title: EOBII controls flower opening by functioning as a general transcriptomic switch.
abstract: R2R3-MYB transcription factors (TFs) are involved in diverse aspects of plant biology. Recently an R2R3-MYB was identified in Petunia x hybrida line P720 to have a role in the transcriptional regulation of floral volatile production. We propose a more foundational role for the R2R3-MYB TF EMISSION OF BENZENOIDS II (EOBII). The homolog of EOBII was isolated and characterized from P. x hybrida 'Mitchell Diploid' (MD) and Nicotiana attenuata. For both MD and N. attenuata, EOBII transcript accumulates to high levels in floral tissue with maximum accumulation at flower opening. When EOBII transcript levels are severely reduced using a stable RNAi (ir) approach in MD and N. attenuata, ir-EOBII flowers fail to enter anthesis and prematurely senesce. Transcript accumulation analysis demonstrated core phenylpropanoid pathway transcripts and cell wall modifier transcript levels are altered in ir-EOBII flowers. These flowers can be partially complemented by feeding with a sucrose, t-cinnamic acid, and gibberellic acid solution; presumably restoring cellular aspects sufficient for flower opening. Additionally, if ethylene sensitivity is blocked in either MD or N. attenuata, ir-EOBII flowers enter anthesis. These experiments demonstrate one R2R3-MYB TF can control a highly dynamic process fundamental to sexual reproduction in angiosperms: the opening of flowers.
authors.affiliation: Department of Environmental Horticulture, University of Florida Gainesville, Florida 32611, USA.
authors.forename: Thomas A
authors.initials: TA
authors.lastname: Colquhoun
authors.forename: Michael L
authors.initials: ML
authors.lastname: Schwieterman
authors.forename: Ashlyn E
authors.initials: AE
authors.lastname: Wedde
authors.forename: Bernardus C J
authors.initials: BC
authors.lastname: Schimmel
authors.forename: Danielle M
authors.initials: DM
authors.lastname: Marciniak
authors.forename: Julian C
authors.initials: JC
authors.lastname: Verdonk
authors.forename: Joo Young
authors.initials: JY
authors.lastname: Kim
authors.forename: Youngjoo
authors.initials: Y
authors.lastname: Oh
authors.forename: Ivan
authors.initials: I
authors.lastname: Gális
authors.forename: Ian T
authors.initials: IT
authors.lastname: Baldwin
authors.forename: David G
authors.initials: DG
authors.lastname: Clark
mesh_terms: D004171:Diploidy; D005030:Ethylenes / Q000494:pharmacology; D035264:Flowers / Q000187:drug effects / Q000235:genetics* / Q000254:growth & development / Q000502:physiology*; D020869:Gene Expression Profiling; D018506:Gene Expression Regulation, Plant / Q000187:drug effects; D005816:Genetic Complementation Test; D008969:Molecular Sequence Data; D032306:Petunia / Q000187:drug effects / Q000235:genetics* / Q000254:growth & development / Q000502:physiology*; D010641:Phenotype; D010802:Phylogeny; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism*; D011401:Promoter Regions, Genetic / Q000235:genetics; D034622:RNA Interference / Q000187:drug effects; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014026:Nicotiana / Q000187:drug effects / Q000235:genetics
chemical_list: D005030:Ethylenes; D010940:Plant Proteins; D012333:RNA, Messenger; C036216:ethylene