title: Lateral root formation and growth of Arabidopsis is redundantly regulated by cytokinin metabolism and signalling genes.
abstract: The plant root system is important for the uptake of water and nutrients and the anchoring of plants in the soil. Lateral roots (LRs) contribute considerably to root system architecture. Their post-embryonic formation is regulated by hormones and environmental cues. The hormone cytokinin influences LR formation and growth in Arabidopsis thaliana on different levels by disturbing cell division activity and pattern formation. This includes inhibition of the first formative cell division of pericycle founder cells and inhibition of the outgrowth of young LR primordia. Mutant analysis revealed that the cytokinin biosynthesis genes IPT3 and IPT5 and all three cytokinin receptor genes (AHK2, AHK3, and CRE1/AHK4) act redundantly during LR initiation. Mutation of AHK2 and AHK3 caused increased auxin sensitivity of LR formation, corroborating the functional relevance of auxin-cytokinin interaction during LR formation. In contrast, LR development of cytokinin receptor mutants in response to other hormones was mostly similar to that of the wild type, which is consistent with separate response pathways. A noticeable exception was an increased sensitivity of LR elongation to brassinolide in ahk2 ahk3 mutants indicating antagonistic action of cytokinin and brassinosteroid. It is proposed that the multilevel redundancy of the cytokinin system in modulating LR formation reflects its role in mediating environmental cues.
authors.affiliation: Institute of Biology/Applied Genetics, Dahlem Centre of Plant Sciences (DCPS), Freie Universität Berlin, Albrecht-Thaer-Weg 6, D-14195 Berlin, Germany.
authors.forename: Ling
authors.initials: L
authors.lastname: Chang
authors.forename: Eswarayya
authors.initials: E
authors.lastname: Ramireddy
authors.forename: Thomas
authors.initials: T
authors.lastname: Schmülling
mesh_terms: D017360:Arabidopsis / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D053898:Biosynthetic Pathways; D003583:Cytokinins / Q000096:biosynthesis*; D018507:Gene Expression Regulation, Developmental; D018506:Gene Expression Regulation, Plant; D018517:Plant Roots / Q000235:genetics / Q000254:growth & development* / Q000378:metabolism; D015398:Signal Transduction
chemical_list: D029681:Arabidopsis Proteins; D003583:Cytokinins
keywords: Arabidopsis thaliana; auxin; cytokinin; hormonal cross-talk; lateral root development; root system architecture.
references.citation: Plant Cell. 2002 Oct;14(10):2339-51
references.pmid: 12368490
references.citation: Genes Dev. 2000 Dec 1;14(23):2938-43
references.pmid: 11114883
references.citation: Planta. 1974 Jan;121(3):253-61
references.pmid: 24442804
references.citation: Plant J. 2004 Apr;38(2):203-14
references.pmid: 15078325
references.citation: Plant Cell. 2005 Nov;17(11):3007-18
references.pmid: 16227453
references.citation: Development. 2004 Jan;131(2):389-400
references.pmid: 14681187
references.citation: Plant Cell. 2009 Oct;21(10):3152-69
references.pmid: 19837870
references.citation: Planta. 2001 Nov;214(1):30-6
references.pmid: 11762168
references.citation: Plant Cell. 2006 Jan;18(1):40-54
references.pmid: 16361392
references.citation: Plant Mol Biol. 2009 Mar;69(4):361-73
references.pmid: 18688730
references.citation: Plant Physiol. 1995 Sep;109(1):7-13
references.pmid: 12228579
references.citation: J Exp Bot. 2001 Mar;52(Spec Issue):403-11
references.pmid: 11326046
references.citation: Plant Cell. 2010 Nov;22(11):3560-73
references.pmid: 21097710
references.citation: Plant Cell Physiol. 2006 Aug;47(8):1112-23
references.pmid: 16854941
references.citation: Plant J. 2002 Jan;29(2):153-68
references.pmid: 11862947
references.citation: Plant Physiol. 2010 May;153(1):34-40
references.pmid: 20219832
references.citation: Plant Cell. 2012 Oct;24(10):3967-81
references.pmid: 23054471
references.citation: Wiley Interdiscip Rev Dev Biol. 2012 May-Jun;1(3):329-43
references.pmid: 23801487
references.citation: Proc Natl Acad Sci U S A. 2010 Feb 9;107(6):2705-10
references.pmid: 20133796
references.citation: Plant Cell. 2004 Jun;16(6):1365-77
references.pmid: 15155880
references.citation: Plant Physiol. 2008 Jul;147(3):1380-95
references.pmid: 18502977
references.citation: Plant Physiol. 2013 Mar;161(3):1066-75
references.pmid: 23355633
references.citation: Development. 1997 Jan;124(1):33-44
references.pmid: 9006065
references.citation: Plant Cell. 2005 Feb;17(2):444-63
references.pmid: 15659631
references.citation: Plant Cell. 2001 Apr;13(4):843-52
references.pmid: 11283340
references.citation: PLoS One. 2013;8(2):e56370
references.pmid: 23457561
references.citation: Plant Cell. 2010 Dec;22(12):3905-20
references.pmid: 21148816
references.citation: Plant Cell. 2012 Jan;24(1):4-14
references.pmid: 22227889
references.citation: Plant J. 2004 Jan;37(1):128-38
references.pmid: 14675438
references.citation: Trends Plant Sci. 2009 Jul;14(7):399-408
references.pmid: 19559642
references.citation: Science. 2006 Jan 6;311(5757):94-8
references.pmid: 16400151
references.citation: Plant J. 2011 Jul;67(1):157-68
references.pmid: 21426428
references.citation: Plant Cell Physiol. 2004 Aug;45(8):1053-62
references.pmid: 15356331
references.citation: Plant Cell Environ. 2009 Sep;32(9):1147-60
references.pmid: 19183294
references.citation: Plant Physiol. 2000 Dec;124(4):1706-17
references.pmid: 11115887
references.citation: Cell. 2003 Nov 26;115(5):591-602
references.pmid: 14651850
references.citation: Plant J. 2008 Jul;55(2):335-47
references.pmid: 18435826
references.citation: Mol Plant. 2008 Mar;1(2):321-37
references.pmid: 19825543
references.citation: Curr Opin Plant Biol. 2010 Dec;13(6):677-83
references.pmid: 20934368
references.citation: Plant Cell. 2012 Jan;24(1):15-20
references.pmid: 22227890
references.citation: Curr Opin Plant Biol. 2009 Oct;12(5):527-38
references.pmid: 19740698
references.citation: Proc Natl Acad Sci U S A. 2001 Aug 28;98(18):10487-92
references.pmid: 11504909
references.citation: Proc Natl Acad Sci U S A. 2006 Oct 31;103(44):16598-603
references.pmid: 17062755
references.citation: Plant J. 2003 Feb;33(3):543-55
references.pmid: 12581312
references.citation: Plant Cell Physiol. 2007 Jan;48(1):84-96
references.pmid: 17132632
references.citation: Plant Mol Biol. 2009 Mar;69(4):437-49
references.pmid: 18982413
references.citation: Plant Cell Environ. 2005 Jan;28(1):67-77
references.pmid: 16021787
references.citation: BMC Plant Biol. 2012 Jul 23;12:112
references.pmid: 22824128
references.citation: EMBO J. 1987 Dec 20;6(13):3901-7
references.pmid: 3327686
references.citation: Plant J. 2011 Oct;68(1):1-10
references.pmid: 21645147
references.citation: Plant Cell. 2007 Dec;19(12):3889-900
references.pmid: 18065686
references.citation: Plant Physiol. 2004 Apr;134(4):1624-31
references.pmid: 15047895
references.citation: Plant Physiol. 2011 Mar;155(3):1339-52
references.pmid: 21205622
references.citation: Plant Biol (Stuttg). 2006 May;8(3):371-81
references.pmid: 16807830
references.citation: Dev Cell. 2011 Oct 18;21(4):796-804
references.pmid: 21962902
references.citation: Plant Cell. 2003 Nov;15(11):2532-50
references.pmid: 14555694
references.citation: Plant Cell Physiol. 2008 Jan;49(1):47-57
references.pmid: 18037673