title: Organ regeneration does not require a functional stem cell niche in plants.
abstract: Plants rely on the maintenance of stem cell niches at their apices for the continuous growth of roots and shoots. However, although the developmental plasticity of plant cells has been demonstrated, it is not known whether the stem cell niche is required for organogenesis. Here we explore the capacity of a broad range of differentiating cells to regenerate an organ without the activity of a stem cell niche. Using a root-tip regeneration system in Arabidopsis thaliana to track the molecular and functional recovery of cell fates, we show that re-specification of lost cell identities begins within hours of excision and that the function of specialized cells is restored within one day. Critically, regeneration proceeds in plants with mutations that fail to maintain the stem cell niche. These results show that stem-cell-like properties that mediate complete organ regeneration are dispersed in plant meristems and are not restricted to niches, which nonetheless seem to be necessary for indeterminate growth. This regenerative reprogramming of an entire organ without transition to a stereotypical stem cell environment has intriguing parallels to recent reports of induced transdifferentiation of specific cell types in the adult organs of animals.
authors.affiliation: New York University, Department of Biology, Center for Genomics and Systems Biology, Silver Building, 100 Washington Square East, New York, New York 10003, USA.
authors.forename: Giovanni
authors.initials: G
authors.lastname: Sena
authors.forename: Xiaoning
authors.initials: X
authors.lastname: Wang
authors.forename: Hsiao-Yun
authors.initials: HY
authors.lastname: Liu
authors.forename: Hugo
authors.initials: H
authors.lastname: Hofhuis
authors.forename: Kenneth D
authors.initials: KD
authors.lastname: Birnbaum
mesh_terms: D017360:Arabidopsis / Q000166:cytology / Q000254:growth & development*; D015415:Biomarkers / Q000032:analysis; D019070:Cell Lineage; D054338:Cell Transdifferentiation; D007210:Indoleacetic Acids / Q000378:metabolism; D020411:Oligonucleotide Array Sequence Analysis; D038081:Organogenesis; D018517:Plant Roots / Q000166:cytology / Q000254:growth & development; D012038:Regeneration / Q000502:physiology*; D013213:Starch / Q000032:analysis / Q000378:metabolism; D055153:Stem Cell Niche / Q000502:physiology; D013234:Stem Cells / Q000166:cytology / Q000378:metabolism
chemical_list: D015415:Biomarkers; D007210:Indoleacetic Acids; D013213:Starch