The peri-cell-cycle in Arabidopsis

Beeckman, Tom; Burssens, Sylvia; Inzé, Dirk

doi:10.1093/jexbot/52.suppl_1.403

Cited by 178 publications

(116 citation statements)

References 18 publications

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“…Furthermore, our results reveal an emerging distal 'meristematic' region with small cells-and a proximal region where cell expansion prevails-caused by different levels of auxin within the self-generated auxin profile. Also in line with experimental data 36 , mitotic activity in vascular regions extends further up (Fig. 5e) than in peripheral regions.…”

Section: Emergence and Dynamics Of Zonation In Growing Rootssupporting

confidence: 90%

Auxin transport is sufficient to generate a maximum and gradient guiding root growth

Grieneisen¹,

Marée³

et al. 2007

Nature

755

852

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The plant growth regulator auxin controls cell identity, cell division and cell expansion. Auxin efflux facilitators (PINs) are associated with auxin maxima in distal regions of both shoots and roots. Here we model diffusion and PIN-facilitated auxin transport in and across cells within a structured root layout. In our model, the stable accumulation of auxin in a distal maximum emerges from the auxin flux pattern. We have experimentally tested model predictions of robustness and self-organization. Our model explains pattern formation and morphogenesis at timescales from seconds to weeks, and can be understood by conceptualizing the root as an 'auxin capacitor'. A robust auxin gradient associated with the maximum, in combination with separable roles of auxin in cell division and cell expansion, is able to explain the formation, maintenance and growth of sharply bounded meristematic and elongation zones. Directional permeability and diffusion can fully account for stable auxin maxima and gradients that can instruct morphogenesis.

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Section: Emergence and Dynamics Of Zonation In Growing Rootssupporting

confidence: 90%

Auxin transport is sufficient to generate a maximum and gradient guiding root growth

Grieneisen¹,

Marée³

et al. 2007

Nature

755

852

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show abstract

“…We used the CYCB1:uidA promoter fusion as a reporter gene to monitor lateral root formation. Indeed, CYCB1 is one of the earliest genes expressed in the pericycle cells that will develop into a lateral root (Beeckman et al, 2001). As shown in Figures 3A to 3D, ago1-3 was able to initiate and develop lateral roots in response to 1 mM 1-NAA in a similar way to the wild type.…”

Section: Ago1-3 Is Altered In Adventitious Root Formation But Not In mentioning

confidence: 73%

Auxin and Light Control of Adventitious Rooting in Arabidopsis Require ARGONAUTE1

et al. 2005

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Adventitious rooting is a quantitative genetic trait regulated by both environmental and endogenous factors. To better understand the physiological and molecular basis of adventitious rooting, we took advantage of two classes of Arabidopsis thaliana mutants altered in adventitious root formation: the superroot mutants, which spontaneously make adventitious roots, and the argonaute1 (ago1) mutants, which unlike superroot are barely able to form adventitious roots. The defect in adventitious rooting observed in ago1 correlated with light hypersensitivity and the deregulation of auxin homeostasis specifically in the apical part of the seedlings. In particular, a clear reduction in endogenous levels of free indoleacetic acid (IAA) and IAA conjugates was shown. This was correlated with a downregulation of the expression of several auxininducible GH3 genes in the hypocotyl of the ago1-3 mutant. We also found that the Auxin Response Factor17 (ARF17) gene, a potential repressor of auxin-inducible genes, was overexpressed in ago1-3 hypocotyls. The characterization of an ARF17-overexpressing line showed that it produced fewer adventitious roots than the wild type and retained a lower expression of GH3 genes. Thus, we suggest that ARF17 negatively regulates adventitious root formation in ago1 mutants by repressing GH3 genes and therefore perturbing auxin homeostasis in a light-dependent manner. These results suggest that ARF17 could be a major regulator of adventitious rooting in Arabidopsis.

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“…Root formation is a model system in which to study the relationship between these two auxin pathways. Root primordia form by orchestrated cell division of three competent cells in the subtending pericycle, and the root emerges from its associated ground tissue by elongation (Malamy and Benfey, 1997;Beeckman et al, 2001;Dubrovsky et al, 2001). In root formation, both cell division and elongation are controlled strictly by auxin.…”

Section: Discussionmentioning

confidence: 99%

The β-Subunit of the Arabidopsis G Protein Negatively Regulates Auxin-Induced Cell Division and Affects Multiple Developmental Processes[W]

et al. 2003

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Plant cells respond to low concentrations of auxin by cell expansion, and at a slightly higher concentration, these cells divide. Previous work revealed that null mutants of the ␣ -subunit of a putative heterotrimeric G protein ( GPA1 ) have reduced cell division. Here, we show that this prototypical G protein complex acts mechanistically by controlling auxin sensitivity toward cell division. Loss-of-function G protein mutants have altered auxin-mediated cell division throughout development, especially during the auxin-induced formation of lateral and adventitious root primordia. Ectopic expression of the wild-type G ␣ -subunit phenocopies the G ␤ mutants (auxin hypersensitivity), probably by sequestering the G ␤␥ -subunits, whereas overexpression of G ␤ reduces auxin sensitivity and a constitutively active (Q222L) mutant G ␣ behaves like the wild type. These data are consistent with a model in which G ␤␥ acts as a negative regulator of auxin-induced cell division. Accordingly, basal repression of approximately one-third of the identified auxin-regulated genes (47 of 150 upregulated genes among 8300 quantitated) is lost in the G ␤ transcript-null mutant. Included among these are genes that encode proteins proposed to control cell division in root primordia formation as well as several novel genes. These results suggest that although auxin-regulated cell division is not coupled directly by a G protein, the G ␤ -subunit attenuates this auxin pathway upstream of the control of mRNA steady state levels.

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The peri-cell-cycle in Arabidopsis

Cited by 178 publications

References 18 publications

Auxin transport is sufficient to generate a maximum and gradient guiding root growth

Auxin transport is sufficient to generate a maximum and gradient guiding root growth

Auxin and Light Control of Adventitious Rooting in Arabidopsis Require ARGONAUTE1

The β-Subunit of the Arabidopsis G Protein Negatively Regulates Auxin-Induced Cell Division and Affects Multiple Developmental Processes[W]

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