scholarly journals Interplay of Auxin and Cytokinin in Lateral Root Development

2019 ◽  
Vol 20 (3) ◽  
pp. 486 ◽  
Author(s):  
Hongwei Jing ◽  
Lucia Strader

The spacing and distribution of lateral roots are critical determinants of plant root system architecture. In addition to providing anchorage, lateral roots explore the soil to acquire water and nutrients. Over the past several decades, we have deepened our understanding of the regulatory mechanisms governing lateral root formation and development. In this review, we summarize these recent advances and provide an overview of how auxin and cytokinin coordinate the regulation of lateral root formation and development.

2021 ◽  
Author(s):  
Pierre-Mathieu Pélissier ◽  
Hans Motte ◽  
Tom Beeckman

Abstract Lateral roots are important to forage for nutrients due to their ability to increase the uptake area of a root system. Hence, it comes as no surprise that lateral root formation is affected by nutrients or nutrient starvation, and as such contributes to the root system plasticity. Understanding the molecular mechanisms regulating root adaptation dynamics towards nutrient availability is useful to optimize plant nutrient use efficiency. There is at present a profound, though still evolving, knowledge on lateral root pathways. Here, we aimed to review the intersection with nutrient signaling pathways to give an update on the regulation of lateral root development by nutrients, with a particular focus on nitrogen. Remarkably, it is for most nutrients not clear how lateral root formation is controlled. Only for nitrogen, one of the most dominant nutrients in the control of lateral root formation, the crosstalk with multiple key signals determining lateral root development is clearly shown. In this update, we first present a general overview of the current knowledge of how nutrients affect lateral root formation, followed by a deeper discussion on how nitrogen signaling pathways act on different lateral root-mediating mechanisms for which multiple recent studies yield insights.


Plants ◽  
2019 ◽  
Vol 8 (4) ◽  
pp. 103 ◽  
Author(s):  
Wei Dong ◽  
Yinghua Wang ◽  
Hideki Takahashi

Plant root system architecture changes drastically in response to availability of macronutrients in the soil environment. Despite the importance of root sulfur (S) uptake in plant growth and reproduction, molecular mechanisms underlying root development in response to S availability have not been fully characterized. We report here on the signaling module composed of the CLAVATA3 (CLV3)/EMBRYO SURROUNDING REGION (CLE) peptide and CLAVATA1 (CLV1) leucine-rich repeat receptor kinase, which regulate lateral root (LR) development in Arabidopsis thaliana upon changes in S availability. The wild-type seedlings exposed to prolonged S deficiency showed a phenotype with low LR density, which was restored upon sulfate supply. In contrast, the clv1 mutant showed a higher daily increase rate of LR density relative to the wild-type under prolonged S deficiency, which was diminished to the wild-type level upon sulfate supply, suggesting that CLV1 directs a signal to inhibit LR development under S-deficient conditions. CLE2 and CLE3 transcript levels decreased under S deficiency and through CLV1-mediated feedback regulations, suggesting the levels of CLE peptide signals are adjusted during the course of LR development. This study demonstrates a fine-tuned mechanism for LR development coordinately regulated by CLE-CLV1 signaling and in response to changes in S availability.


2006 ◽  
Vol 19 (5) ◽  
pp. 471-479 ◽  
Author(s):  
Angela Carmen Morris ◽  
Michael Anthony Djordjevic

The clover-nodulating Rhizobium leguminosarum bv. trifolii ANU794 initiates normal root-nodule development with abnormally low efficiency on the Trifolium subterraneum cv. Woogenellup. The cellular and developmental responses of Woogenellup roots to the site- and dose-defined inoculation of green fluorescent protein (gfp)-labeled cells of ANU843 (nodulation proficient) and ANU794 was investigated using light, fluorescence, and confocal microscopy. Strain ANU794-gfp induced three primordia types and four developmental responses at the inoculation site: true or aberrant nodules (on 5 and 25% of plants, respectively), hybrid structures (20% of plants), or lateral roots (50% of plants). The novel hybrid structures possessed nodule and lateral root-like features and unusual vascular patterning. Strain ANU794-gfp induces lateral root formation by stimulating pericycle cell divisions at all nearby protoxylem poles. Only true nodules induced by ANU794-gfp contained intracellular bacteria. In contrast, strain ANU843-gfp induced nodules only and lateral root formation was suppressed at spot inoculation sites. Primordium types were distinguishable by the emission spectrum characteristics of phenolic UV-absorbing and fluorescent compounds that accumulate in primordium cells. Hybrid primordia contained (at least) two fluorescent cell populations, suggesting that they are chimeric. The results suggest that ANU794 may produce both nodule- and lateral root-generating signals simultaneously.


1976 ◽  
Vol 6 (3) ◽  
pp. 253-261 ◽  
Author(s):  
George A. Schier ◽  
Robert B. Campbell

Differences in suckering from root segments and in rooting from sucker cuttings were studied among four species of Populus, including three poplars, P. angustifolia James, P. deltoides Bartr., and P. balsamifera L., and an aspen, P. tremuloides Michx. Places where suckers originated on root segments were more variable in the poplars than in the aspen. Whereas suckers developed in the aspen only from the periderm, suckers developed in the poplars from the periderm and from cambium exposed at the cut ends of segments and lateral roots. Poplar suckers arising from the periderm originated from preexisting suppressed buds embedded in the periderm. Suckers developed in the aspen from preexisting primordia. Lateral root formation from preexisting and newly initiated meristems on root segments was common in the poplars but rare in the aspen. The presence of lateral roots increased sucker growth, and the development of suckers and lateral roots responded to the inherent polarity of the root segment. Sucker cuttings from the poplars were generally superior in rooting capacity to those from the aspen.


Author(s):  
Duong Tan Nhut ◽  
Nguyen Thi Nhat Linh ◽  
Nguyen Hoang Loc ◽  
Hoang Thanh Tung ◽  
Vu Thi Hien ◽  
...  

<p><em>Panax vietnamensis</em> (Ngoc Linh ginseng) plays critical roles in pharmaceutical industry because triterpenoid saponins from its roots produce medicine for improving health and treating many diseases. Metal nanoparticles reveal completely new or improved properties based on specific characteristics such as size, distribution and morphology compare to metal ion or salt; and their potential for <em>in vitro </em>plant cultures. Present study investigated the effects of metal nanoparticles including nZnO (0.5-2.5 mg/l), nAg (1-3 mg/l), and nCu (1-3 mg/l) supplemented in free-hormone-MS medium to <em>in vitro Panax vietnamensis </em>lateral root growth. Our results showed that metal nanoparticles have the positive effect on the growth of<em> in vitro P. vietnamensis </em>lateral<em> </em>roots with nAg, nCu, and nZnO. At different concentrations, <em>in vitro P. vietnamensis </em>lateral root growth also has various effects on the growth of lateral roots. In supplemented metal nanoparticle treatments, nCu is the most optimum for <em>in vitro P. vietnamensis</em> lateral root growth; the highest increase was obtained at 1.5 mg/l nCu treatment (99.3% lateral root formation and all root growth indexes are the highest). Besides, 2.5 mg/l nAg is also significantly noticed in ginseng root growth. However, the negative impact on the growth of the <em>in vitro P. vietnamensis</em> lateral roots showed when culture medium contained the highest concentration; such as the root growing inhibition of nCu and nAg above 2.5 mg/l. Especially, this decrease was higher with the application of nZnO0.5-2.5 mg/l (decrease the lateral root number) and 2.5 mg/l (decrease percent of lateral root formation).</p>


Spontaneous or auxin-induced lateral root formation in radish and Arabidopsis provides an efficient system in which to examine molecular and cellular events associated with the initiation of a new meristem. Subtracted cDNA libraries made at different times in lateral root initiation were used as a source of genes that are expressed differentially during this developmental process, and expression studies on a small gene family of ribosomal protein genes were conducted. From analysis of cell division patterns in pericycle cells the number of founder cells for lateral roots was established. By the use of in vitro growth assays lateral root formation was determined to be a two-stage process. First a primordium is formed, and subsequently a subset of primordial cells begins to function as the lateral root apical meristem. This mode of root development has implications for pattern formation in newly organizing organs.


2017 ◽  
Vol 126 (1C) ◽  
pp. 47
Author(s):  
Nguyễn Thị Nhật Linh ◽  
Hoàng Thanh Tùng ◽  
Vũ Thị Hiền ◽  
Vũ Quốc Luận ◽  
Nguyễn Phúc Huy ◽  
...  

<p><em>Panax vietnamensis</em> (Ngoc Linh ginseng) plays critical roles in pharmaceutical industry because triterpenoid saponins from its roots produce medicine for improving health and treating many diseases. Metal nanoparticles reveal completely new or improved properties based on specific characteristics such as size, distribution and morphology compare to metal ion or salt; and their potential for <em>in vitro </em>plant cultures. Present study investigated the effects of metal nanoparticles including nZnO (0.5-2.5 mg/l), nAg (1-3 mg/l), and nCu (1-3 mg/l) supplemented in free-hormone-MS medium to <em>in vitro Panax vietnamensis </em>lateral root growth. Our results showed that metal nanoparticles have the positive effect on the growth of<em> in vitro P. vietnamensis </em>lateral<em> </em>roots with nAg, nCu, and nZnO. At different concentrations, <em>in vitro P. vietnamensis </em>lateral root growth also has various effects on the growth of lateral roots. In supplemented metal nanoparticle treatments, nCu is the most optimum for <em>in vitro P. vietnamensis</em> lateral root growth; the highest increase was obtained at 1.5 mg/l nCu treatment (99.3% lateral root formation and all root growth indexes are the highest). Besides, 2.5 mg/l nAg is also significantly noticed in ginseng root growth. However, the negative impact on the growth of the <em>in vitro P. vietnamensis</em> lateral roots showed when culture medium contained the highest concentration; such as the root growing inhibition of nCu and nAg above 2.5 mg/l. Especially, this decrease was higher with the application of nZnO0.5-2.5 mg/l (decrease the lateral root number) and 2.5 mg/l (decrease percent of lateral root formation).</p>


2018 ◽  
Author(s):  
Priya Ramakrishna ◽  
Graham A Rance ◽  
Lam Dai Vu ◽  
Evan Murphy ◽  
Kamal Swarup ◽  
...  

ABSTRACTIn plants, post-embryonic formation of new organs helps shape the adult organism. This requires the tight regulation of when and where a new organ is formed, and a coordination of the underlying cell divisions. To build a root system, new lateral roots are continuously developing, and this process requires asymmetric cell division in adjacent pericycle cells. Characterization of an expansin a1 (expa1) mutant has revealed a novel checkpoint during lateral root formation. Specifically, a minimal pericycle width was found to be necessary and sufficient to trigger asymmetric pericycle cell divisions during auxin-driven lateral root formation. We conclude that a localized radial expansion of adjacent pericycle cells is required to position the asymmetric cell divisions and generate a core of small daughter cells, which is a prerequisite for lateral root organogenesis.SIGNFICANCE STATEMENTOrgan formation is an essential process in plants and animals, driven by cell division and cell identity establishment. Root branching, where lateral roots form along the primary root axis, increases the root system and aids capture of water and nutrients. We have discovered that tight control of cell width is necessary to co-ordinate asymmetric cell divisions in cells that give rise to a new lateral root organ. While biomechanical processes have been shown to play a role in plant organogenesis, including lateral root formation, our data give new mechanistic insights into the cell size checkpoint during lateral root initiation.


1986 ◽  
Vol 16 (5) ◽  
pp. 1135-1139 ◽  
Author(s):  
David G. Simpson

The effects of 1-napthaleneacetic acid (NAA) and 3-indolebutyric acid (IBA) soil drenches on lateral root formation and growth of interior Douglas-fir (Pseudotsugamenziesii var. glauca (Beissn.) Franco) seedlings were studied. At rates between 10−3 and 10−5 M, NAA was more effective than IBA in stimulating first-order lateral root formation. Seedling age influenced the degree of NAA-induced lateral root formation. At three different nurseries the greatest number of lateral roots was produced by seedlings receiving 10−4 M (18.62 mgL−1) NAA 30 days after sowing. Shoot height and dry weight were reduced, although not at the expense of root growth in some cases.


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