BAM1/2 receptor kinase signaling drives CLE peptide-mediated formative cell divisions in Arabidopsis roots

Ashley D. Crook, Andrew C. Willoughby, Ora Hazak, Satohiro Okuda, Kylie R. VanDerMolen, Cara L. Soyars, Pietro Cattaneo, Natalie M. Clark, Rosangela Sozzani, Michael Hothorn, Christian S. Hardtke, Zachary L. Nimchuk
2020 Proceedings of the National Academy of Sciences of the United States of America  
Cell division is often regulated by extracellular signaling networks to ensure correct patterning during development. In Arabidopsis, the SHORT-ROOT (SHR)/SCARECROW (SCR) transcription factor dimer activates CYCLIND6;1 (CYCD6;1) to drive formative divisions during root ground tissue development. Here, we show plasma-membrane-localized BARELY ANY MERISTEM1/2 (BAM1/2) family receptor kinases are required for SHR-dependent formative divisions and CYCD6;1 expression, but not SHR-dependent ground
more » ... dependent ground tissue specification. Root-enriched CLE ligands bind the BAM1 extracellular domain and are necessary and sufficient to activate SHR-mediated divisions and CYCD6;1 expression. Correspondingly, BAM-CLE signaling contributes to the restriction of formative divisions to the distal root region. Additionally, genetic analysis reveals that BAM-CLE and SHR converge to regulate additional cell divisions outside of the ground tissues. Our work identifies an extracellular signaling pathway regulating formative root divisions and provides a framework to explore this pathway in patterning and evolution.
doi:10.1073/pnas.2018565117 pmid:33288706 fatcat:egqvnyaf5bcrni4e45qf4fwapm