The CLAVATA1-related BAM1, BAM2 and BAM3 receptor kinase-like proteins are required for meristem function in Arabidopsis

Authors

  • Brody J. DeYoung,

    1. Department of Molecular, Cellular and Developmental Biology, University of Michigan, 830 North University, Ann Arbor, MI 48109-1048, USA,
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  • Kristen L. Bickle,

    1. Department of Molecular, Cellular and Developmental Biology, University of Michigan, 830 North University, Ann Arbor, MI 48109-1048, USA,
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  • Katherine J. Schrage,

    1. Department of Molecular, Cellular and Developmental Biology, University of Michigan, 830 North University, Ann Arbor, MI 48109-1048, USA,
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  • Paul Muskett,

    1. The Sainsbury Laboratory, John Innes Centre, Norwich NR4 7UH, UK, and
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    • Present address: Department of Plant-Microbe Interactions, Max-Planck-Institute for Plant Breeding Research, Carl von Linne Weg 10, D-50829, Cologne, Germany.

  • Kanu Patel,

    1. Disease and Stress Biology, John Innes Centre, Norwich NR4 7UH, UK
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    • Present address: Ringsjöhöjden, Storvägen 4, 243 35 HÖÖR, Sweden.

  • Steven E. Clark

    Corresponding author
    1. Department of Molecular, Cellular and Developmental Biology, University of Michigan, 830 North University, Ann Arbor, MI 48109-1048, USA,
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Summary

Organ formation at shoot and flower meristems in plants requires the maintenance of a population of centrally located stem cells and the differentiation of peripherally located daughter cells. The CLAVATA (CLV) gene products in Arabidopsis, including the CLV1 receptor-kinase, regulate this process by promoting the differentiation of stem cells on the meristem flanks. Here, we have analyzed the developmental roles of the CLV1-related BAM1 (derived from barely any meristem 1), BAM2 and BAM3 receptor-like kinases. Loss-of-function alleles of these receptors lead to phenotypes consistent with the loss of stem cells at the shoot and flower meristem, suggesting that their developmental role is opposite to that of CLV1. These closely related receptors are further distinguished from CLV1, whose expression and function is highly specific, by having broad expression patterns and multiple developmental roles. These include a requirement for BAM1, BAM2 and BAM3 in the development of high-ordered vascular strands within the leaf and a correlated control of leaf shape, size and symmetry. In addition, BAM1, BAM2 and BAM3 are required for male gametophyte development, as well as ovule specification and function. Significantly, the differing roles of CLV1 and BAM receptors in meristem and organ development are largely driven by differences in expression patterns.

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