A Self-Organized PLT/Auxin/ARR-B Network Controls the Dynamics of Root Zonation Development in Arabidopsis thaliana

Abstract

Highlights d Upon germination, cell divisions generate a PLT drop that forms the transition zone d A PLTs-ARR12 mutual antagonism restricts early root meristem expansion d ARR1 repression of cell division via KRP2 is key for meristem size stabilization

Integrative Roles of Phytohormones on Cell Proliferation, Elongation and Differentiation in the Arabidopsis thaliana Primary Root

“…As mentioned above, the MZ consists of two different domains: the proliferation domain (PD) and the transition domain (TD) (Verbelen et al, 2006;Ivanov and Dubrovsky, 2013;Salvi et al, 2020; Figure 1).…”

“…The CK and auxin crosstalk is well described, and it is known to regulate the MZ size by controlling the transition from proliferation to elongation (Salvi et al, 2020). CK interferes with auxin responses and transport in the MZ as follow: SHY2/IAA3 is positively regulated by ARR1 and is sufficient to mediate ARR1 function in the MZ size, because the OE of ARR1 in the LoF mutant shy2-31, does not show a MZ reduction.…”

“…The cell cycle of the transition domain (TD) cells is changing from cell division to endoreduplication, in which cells undergo several cycles of DNA replication with no cytokinesis (Verbelen et al, 2006;Bhosale et al, 2018;Salvi et al, 2020; Figure 3A). Moreover, these cells continue to grow at the same rate as in the PD but the frequency of division decreases resulting in the coexistence of cells that may still divide with others that undergo endoreduplication and are relatively larger than those in the PD (Ivanov and Dubrovsky, 2013).…”

“…Roots are an excellent model to study the balance between cell division, elongation and differentiation as these processes are spatially separated along the main axis (Scheres and Wolkenfelt, 1998). The organization from the tip of the root to the base of the stem consists of different tissues and zones, starting with the columella, which confers soil abrasion resistance, followed by the MZ, the Elongation Zone (EZ) and the Differentiation Zone (DZ) (Figure 1; Baluška et al, 1996;Verbelen et al, 2006;Ivanov and Dubrovsky, 2013;Salvi et al, 2020). The MZ is the region within the root where cells are produced, and it consists of the Stem Cell Niche (SCN), the Proliferation Domain (PD) and the Transition Domain (TD) (Baluška et al, 1994(Baluška et al, , 2010Verbelen et al, 2006;Ivanov and Dubrovsky, 2013;Salvi et al, 2020; Figure 1).…”

“…The organization from the tip of the root to the base of the stem consists of different tissues and zones, starting with the columella, which confers soil abrasion resistance, followed by the MZ, the Elongation Zone (EZ) and the Differentiation Zone (DZ) (Figure 1; Baluška et al, 1996;Verbelen et al, 2006;Ivanov and Dubrovsky, 2013;Salvi et al, 2020). The MZ is the region within the root where cells are produced, and it consists of the Stem Cell Niche (SCN), the Proliferation Domain (PD) and the Transition Domain (TD) (Baluška et al, 1994(Baluška et al, , 2010Verbelen et al, 2006;Ivanov and Dubrovsky, 2013;Salvi et al, 2020; Figure 1). The SCN has a central organizer known as the Quiescent Center (QC) surrounded by stem cells that divide to self-renew and to provide cells that will populate either the PD or the columella, in the case of the distal stem cells (Dolan et al, 1993;Van den Berg et al, 1995;Van Den Berg et al, 1997;Benfey and Scheres, 2000; Figure 1).…”