@article{12b176dfef89482fbaa3ffd5b2f3a3f6,
title = "An evolutionarily conserved NIMA-related kinase directs rhizoid tip growth in the basal land plant Marchantia polymorpha",
abstract = "Tip growth is driven by turgor pressure and mediated by the polarized accumulation of cellular materials. How a single polarized growth site is established and maintained is unclear. Here, we analyzed the function of NIMA-related protein kinase 1 (MpNEK1) in the liverwort Marchantia polymorpha. In the wild type, rhizoid cells differentiate from the ventral epidermis and elongate through tip growth to form hair-like protrusions. In Mpnek1 knockout mutants, rhizoids underwent frequent changes in growth direction, resulting in a twisted and/or spiral morphology. The functional MpNEK1-Citrine protein fusion localized to microtubule foci in the apical growing region of rhizoids. Mpnek1 knockouts exhibited increases in both microtubule density and bundling in the apical dome of rhizoids. Treatment with the microtubule-stabilizing drug taxol phenocopied the Mpnek1 knockout. These results suggest that MpNEK1 directs tip growth in rhizoids through microtubule organization. Furthermore, MpNEK1 expression rescued ectopic outgrowth of epidermal cells in the Arabidopsis thaliana nek6 mutant, strongly supporting an evolutionarily conserved NEK-dependent mechanism of directional growth. It is possible that such a mechanism contributed to the evolution of the early rooting system in land plants.",
keywords = "Cell polarity, Marchantia polymorpha, NIMA-related kinase, Rhizoid, Tip growth",
author = "Kento Otani and Kimitsune Ishizaki and Ryuichi Nishihama and Shogo Takatani and Takayuki Kohchi and Taku Takahashi and Hiroyasu Motose",
note = "Funding Information: This work was supported by the Grants-in-Aid from the Ministry of Education, Culture, Sports, Science and Technology, Japan (KAKENHI grant numbers 23119513, 25113009, 25119715, 25440137, 16K07403, 16H01245), the Ryobi Teien Memory Foundation, the NOVARTIS Foundation (Japan) for the Promotion of Science, and Nakahara Education and Research Support Fund in Okayama University. S.T. was supported by a Grant-in-Aid for Japan Society for the Promotion of Science Research Fellow (KAKENHI grant number 16J03501). Funding Information: We thank Sakiko Ishida (Kyoto University) for assistance with gene targeting; Shigeyuki Tsukamoto (Kobe University) for technical assistance with transformation; Professor Tsuyoshi Nakagawa (Shimane University) for pGWB550; Professor Takashi Ueda, Dr Atsuko Era, Dr Kazuo Ebine and Dr Takehiko Kanazawa (NIBB) for pENTR-Lifeact-Venus and advice on plasmid construction; Dr Olivier Hamant (ENSLyon) for the Arabidopsis CaMV35Spro:GFP-MBD line; Dr David N. Drechsel (Max Planck Institute) for pGEX-6P-1-Stu2; Dr Takashi Hotta and Professor Takashi Hashimoto (NAIST) for technical assistance with tubulin purification; Professor Yuichiro Takahashi (Okayama University) for use of FLA-7000; and Professor Mitsuyasu Hasebe (NIBB) for the Physcomitrella NIBB-David strain. Publisher Copyright: {\textcopyright} 2018. Published by The Company of Biologists Ltd.",
year = "2018",
month = mar,
doi = "10.1242/dev.154617",
language = "English",
volume = "145",
journal = "Journal of Embryology and Experimental Morphology",
issn = "0950-1991",
publisher = "Company of Biologists Ltd",
number = "5",
}