title: Arabidopsis floral phytomer development: auxin response relative to biphasic modes of organ initiation.
abstract: In the Arabidopsis inflorescence meristem (IM), auxin is considered a prepatterning signal for floral primordia, whereas a centripetal mode of positional information for floral organ identity is inherent to the ABCE model. However, spatio-temporal patterns of organ initiation in each whorl at the earliest initiation stages are largely unknown. Evidence suggests that initial flower development occurs along an abaxial/adaxial axis and conforms to phytomer theory. Use of the founder cell marker DORNRÖSCHEN-LIKE (DRNL) as a tool in leafy, puchi, and apetala 1 cauliflower mutant backgrounds suggests that bract founder cells are marked at the IM periphery. The DRNL transcription domain in the wild-type IM is spatially discrete from DR5 expression, suggesting that bract initiation is independent of canonical auxin response. When bracts develop in lfy and puchi mutant floral primordia the initiation of lateral sepals precedes the specification of medial sepals compared with wild type, showing an interplay between bract and abaxial sepal founder cell recruitment. In the perianthia (pan) mutant background, DRNL expression indicates that a radial outer whorl arrangement derives from splitting of sepal founder cell populations at abaxial and adaxial positions. This splitting of incipient sepal primordia is partially dependent on PRESSED FLOWER (PRS) activity and implies that sepal specification is independent of WUSCHEL and CLAVATA3 expression, as both marker genes only regain activity in stage-2 flowers, when patterning of inner floral organs switches to a centripetal mode. The transition from an initially abaxial/adaxial into a centripetal patterning programme, and its timing represent an adaptive trait that possibly contributes to variation in floral morphology, especially unidirectional organ initiation.
authors.affiliation: Institute of Developmental Biology, Cologne Biocenter, University of Cologne, Cologne, Germany. john.chandler@uni-koeln.de.
authors.forename: J W
authors.initials: JW
authors.lastname: Chandler
authors.affiliation: Institute of Developmental Biology, Cologne Biocenter, University of Cologne, Cologne, Germany.
authors.forename: W
authors.initials: W
authors.lastname: Werr
mesh_terms: D017360:Arabidopsis / Q000235:genetics / Q000254:growth & development* / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism; D035264:Flowers / Q000235:genetics / Q000254:growth & development / Q000378:metabolism; D007210:Indoleacetic Acids / Q000378:metabolism*; D018519:Meristem / Q000235:genetics / Q000254:growth & development / Q000378:metabolism; D016133:Polymerase Chain Reaction; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism
chemical_list: D029681:Arabidopsis Proteins; D007210:Indoleacetic Acids; D014157:Transcription Factors; C517039:DRNL protein, Arabidopsis
keywords: Centripetal flower development; DORNRÖSCHEN-LIKE; bract.; floral meristem; founder cells; stem-cell niche
references.citation: Development. 2007 May;134(9):1653-62
references.pmid: 17376809
references.citation: Plant Cell. 2009 Aug;21(8):2269-83
references.pmid: 19717616
references.citation: Nature. 2001 Jan 25;409(6819):469-71
references.pmid: 11206529
references.citation: Dev Genet. 1999 Sep;25(3):280-90
references.pmid: 10528268
references.citation: Development. 2000 Feb;127(4):725-34
references.pmid: 10648231
references.citation: Plant Cell. 2009 May;21(5):1360-72
references.pmid: 19482972
references.citation: Plant Cell. 1990 Aug;2(8):755-67
references.pmid: 2152125
references.citation: Plant Physiol. 2003 Mar;131(3):911-26
references.pmid: 12644644
references.citation: Development. 2004 Dec;131(24):6083-91
references.pmid: 15537689
references.citation: Plant Cell Rep. 2013 Jan;32(1):45-59
references.pmid: 23011125
references.citation: Plant Physiol. 2009 Feb;149(2):841-50
references.pmid: 19073779
references.citation: Arabidopsis Book. 2010;8:e0127
references.pmid: 22303253
references.citation: Nature. 1991 Sep 5;353(6339):31-7
references.pmid: 1715520
references.citation: Genesis. 2003 May;36(1):25-33
references.pmid: 12748964
references.citation: Plant Cell. 2010 Mar;22(3):565-78
references.pmid: 20305121
references.citation: Proc Natl Acad Sci U S A. 2009 Mar 24;106(12):4941-6
references.pmid: 19258454
references.citation: Plant Cell. 2012 Feb;24(2):519-35
references.pmid: 22374393
references.citation: Cell. 1992 May 29;69(5):843-59
references.pmid: 1350515
references.citation: Plant Mol Biol. 2003 Jul;52(4):831-41
references.pmid: 13677470
references.citation: Curr Opin Plant Biol. 2007 Feb;10(1):44-51
references.pmid: 17157052
references.citation: Development. 2004 Jun;131(12):2827-39
references.pmid: 15169755
references.citation: Development. 1996 Apr;122(4):1093-102
references.pmid: 8620836
references.citation: J Exp Bot. 2006;57(3):571-80
references.pmid: 16377735
references.citation: Development. 2013 Jan 1;140(1):185-94
references.pmid: 23175631
references.citation: Development. 2004 Sep;131(17):4225-37
references.pmid: 15280208
references.citation: Nature. 2003 Nov 20;426(6964):255-60
references.pmid: 14628043
references.citation: Development. 1996 Jan;122(1):87-96
references.pmid: 8565856
references.citation: Plant Cell. 2011 Jun;23(6):2125-42
references.pmid: 21719692
references.citation: Genes Dev. 2006 Jul 1;20(13):1790-9
references.pmid: 16818609
references.citation: Nature. 1996 Jan 4;379(6560):66-9
references.pmid: 8538741
references.citation: Curr Biol. 2005 Nov 8;15(21):1899-911
references.pmid: 16271866
references.citation: Curr Biol. 2001 Aug 21;11(16):1251-60
references.pmid: 11525739
references.citation: Plant Cell. 1999 Jan;11(1):69-86
references.pmid: 9878633
references.citation: Curr Opin Plant Biol. 2001 Feb;4(1):86-91
references.pmid: 11163173
references.citation: Curr Opin Plant Biol. 2010 Feb;13(1):108-14
references.pmid: 19853497
references.citation: Cell Mol Life Sci. 2012 Nov;69(22):3807-18
references.pmid: 22573183
references.citation: Planta. 2006 Jan;223(2):315-28
references.pmid: 16208486
references.citation: PLoS One. 2012;7(1):e28762
references.pmid: 22291882
references.citation: Ann Bot. 2007 Aug;100(2):155-63
references.pmid: 17616563
references.citation: Am J Bot. 2000 Oct;87(10):1385-407
references.pmid: 11034916
references.citation: Genes Dev. 1999 Feb 1;13(3):334-44
references.pmid: 9990857
references.citation: Genes Dev. 2001 Dec 15;15(24):3355-64
references.pmid: 11751640
references.citation: Plant Cell. 2004 Jan;16(1):74-87
references.pmid: 14671026
references.citation: Plant Cell. 2008 May;20(5):1217-30
references.pmid: 18469164
references.citation: Trends Plant Sci. 2011 Nov;16(11):607-13
references.pmid: 21924666
references.citation: BMC Plant Biol. 2010 Jun 28;10:131
references.pmid: 20584289
references.citation: Science. 1999 Mar 19;283(5409):1911-4
references.pmid: 10082464
references.citation: Am J Bot. 2001 Jul;88(7):1164-80
references.pmid: 11454616
references.citation: Development. 1996 Apr;122(4):1261-9
references.pmid: 8620853
references.citation: Plant Cell. 1991 Aug;3(8):771-781
references.pmid: 12324613
references.citation: Dev Biol. 2000 Feb 15;218(2):341-53
references.pmid: 10656774
references.citation: Plant J. 1998 Sep;15(6):799-804
references.pmid: 9807818
references.citation: Plant Cell. 1989 Jan;1(1):37-52
references.pmid: 2535466
references.citation: Plant Mol Biol. 2011 May;76(1-2):171-85
references.pmid: 21547450
references.citation: Front Plant Sci. 2011 Nov 21;2:79
references.pmid: 22645551