scholarly journals Lateral root initiation is a probabilistic event whose frequency is set by fluctuating levels of auxin response

2013 ◽  
Vol 64 (9) ◽  
pp. 2609-2617 ◽  
Author(s):  
Marta Laskowski
Keyword(s):  
Lateral Root ◽  
Root Initiation ◽  
Auxin Response ◽  
Lateral Root Initiation

scholarly journals GNOM/FEWER ROOTS is Required for the Establishment of an Auxin Response Maximum for Arabidopsis Lateral Root Initiation

2013 ◽  
Vol 54 (3) ◽  
pp. 406-417 ◽  
Author(s):  
Ken-ichi Okumura ◽  
Tatsuaki Goh ◽  
Koichi Toyokura ◽  
Hiroyuki Kasahara ◽  
Yumiko Takebayashi ◽  
...  
Keyword(s):  
Lateral Root ◽  
Root Initiation ◽  
Auxin Response ◽  
Lateral Root Initiation

scholarly journals Phloem-associated auxin response maxima determine radial positioning of lateral roots in maize

2012 ◽  
Vol 367 (1595) ◽  
pp. 1525-1533 ◽  
Author(s):  
Leentje Jansen ◽  
Ianto Roberts ◽  
Riet De Rycke ◽  
Tom Beeckman
Keyword(s):  
Lateral Root ◽  
Vascular Tissue ◽  
Lateral Roots ◽  
Root Tip ◽  
Root Initiation ◽  
Auxin Response ◽  
Lateral Root Initiation ◽  
Evolutionarily Conserved ◽  
Chemical Inhibition ◽  
Pericycle Cells

In Arabidopsis thaliana , lateral-root-forming competence of pericycle cells is associated with their position at the xylem poles and depends on the establishment of protoxylem-localized auxin response maxima. In maize, our histological analyses revealed an interruption of the pericycle at the xylem poles, and confirmed the earlier reported proto-phloem-specific lateral root initiation. Phloem-pole pericycle cells were larger and had thinner cell walls compared with the other pericycle cells, highlighting the heterogeneous character of the maize root pericycle. A maize DR5::RFP marker line demonstrated the presence of auxin response maxima in differentiating xylem cells at the root tip and in cells surrounding the proto-phloem vessels. Chemical inhibition of auxin transport indicated that the establishment of the phloem-localized auxin response maxima is crucial for lateral root formation in maize, because in their absence, random divisions of pericycle and endodermis cells occurred, not resulting in organogenesis. These data hint at an evolutionarily conserved mechanism, in which the establishment of vascular auxin response maxima is required to trigger cells in the flanking outer tissue layer for lateral root initiation. It further indicates that lateral root initiation is not dependent on cellular specification or differentiation of the type of vascular tissue.

Formation of lateral root meristems is a two-stage process

Development ◽  
1995 ◽  
Vol 121 (10) ◽  
pp. 3303-3310 ◽  
Author(s):  
M.J. Laskowski ◽  
M.E. Williams ◽  
H.C. Nusbaum ◽  
I.M. Sussex
Keyword(s):  
Lateral Root ◽  
Lateral Roots ◽  
Initial Period ◽  
Subsequent Stage ◽  
Root Initiation ◽  
Root Meristems ◽  
Lateral Root Initiation ◽  
Cell Layers ◽  
Stage Process ◽  
Pericycle Cells

In both radish and Arabidopsis, lateral root initiation involves a series of rapid divisions in pericycle cells located on the xylem radius of the root. In Arabidopsis, the number of pericycle cells that divide to form a primordium was estimated to be about 11. To determine the stage at which primordia are able to function as root meristems, primordia of different stages were excised and cultured without added hormones. Under these conditions, primordia that consist of 2 cell layers fail to develop while primordia that consist of at least 3–5 cell layers develop as lateral roots. We hypothesize that meristem formation is a two-step process involving an initial period during which a population of rapidly dividing, approximately isodiametric cells that constitutes the primordium is formed, and a subsequent stage during which meristem organization takes place within the primordium.

scholarly journals Interacting Glutamate Receptor-Like Proteins in Phloem Regulate Lateral Root Initiation in Arabidopsis

2013 ◽  
Vol 25 (4) ◽  
pp. 1304-1313 ◽  
Author(s):  
Eric D. Vincill ◽  
Arielle E. Clarin ◽  
Jennifer N. Molenda ◽  
Edgar P. Spalding
Keyword(s):  
Glutamate Receptor ◽  
Lateral Root ◽  
Root Initiation ◽  
Lateral Root Initiation

scholarly journals Auxin minimum defines a developmental window for lateral root initiation

2011 ◽  
Vol 191 (4) ◽  
pp. 970-983 ◽  
Author(s):  
Joseph G. Dubrovsky ◽  
Selene Napsucialy-Mendivil ◽  
Jérme Duclercq ◽  
Yan Cheng ◽  
Svetlana Shishkova ◽  
...  
Keyword(s):  
Lateral Root ◽  
Root Initiation ◽  
Lateral Root Initiation ◽  
Developmental Window

scholarly journals AT-HOOK MOTIF NUCLEAR LOCALISED PROTEIN 18 as a Novel Modulator of Root System Architecture

2020 ◽  
Author(s):  
Marek Šírl ◽  
Tereza Šnajdrová ◽  
Dolores Gutiérrez-Alanís ◽  
Joseph G. Dubrovsky ◽  
Jean Phillipe Vielle-Calzada ◽  
...  
Keyword(s):  
Root System ◽  
System Architecture ◽  
Lateral Root ◽  
Apical Meristem ◽  
Lateral Roots ◽  
Primary Root ◽  
Root System Architecture ◽  
Root Apical Meristem ◽  
Root Initiation ◽  
Lateral Root Initiation

The AT-HOOK MOTIF NUCLEAR LOCALIZED PROTEIN (AHL) gene family encodes embryophyte-specific nuclear proteins with DNA binding activity. They modulate gene expression and affect various developmental processes in plants. We identify AHL18 (At3G60870) as a developmental modulator of root system architecture and growth. AHL18 regulates the length of the proliferation domain and number of dividing cells in the root apical meristem and thereby, cell production. Both primary root growth and lateral root development respond according to AHL18 transcription level. The ahl18 knock-out plants show reduced root systems due to a shorter primary root and a lower number of lateral roots. This change results from a higher number of arrested and non-developing lateral root primordia (LRP) rather than from decreased initiation. Overexpression of AHL18 results in a more extensive root system, longer primary roots, and increased density of lateral root initiation events. Formation of lateral roots is affected during the initiation of LRP and later development. AHL18 regulate root apical meristem activity, lateral root initiation and emergence, which is in accord with localization of its expression.

scholarly journals The lateral root initiation index: an integrative measure of primordium formation

2009 ◽  
Vol 103 (5) ◽  
pp. 807-817 ◽  
Author(s):  
J. G. Dubrovsky ◽  
A. Soukup ◽  
S. Napsucialy-Mendivil ◽  
Z. Jeknić ◽  
M. G. Ivanchenko
Keyword(s):  
Lateral Root ◽  
Root Initiation ◽  
Lateral Root Initiation

Lateral root initiation in Marsilea quadrifolia. I. Origin and histogenesis of lateral roots

1991 ◽  
Vol 69 (1) ◽  
pp. 123-135 ◽  
Author(s):  
Bai-Ling Lin ◽  
V. Raghavan
Keyword(s):  
Lateral Root ◽  
Single Cells ◽  
Lateral Roots ◽  
Central Axis ◽  
Root Initiation ◽  
Vascular Connection ◽  
Lateral Root Initiation ◽  
Marsilea Quadrifolia ◽  
Lateral Root Primordium ◽  
Root Primordium

In Marsilea quadrifolia, lateral roots arise from modified single cells of the endodermis located opposite the protoxylem poles within the meristematic region of the parent root. The initial cell divides in four specific planes to establish a fivecelled lateral root primordium, with a tetrahedral apical cell in the centre and the oldest merophytes and the root cap along the sides. The cells of the merophyte divide in a precise pattern to give rise to the cells of the cortex, endodermis, pericycle, and vascular tissues of the emerging lateral root. Although the construction of the parent root is more complicated than that of lateral roots, patterns of cell division and tissue formation are similar in both types of roots, with the various tissues being arranged in similar positions in relation to the central axis. Vascular connection between the lateral root primordium and the parent root is derived from the pericycle cells lying between the former and the protoxylem members of the latter. It is proposed that the central axis of the root is not only a geometric centre, but also a physiological centre which determines the fate of the different cell types. Key words: lateral root initiation, Marsilea quadrifolia, root histogenesis.

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