Publication

Journal	New Phytologist
Page(s)	nph.16276 - nph.16276
Title of proceedings	New Phytologist
DOI	10.1111/nph.16276

URL	http://doi.org/10.1111/nph.16276
Type of Open Access	Publisher (Gold Open Access)

During land colonization, plants acquired a range of body plan adaptations, of which the innovation of three-dimensional (3D) tissues increased organismal complexity and reproduc- tivity. In the moss, Physcomitrella patens, a 3D leafy gametophore originates from filamen- tous cells that grow in a two-dimensional (2D) plane through a series of asymmetric cell divisions. Asymmetric cell divisions that coincide with different cell division planes and growth directions enable the developmental switch from 2D to 3D, but insights into the underlying mechanisms coordinating this switch are still incomplete. Using 2D and 3D imaging and image segmentation, we characterized two geometric cues, the width of the initial cell and the angle of the transition division plane, which sufficiently dis- tinguished a gametophore initial cell from a branch initial cell. These identified cues were fur- ther confirmed in gametophore formation mutants. The identification of a fluorescent marker allowed us to successfully predict the game- tophore initial cell with >90% accuracy before morphological changes, supporting our hypothesis that, before the transition division, parental cells of the gametophore initials pos- sess different properties from those of the branch initials. Our results suggest that the cell fate decision of the initial cell is determined in the parental cell, before the transition division.