolism; D007210:Indoleacetic Acids / Q000378:metabolism; D018519:Meristem / Q000166:cytology / Q000196:embryology / Q000254:growth & development* / Q000378:metabolism; D008855:Microscopy, Electron, Scanning; D009154:Mutation; D054730:Protein Interaction Domains and Motifs; D017346:Protein Serine-Threonine Kinases / Q000235:genetics / Q000378:metabolism; D012639:Seeds / Q000235:genetics / Q000254:growth & development* / Q000378:metabolism / Q000648:ultrastructure; D015398:Signal Transduction; D013696:Temperature; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism; D020798:Two-Hybrid System Techniques
chemical_list: D029681:Arabidopsis Proteins; D004268:DNA-Binding Proteins; D049452:Green Fluorescent Proteins; D018398:Homeodomain Proteins; D007210:Indoleacetic Acids; D017346:Protein Serine-Threonine Kinases; D014157:Transcription Factors; C118167:AT2G27250 protein, Arabidopsis; C111371:MONOPTEROS protein, Arabidopsis; C097496:STM protein, Arabidopsis; C116421:WUSCHEL protein, Arabidopsis; C511291:At1g15750 protein, Arabidopsis; C405165:PINOID protein, Arabidopsis