Autoregulation of RCO by Low-Affinity Binding Modulates Cytokinin Action and Shapes Leaf Diversity

• DOI: 10.1016/j.cub.2019.10.040
• Publication Date: 2019-11-21T15:48:47Z
• Authors: Mohsen Hajheidari; Yi Wang; Neha Bhatia; Francesco Vuolo; José Manuel Franc...; Michal Karady; Remco A. Mentink; Anhui Wu; Bello Rilwan Oluw...; Bruno Müller; Raffaele Dello Ioio; Stefan Laurent; Karin Ljung; Peter Huijser; Xiangchao Gan; Miltos Tsiantis
• Keywords: 0301 basic medicine; Cytokinins; Complex leaves; Arabidopsis; Cytokinin; Evolution, Molecular; 03 medical and health sciences; Gene Expression Regulation, Plant; Gene Duplication; cis-regulatory evolution; complex leaves; cytokinin; evo-devo; leaf shape; low-affinity binding sites; plant homeobox gene; RCO; REDUCED COMPLEXITY; Homeostasis; Cis-regulatory evolution; Plant homeobox gene; Plant Proteins; 2. Zero hunger; Arabidopsis Proteins; Reduced complexity; Evo-devo; REDUCED COMPLEXITY; 15. Life on land; Low-affinity binding sites; Plant Leaves; RCO; Cardamine; Plant homeobox gene; Evo-devo; Low-affinity binding sites; Cis-regulatory evolution; Leaf shape; Complex leaves; Reduced complexity; RCO; Cytokinin; Leaf shape; Transcription Factors

Mechanisms through which the evolution of gene regulation causes morphological diversity are largely unclear. The tremendous shape variation among plant leaves offers attractive opportunities to address this question. In cruciferous plants, REDUCED COMPLEXITY (RCO) homeodomain protein evolved via duplication and acquired a novel expression domain that contributed leaf diversity. However, molecular pathways RCO regulates growth unknown. A key question is identify genome-wide transcriptional targets DNA sequences binds. We investigate using Cardamine hirsuta, has complex leaves, its relative Arabidopsis thaliana, simple loss RCO. demonstrate directly genes controlling homeostasis hormone cytokinin repress at base. Elevating signaling in sufficient both transform A. thaliana into ones partially bypass requirement for C. hirsuta development. also as own target gene. represses transcription an array low-affinity binding sites, after duplicated from progenitor sequence. This autorepression required limit expression. Thus, sites created negative autoregulatory loop facilitated by defining fine-tuning activity. summary, we mechanism conflicts between novelty pleiotropy resolved during lead differences species.