Development and Cell Cycle Activity of the Root Apical Meristem in the Fern Ceratopteris richardii

Abstract
Ferns are a representative clade in plant evolution although underestimated in the genomic era. Ceratopteris richardii is an emergent model for developmental processes in ferns, yet a complete scheme of the different growth stages is necessary. Here, we present a developmental analysis, at the tissue and cellular levels, of the first shoot-borne root of Ceratopteris. We followed early stages and emergence of the root meristem in sporelings. While assessing root growth, the first shoot-borne root ceases its elongation between the emergence of the fifth and sixth roots, suggesting Ceratopteris roots follow a determinate developmental program. We report cell division frequencies in the stem cell niche after detecting labeled nuclei in the root apical cell (RAC) and derivatives after 8 h of exposure. These results demonstrate the RAC has a continuous mitotic activity during root development. Detection of cell cycle activity in the RAC at early times suggests this cell acts as a non-quiescent organizing center. Overall, our results provide a framework to study root function and development in ferns and to better understand the evolutionary history of this organ.

Citation
Aragón-Raygoza, A., Vasco, A., Blilou, I., Herrera-Estrella, L., & Cruz-Ramírez, A. (2020). Development and Cell Cycle Activity of the Root Apical Meristem in the Fern Ceratopteris richardii. Genes, 11(12), 1455. doi:10.3390/genes11121455

Acknowledgements
This research received no external funding. A.A.-R. was financially supported by a CONACyT PhD Fellowship (No. 421596). We thank Jane Langdale and Andrew Plackett (Oxford University), and Pamela Soltis, Doug Soltis and Blaine Marchant (University of Florida), for providing us with Ceratopteris richardii Hn-n spores. To our lab manager Annie Espinal-Centeno for obtaining the first batch of Ceratopteris spores to begin with this project.

Publisher
MDPI AG

Journal
Genes

DOI
10.3390/genes11121455
10.1101/2020.08.27.271049

PubMed ID
33291610

Additional Links
https://www.mdpi.com/2073-4425/11/12/1455http://biorxiv.org/lookup/doi/10.1101/2020.08.27.271049

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