Length and activity of the root apical meristem revealed in vivo by infrared imaging

Bizet, François; Hummel, Irène; Bogeat‐Triboulot, Marie‐Béatrice

doi:10.1093/jxb/eru488

Cited by 29 publications

(60 citation statements)

References 46 publications

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“…S6). During root growth individual cells arise sequentially as progeny from the SCN [Bizet et al, 2015], and while moving through the MZ they give rise to expanding clones of sibling cells exhibiting approximately synchronous growth and division dynamics [von Wangenheim et al, 2017]. Due to the position based transition from the MZ to the TZ and EZ, these sibling cells sequentially leave the meristem.…”

Section: Discussionmentioning

confidence: 99%

Lateral Root Priming Synergystically Arises from Root Growth and Auxin Transport Dynamics

2018

Preprint

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The root system is a major determinant of plant fitness. Its capacity to supply the plant with sufficient water and nutrients strongly depends on root system architecture, which arises from the repeated branching off of lateral roots. A critical first step in lateral root formation is priming, which prepatterns sites competent of forming a lateral root. Priming is characterized by temporal oscillations in auxin, auxin signalling and gene expression in the root meristem, which through growth become transformed into a spatially repetitive pattern of competent sites. Previous studies have demonstrated the importance of auxin synthesis, transport and perception for the amplitude of these oscillations and their chances of producing an actual competent site. Additionally, repeated lateral root cap apoptosis was demonstrated to be strongly correlated with repetitive lateral root priming. Intriguingly, no single mutation has been identified that fully abolishes lateral root formation, and thusfar the mechanism underlying oscillations has remained unknown. In this study, we investigated the impact of auxin reflux loop properties combined with root growth dynamics on priming, using a computational approach. To this end we developed a novel multi-scale root model incorporating a realistic root tip architecture and reflux loop properties as well as root growth dynamics. Excitingly, in this model, repetitive auxin elevations automatically emerge. First, we show that root tip architecture and reflux loop properties result in an auxin loading zone at the start of the elongation zone, with preferential auxin loading in narrow vasculature cells. Second, we demonstrate how meristematic root growth dynamics causes regular alternations in the sizes of cells arriving at the elongation zone, which subsequently become amplified during cell expansion. These cell size differences translate into differences in cellular auxin loading potential. Combined, these properties result in temporal and spatial fluctuations in auxin levels in vasculature and pericycle cells. Our model predicts that temporal priming frequency predominantly depends on cell cycle duration, while cell cycle duration together with meristem size control lateral root spacing.

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Section: Discussionmentioning

confidence: 99%

Lateral Root Priming Synergystically Arises from Root Growth and Auxin Transport Dynamics

2018

Preprint

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“…Sensitivity of cell elongation to water deficit has been shown in several species using kinematics (Sharp et al , 1988; Triboulot et al , 1995). The importance of apical meristem activity in determining growth rate has been highlighted (Beemster and Baskin, 1998), and its sensitivity to water deficit has been shown in maize and poplar roots (Fraser et al , 1990; Sacks et al , 1997; Bizet et al , 2015 b ). The balance between proliferation and elongation processes, as well as their underlying molecular control, is a current research focus (Tardieu et al , 2011; Baskin, 2013; De Vos et al , 2014).…”

Section: Introductionmentioning

confidence: 99%

The build-up of osmotic stress responses within the growing root apex using kinematics and RNA-sequencing

Royer

Cohen

Aubry

et al. 2016

EXBOTJ

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“…2a), resembling that of untreated roots (Fig. 2a; [13]). It appears, therefore, that meristematic cell expansion ceased concomitantly with the aphidicolin-induced cell cycle arrest, resulting in cortical microtubule reorientation.…”

Section: Resultsmentioning

confidence: 74%

Cortical microtubule orientation in Arabidopsis thaliana root meristematic zone depends on cell division and requires severing by katanin

Panteris

Diannelidis

Adamakis

2018

J of Biol Res-Thessaloniki

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BackgroundTransverse cortical microtubule orientation, critical for anisotropic cell expansion, is established in the meristematic root zone. Intending to elucidate the possible prerequisites for this establishment and factors that are involved, microtubule organization was studied in roots of Arabidopsis thaliana, wild-type and the p60-katanin mutants fra2, ktn1-2 and lue1. Transverse cortical microtubule orientation in the meristematic root zone has proven to persist under several regimes inhibiting root elongation. This persistence was attributed to the constant moderate elongation of meristematic cells, prior to mitotic division. Therefore, A. thaliana wild-type seedlings were treated with aphidicolin, in order to prevent mitosis and inhibit premitotic cell elongation.ResultsIn roots treated with aphidicolin for 12 h, cell divisions still occurred and microtubules were transverse. After 24 and 48 h of treatment, meristematic cell divisions and the prerequisite elongation ceased, while microtubule orientation became random. In meristematic cells of the p60-katanin mutants, apart from a general transverse microtubule pattern, cortical microtubules with random orientation were observed, also converging at several cortical sites, in contrast to the uniform transverse pattern of wild-type cells.ConclusionTaken together, these observations reveal that transverse cortical microtubule orientation in the meristematic zone of A. thaliana root is cell division-dependent and requires severing by katanin.

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Length and activity of the root apical meristem revealed in vivo by infrared imaging

Abstract: SummaryA fast and in vivo approach to assess the dynamics of root apical meristem length.

Cited by 29 publications

References 46 publications

Lateral Root Priming Synergystically Arises from Root Growth and Auxin Transport Dynamics

Lateral Root Priming Synergystically Arises from Root Growth and Auxin Transport Dynamics

The build-up of osmotic stress responses within the growing root apex using kinematics and RNA-sequencing

Cortical microtubule orientation in Arabidopsis thaliana root meristematic zone depends on cell division and requires severing by katanin

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