title: BLADE-ON-PETIOLE1 and  2 regulate Arabidopsis inflorescence architecture in conjunction with homeobox genes KNAT6 and ATH1.
abstract: Inflorescence architecture varies widely among flowering plants, serving to optimize the display of flowers for reproductive success. In Arabidopsis thaliana, internode elongation begins at the floral transition, generating a regular spiral arrangement of upwardly-oriented flowers on the primary stem. Post-elongation, differentiation of lignified interfascicular fibers in the stem provides mechanical support. Correct inflorescence patterning requires two interacting homeodomain transcription factors: the KNOTTED1-like protein BREVIPEDICELLUS (BP) and its BEL1-like interaction partner PENNYWISE (PNY). Mutations in BP and PNY cause short internodes, irregular spacing and/or orientation of lateral organs, and altered lignin deposition in stems. Recently, we showed that these defects are caused by the misexpression of lateral organ boundary genes, BLADE-ON-PETIOLE1 (BOP1) and BOP2, which function downstream of BP-PNY in an antagonistic fashion. BOP1/2 gain-of-function in stems promotes expression of the boundary gene KNOTTED1-LIKE FROM ARABIDOPSIS THALIANA6 (KNAT6) and shown here, ARABIDOPSIS THALIANA HOMEOBOX GENE1 (ATH1), providing KNAT6 with a BEL1-like co-factor. Our further analyses show that defects caused by BOP1/2 gain-of-function require both KNAT6 and ATH1. These data reveal how BOP1/2-dependent activation of a boundary module in stems exerts changes in inflorescence architecture.
authors: Department of Biology, Carleton University, Ottawa, ON, Canada.
authors: Madiha
authors: M
authors: Khan
authors: Paul
authors: P
authors: Tabb
authors: Shelley R
authors: SR
authors: Hepworth
mesh_terms: D017360:Arabidopsis / Q000033:anatomy & histology* / Q000235:genetics* / Q000254:growth & development; D029681:Arabidopsis Proteins / Q000235:genetics* / Q000378:metabolism; D019521:Body Patterning / Q000235:genetics; D018506:Gene Expression Regulation, Plant; D020868:Gene Silencing; D017343:Genes, Plant / Q000235:genetics*; D018398:Homeodomain Proteins / Q000235:genetics / Q000378:metabolism; D056626:Inflorescence / Q000033:anatomy & histology* / Q000235:genetics*; D008954:Models, Biological; D010641:Phenotype; D018547:Plant Stems / Q000166:cytology / Q000235:genetics / Q000254:growth & development; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism
chemical_list: D029681:Arabidopsis Proteins; C496963:BOP1 protein, Arabidopsis; C506721:BOP2 protein, Arabidopsis; D018398:Homeodomain Proteins; C092852:KNAT5 protein, Arabidopsis; C491111:KNAT6 protein, Arabidopsis; D012333:RNA, Messenger; D014157:Transcription Factors