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Hajheidari M, Wang Y, Bhatia N, Vuolo F, Franco-Zorrilla JM, Karady M, Mentink RA, Wu A, Oluwatobi BR, Müller B, Dello Ioio R, Laurent S, Ljung K, Huijser P, Gan X, Tsiantis M. Autoregulation of RCO by Low-Affinity Binding Modulates Cytokinin Action and Shapes Leaf Diversity. Curr Biol 2019; 29:4183-4192.e6. [PMID: 31761704 DOI: 10.1016/j.cub.2019.10.040] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2019] [Revised: 10/08/2019] [Accepted: 10/21/2019] [Indexed: 11/28/2022]
Abstract
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, the REDUCED COMPLEXITY (RCO) homeodomain protein evolved via gene duplication and acquired a novel expression domain that contributed to leaf shape diversity. However, the molecular pathways through which RCO regulates leaf growth are unknown. A key question is to identify genome-wide transcriptional targets of RCO and the DNA sequences to which RCO binds. We investigate this question using Cardamine hirsuta, which has complex leaves, and its relative Arabidopsis thaliana, which evolved simple leaves through loss of RCO. We demonstrate that RCO directly regulates genes controlling homeostasis of the hormone cytokinin to repress growth at the leaf base. Elevating cytokinin signaling in the RCO expression domain is sufficient to both transform A. thaliana simple leaves into complex ones and partially bypass the requirement for RCO in C. hirsuta complex leaf development. We also identify RCO as its own target gene. RCO directly represses its own transcription via an array of low-affinity binding sites, which evolved after RCO duplicated from its progenitor sequence. This autorepression is required to limit RCO expression. Thus, evolution of low-affinity binding sites created a negative autoregulatory loop that facilitated leaf shape evolution by defining RCO expression and fine-tuning cytokinin activity. In summary, we identify a transcriptional mechanism through which conflicts between novelty and pleiotropy are resolved during evolution and lead to morphological differences between species.
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Affiliation(s)
- Mohsen Hajheidari
- Department of Comparative Development and Genetics, Max Planck Institute for Plant Breeding Research, Carl-von-Linné-Weg 10, 50829 Cologne, Germany
| | - Yi Wang
- Department of Comparative Development and Genetics, Max Planck Institute for Plant Breeding Research, Carl-von-Linné-Weg 10, 50829 Cologne, Germany
| | - Neha Bhatia
- Department of Comparative Development and Genetics, Max Planck Institute for Plant Breeding Research, Carl-von-Linné-Weg 10, 50829 Cologne, Germany
| | - Francesco Vuolo
- Department of Comparative Development and Genetics, Max Planck Institute for Plant Breeding Research, Carl-von-Linné-Weg 10, 50829 Cologne, Germany
| | - José Manuel Franco-Zorrilla
- Unidad de Genómica and Departamento de Genética Molecular de Plantas, Centro Nacional de Biotecnología-Consejo Superior de Investigaciones Científicas, Calle Darwin 3, 28049 Madrid, Spain
| | - Michal Karady
- Umeå Plant Science Centre, Department of Forest Genetics and Plant Physiology, Swedish University of Agricultural Sciences, 901 83 Umeå, Sweden
| | - Remco A Mentink
- Department of Comparative Development and Genetics, Max Planck Institute for Plant Breeding Research, Carl-von-Linné-Weg 10, 50829 Cologne, Germany
| | - Anhui Wu
- Department of Comparative Development and Genetics, Max Planck Institute for Plant Breeding Research, Carl-von-Linné-Weg 10, 50829 Cologne, Germany
| | - Bello Rilwan Oluwatobi
- Department of Comparative Development and Genetics, Max Planck Institute for Plant Breeding Research, Carl-von-Linné-Weg 10, 50829 Cologne, Germany
| | - Bruno Müller
- Leibniz Institute of Plant Genetics and Crop Plant Research, Correnstr. 3, 06466 Seeland, Gatersleben, Germany
| | - Raffaele Dello Ioio
- Department of Biology and Biotechnology, Laboratory of Functional Genomics and Proteomics of Model Systems, Sapienza University of Rome, Via dei Sardi 70, 00185 Rome, Italy
| | - Stefan Laurent
- Department of Comparative Development and Genetics, Max Planck Institute for Plant Breeding Research, Carl-von-Linné-Weg 10, 50829 Cologne, Germany
| | - Karin Ljung
- Umeå Plant Science Centre, Department of Forest Genetics and Plant Physiology, Swedish University of Agricultural Sciences, 901 83 Umeå, Sweden
| | - Peter Huijser
- Department of Comparative Development and Genetics, Max Planck Institute for Plant Breeding Research, Carl-von-Linné-Weg 10, 50829 Cologne, Germany
| | - Xiangchao Gan
- Department of Comparative Development and Genetics, Max Planck Institute for Plant Breeding Research, Carl-von-Linné-Weg 10, 50829 Cologne, Germany
| | - Miltos Tsiantis
- Department of Comparative Development and Genetics, Max Planck Institute for Plant Breeding Research, Carl-von-Linné-Weg 10, 50829 Cologne, Germany.
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