title: The embryonic leaf identity gene FUSCA3 regulates vegetative phase transitions by negatively modulating ethylene-regulated gene expression in Arabidopsis.
abstract: BACKGROUND
  The embryonic temporal regulator FUSCA3 (FUS3) plays major roles in the establishment of embryonic leaf identity and the regulation of developmental timing. Loss-of-function mutations of this B3 domain transcription factor result in replacement of cotyledons with leaves and precocious germination, whereas constitutive misexpression causes the conversion of leaves into cotyledon-like organs and delays vegetative and reproductive phase transitions.
  
  
  RESULTS
  Herein we show that activation of FUS3 after germination dampens the expression of genes involved in the biosynthesis and response to the plant hormone ethylene, whereas a loss-of-function fus3 mutant shows many phenotypes consistent with increased ethylene signaling. This FUS3-dependent regulation of ethylene signaling also impinges on timing functions outside embryogenesis. Loss of FUS3 function results in accelerated vegetative phase change, and this is again partially dependent on functional ethylene signaling. This alteration in vegetative phase transition is dependent on both embryonic and vegetative FUS3 function, suggesting that this important transcriptional regulator controls both embryonic and vegetative developmental timing.
  
  
  CONCLUSIONS
  The results of this study indicate that the embryonic regulator FUS3 not only controls the embryonic-to-vegetative phase transition through hormonal (ABA/GA) regulation but also functions postembryonically to delay vegetative phase transitions by negatively modulating ethylene-regulated gene expression.
authors.affiliation: Department of Cell and Systems Biology, University of Toronto, ON, Canada.
authors.forename: Shelley
authors.initials: S
authors.lastname: Lumba
authors.forename: Yuichiro
authors.initials: Y
authors.lastname: Tsuchiya
authors.forename: Frederic
authors.initials: F
authors.lastname: Delmas
authors.forename: Jodi
authors.initials: J
authors.lastname: Hezky
authors.forename: Nicholas J
authors.initials: NJ
authors.lastname: Provart
authors.forename: Qing
authors.initials: Q
authors.lastname: Shi Lu
authors.forename: Peter
authors.initials: P
authors.lastname: McCourt
authors.forename: Sonia
authors.initials: S
authors.lastname: Gazzarrini
mesh_terms: D017360:Arabidopsis / Q000235:genetics* / Q000254:growth & development / Q000378:metabolism; D005030:Ethylenes / Q000378:metabolism*; D018507:Gene Expression Regulation, Developmental; D018506:Gene Expression Regulation, Plant; D055106:Genome-Wide Association Study; D009154:Mutation; D010937:Plant Growth Regulators / Q000378:metabolism*; D018515:Plant Leaves / Q000235:genetics / Q000254:growth & development / Q000378:metabolism; D016133:Polymerase Chain Reaction; D014157:Transcription Factors / Q000378:metabolism*
chemical_list: D005030:Ethylenes; C502726:FUSCA3 protein, Arabidopsis; D010937:Plant Growth Regulators; D014157:Transcription Factors; C036216:ethylene