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, while the developmental plasticity of plant cells has been demonstrated1, 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 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 appear 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 animals2,3.

Externally imposed electric field enhances plant root tip regeneration

“…Note that all these cuts resulted in the complete removal of the root apical stem cell niche, as previously described (Sena et al. 2009). …”

“…2009). This generated temporal series of median optical sections, conveying information on the dynamics of the process for individual roots that did successfully regenerate, after 30‐min electric field exposure or mock conditions.…”

“…2006) or their whole apices in planta without the requirement of any exogenous phytohormone (Feldman 1976; Francis 1978; Rost & Jones 1988; Sena et al. 2009). When grown on the surface of solid medium plates, Arabidopsis root apices regenerate with a probability that quickly decreases with the distance of the excision point from the apex (Rost & Jones 1988; Sena et al.…”

“…When grown on the surface of solid medium plates, Arabidopsis root apices regenerate with a probability that quickly decreases with the distance of the excision point from the apex (Rost & Jones 1988; Sena et al. 2009). This defines a spatial gradient of regeneration competence, whose establishment and maintenance remains poorly understood to date.…”

“…Remarkably, the regeneration of fully excised root apices occurs even in Arabidopsis mutants with impaired apical stem cell niches (Sena et al. 2009). …”