title: BRC1expression regulates bud activation potential but is not necessary or sufficient for bud growth inhibition inArabidopsis.
abstract: The degree of shoot branching inArabidopsisis determined by the activation of axillary buds. Bud activity is regulated by diverse environmental and developmental signals, often mediated via plant hormones, including auxin, strigolactone and cytokinin. The transcription factorBRANCHED1(BRC1) has been proposed to integrate these regulatory signals. This idea is based on increased branching inbrc1mutants, the effects of bud-regulating hormones onBRC1expression, and a general correlation betweenBRC1expression and bud growth inhibition. These data demonstrate the important role ofBRC1in shoot branching, but here we show that inArabidopsisthis correlation can be broken. Buds lackingBRC1expression can remain inhibited and sensitive to inhibition by strigolactone. Furthermore, buds with highBRC1transcript levels can be active. Based on these data, we propose thatBRC1regulates bud activation potential in concert with an auxin transport-based mechanism underpinning bud activity. In the context of strigolactone-mediated bud regulation, our data suggest a coherent feed-forward loop in which strigolactone treatment reduces the probability of bud activation by parallel effects onBRC1transcription and the shoot auxin transport network.
authors.affiliation: Sainsbury Laboratory, University of Cambridge, Bateman Street, Cambridge CB2 1LR, UK.
authors.forename: Madeleine
authors.identifier: 0000-0002-8924-3943
authors.initials: M
authors.lastname: Seale
authors.affiliation: Sainsbury Laboratory, University of Cambridge, Bateman Street, Cambridge CB2 1LR, UK.
authors.forename: Tom
authors.identifier: 0000-0003-1612-4019
authors.initials: T
authors.lastname: Bennett
authors.affiliation: Sainsbury Laboratory, University of Cambridge, Bateman Street, Cambridge CB2 1LR, UK ol235@cam.ac.uk.
authors.forename: Ottoline
authors.identifier: 0000-0003-2161-3829
authors.initials: O
authors.lastname: Leyser
mesh_terms: D017360:Arabidopsis / Q000187:drug effects / Q000196:embryology* / Q000235:genetics*; D029681:Arabidopsis Proteins / Q000235:genetics* / Q000378:metabolism; D004843:Epistasis, Genetic / Q000187:drug effects; D018507:Gene Expression Regulation, Developmental / Q000187:drug effects; D018506:Gene Expression Regulation, Plant / Q000187:drug effects; D007210:Indoleacetic Acids / Q000494:pharmacology; D007783:Lactones / Q000494:pharmacology; D009154:Mutation / Q000235:genetics; D018520:Plant Shoots / Q000187:drug effects / Q000196:embryology* / Q000235:genetics*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects / Q000235:genetics; D014157:Transcription Factors / Q000235:genetics* / Q000378:metabolism
chemical_list: D029681:Arabidopsis Proteins; C521259:BRC1 protein, Arabidopsis; D007210:Indoleacetic Acids; D007783:Lactones; D012333:RNA, Messenger; D014157:Transcription Factors
keywords: Auxin; BRANCHED1; Bud growth inhibition; Shoot branching; Strigolactone