scholarly journals At-Hook Motif Nuclear Localised Protein 18 as a Novel Modulator of Root System Architecture

2020 ◽  
Vol 21 (5) ◽  
pp. 1886 ◽  
Author(s):  
Marek Širl ◽  
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 is involved in regulation of 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 a decreased LRP initiation. The over-expression of AHL18 results in a more extensive root system, longer primary roots, and increased density of lateral root initiation events. AHL18 is thus involved in the formation of lateral roots at both LRP initiation and their later development. We conclude that AHL18 participates in modulation of root system architecture through regulation of root apical meristem activity, lateral root initiation and emergence; these correspond well with expression pattern of AHL18.

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 A single cell view of the transcriptome during lateral root initiation in Arabidopsis thaliana

2020 ◽  
Author(s):  
Hardik P. Gala ◽  
Amy Lanctot ◽  
Ken Jean-Baptiste ◽  
Sarah Guiziou ◽  
Jonah C. Chu ◽  
...  
Keyword(s):  
Single Cell ◽  
Root Development ◽  
Lateral Root ◽  
Lateral Roots ◽  
Primary Root ◽  
Root Initiation ◽  
Lateral Root Primordia ◽  
Lateral Root Development ◽  
Lateral Root Initiation ◽  
Molecular Events

AbstractRoot architecture is a major determinant of fitness, and is under constant modification in response to favorable and unfavorable environmental stimuli. Beyond impacts on the primary root, the environment can alter the position, spacing, density and length of secondary or lateral roots. Lateral root development is among the best-studied examples of plant organogenesis, yet there are still many unanswered questions about its earliest steps. Among the challenges faced in capturing these first molecular events is the fact that this process occurs in a small number of cells with unpredictable timing. Single-cell sequencing methods afford the opportunity to isolate the specific transcriptional changes occurring in cells undergoing this fate transition. Using this approach, we successfully captured the transcriptomes of initiating lateral root primordia, and discovered many previously unreported upregulated genes associated with this process. We developed a method to selectively repress target gene transcription in the xylem pole pericycle cells where lateral roots originate, and demonstrated that expression of several of these targets was required for normal root development. We also discovered novel subpopulations of cells in the pericycle and endodermal cell files that respond to lateral root initiation, highlighting the coordination across cell files required for this fate transition.One sentence summarySingle cell RNA sequencing reveals new molecular details about lateral root initiation, including the transcriptional impacts of the primordia on bordering cells.

scholarly journals Systemic signalling through translationally controlled tumour protein controls lateral root formation in Arabidopsis

2019 ◽  
Vol 70 (15) ◽  
pp. 3927-3940 ◽  
Author(s):  
Rémi Branco ◽  
Josette Masle
Keyword(s):  
Lateral Root ◽  
Root Elongation ◽  
Developmental Plasticity ◽  
Lateral Roots ◽  
Primary Root ◽  
Dual Function ◽  
Growth Promoter ◽  
Root Initiation ◽  
Long Distance ◽  
Lateral Root Initiation

Abstract The plant body plan and primary organs are established during embryogenesis. However, in contrast to animals, plants have the ability to generate new organs throughout their whole life. These give them an extraordinary developmental plasticity to modulate their size and architecture according to environmental constraints and opportunities. How this plasticity is regulated at the whole-organism level is elusive. Here we provide evidence for a role for translationally controlled tumour protein (TCTP) in regulating the iterative formation of lateral roots in Arabidopsis. AtTCTP1 modulates root system architecture through a dual function: as a general constitutive growth promoter enhancing root elongation and as a systemic signalling agent via mobility in the vasculature. AtTCTP1 encodes mRNAs with long-distance mobility between the shoot and roots. Mobile shoot-derived TCTP1 gene products act specifically to enhance the frequency of lateral root initiation and emergence sites along the primary root pericycle, while root elongation is controlled by local constitutive TCTP1 expression and scion size. These findings uncover a novel type for an integrative signal in the control of lateral root initiation and the compromise for roots between branching more profusely or elongating further. They also provide the first evidence in plants of an extracellular function of the vital, highly expressed ubiquitous TCTP1.

Application of Phytohormones to Pea Roots After Removal of the Apex: Effect on Lateral Root Production

1979 ◽  
Vol 6 (2) ◽  
pp. 195 ◽  
Author(s):  
PB Goodwin ◽  
SC Morris
Keyword(s):  
Lateral Root ◽  
Lateral Roots ◽  
Primary Root ◽  
Root Production ◽  
Root Tip ◽  
Naphthaleneacetic Acid ◽  
Root Initiation ◽  
Lateral Root Initiation ◽  
Lateral Bud ◽  
Bud Growth

Removal of 2 mm of the primary root tip of Pisum sativum caused a complete halt to primary root elongation, but did not alter the total number of laterals formed. The auxins indole-3-acetic acid and 1-naphthaleneacetic acid, when applied to the stump in a lanolin emulsion, increased the number of lateral roots. High levels of abscisic acid and low levels of the cytokinins N6-benzylaminopurine and N6-(γ, γ-dimethylallylamino)purine, and of the gibberellins GA3 and GA7, resulted in decreased lateral root production. Kinetin was without effect. There appears to be an inverse relationship between auxins and cytokinins in root/shoot growth coordination. Auxins, which are produced in the shoot tip, inhibit lateral bud growth but promote lateral root initiation. Cytokinins, which are produced in the root tip, inhibit lateral root initiation, but promote lateral stem growth.

scholarly journals Analysis of Root System Architecture Affected by Swarming Behavior

2020 ◽  
Vol 28 (1) ◽  
pp. 1-12
Author(s):  
Songyang Li ◽  
Wenqi Yu ◽  
Xiaodong Liu ◽  
Miao Wang
Keyword(s):  
Root System ◽  
System Architecture ◽  
Root Length ◽  
Lateral Roots ◽  
Primary Root ◽  
Morphological Characteristics ◽  
Root System Architecture ◽  
Behavior Model ◽  
Single Root ◽  
Swarming Behavior

AbstractThe root system architecture (RSA) displays complex morphological characteristics because of diverse root growth behaviors. Recent studies have revealed that swarming behavior among roots is particularly important for RSA to adapt to environmental stimuli. However, few models are proposed to simulate RSA based on swarming behavior of roots. To analyze plasticity of RSA affected by swarming behavior, we propose viewing it as a swarm of single roots. A swarming behavior model is proposed by considering repulsion, alignment, and preference of individual single roots. Then, the swarming behavior model is integrated into a simple and generic RSA model (called ArchiSimple). Lastly, characteristics of RSA affected by swarming behavior model and non-swarming behavior model are compared and analyzed under three different virtual soil sets. The characteristics of RSA (such as primary root length, lateral root length, lateral roots, and resource uptake) are significantly promoted by swarming behavior. Root system distributions can also be greatly affected by swarming behavior. These results show that root foraging and exploration in soil can be regarded as collective behavior of individual single root.

scholarly journals Disruption of CYCLOPHILIN 38 function reveals a photosynthesis-dependent systemic signal controlling lateral root emergence

2020 ◽  
Author(s):  
Lina Duan ◽  
Juan Manuel Pérez-Ruiz ◽  
Francisco Javier Cejudo ◽  
José R. Dinneny
Keyword(s):  
Root Growth ◽  
Root System ◽  
Lateral Root ◽  
System Development ◽  
Lateral Roots ◽  
Primary Root ◽  
Root System Architecture ◽  
Minor Effect ◽  
Low Light ◽  
Primary Root Growth

AbstractPhotosynthesis in leaves generates the fixed-carbon resources and essential metabolites that support sink tissues, such as roots [1]. One of these products, sucrose, is known to promote primary root growth, but it is not clear what other molecules may be involved and whether other stages of root system development are affected by photosynthate levels [2]. Through a mutant screen to identify pathways regulating root system architecture, we identified a mutation in the CYCLOPHILIN 38 (CYP38) gene, which causes an accumulation of pre-emergent stage lateral roots, with a minor effect on primary root growth. CYP38 was previously reported to maintain the stability of Photosystem II (PSII) in chloroplasts [3]. CYP38 expression is enriched in the shoot and grafting experiments show that the gene acts non-cell autonomously to promote lateral root emergence. Growth of wild-type plants under low light conditions phenocopied the cyp38 lateral root emergence phenotype as did the inhibition of PSII-dependent electron transport or NADPH production. Importantly, the cyp38 root phenotype is not rescued by exogenous sucrose, suggesting the involvement of another metabolite. Auxin (IAA) is an essential hormone promoting root growth and its biosynthesis from tryptophan is dependent on reductant generated during photosynthesis [4,5]. Both WT seedlings grown under low light and cyp38 mutants have highly diminished levels of IAA in root tissues. The cyp38 lateral root defect is rescued by IAA treatment, revealing that photosynthesis promotes lateral root emergence partly through IAA biosynthesis. Metabolomic profiling shows that the accumulation of several defense-related metabolites are also photosynthesis-dependent, suggesting that the regulation of a number of energy-intensive pathways are down-regulated when light becomes limiting.

scholarly journals Nitrate Signaling, Functions, and Regulation of Root System Architecture: Insights from Arabidopsis thaliana

Genes ◽  
2020 ◽  
Vol 11 (6) ◽  
pp. 633 ◽  
Author(s):  
Muhammad Asim ◽  
Zia Ullah ◽  
Fangzheng Xu ◽  
Lulu An ◽  
Oluwaseun Olayemi Aluko ◽  
...  
Keyword(s):  
Arabidopsis Thaliana ◽  
Root System ◽  
Root Development ◽  
System Architecture ◽  
Lateral Root ◽  
Transcriptional Regulatory Network ◽  
Primary Root ◽  
Root System Architecture ◽  
Nitrate Transporter ◽  
Nitrate Transporters

Root system architecture (RSA) is required for the acquisition of water and mineral nutrients from the soil. One of the essential nutrients, nitrate (NO3−), is sensed and transported by nitrate transporters NRT1.1 and NRT2.1 in the plants. Nitrate transporter 1.1 (NRT1.1) is a dual-affinity nitrate transporter phosphorylated at the T101 residue by calcineurin B-like interacting protein kinase (CIPKs); it also regulates the expression of other key nitrate assimilatory genes. The differential phosphorylation (phosphorylation and dephosphorylation) strategies and underlying Ca2+ signaling mechanism of NRT1.1 stimulate lateral root growth by activating the auxin transport activity and Ca2+-ANR1 signaling at the plasma membrane and the endosomes, respectively. NO3− additionally functions as a signal molecule that forms a signaling system, which consists of a vast array of transcription factors that control root system architecture that either stimulate or inhibit lateral and primary root development in response to localized and high nitrate (NO3−), respectively. This review elucidates the so-far identified nitrate transporters, nitrate sensing, signal transduction, and the key roles of nitrate transporters and its downstream transcriptional regulatory network in the primary and lateral root development in Arabidopsis thaliana under stress conditions.

scholarly journals Same same, but different: growth responses of primary and lateral roots

2020 ◽  
Vol 71 (8) ◽  
pp. 2397-2411 ◽  
Author(s):  
Sascha Waidmann ◽  
Elizabeth Sarkel ◽  
Jürgen Kleine-Vehn
Keyword(s):  
Root System ◽  
Lateral Root ◽  
Growth Regulation ◽  
Lateral Roots ◽  
Primary Root ◽  
Spatial Arrangement ◽  
Root System Architecture ◽  
Growth Responses ◽  
Lateral Root Primordia ◽  
Organ Growth

Abstract The root system architecture describes the shape and spatial arrangement of roots within the soil. Its spatial distribution depends on growth and branching rates as well as directional organ growth. The embryonic primary root gives rise to lateral (secondary) roots, and the ratio of both root types changes over the life span of a plant. Most studies have focused on the growth of primary roots and the development of lateral root primordia. Comparably less is known about the growth regulation of secondary root organs. Here, we review similarities and differences between primary and lateral root organ growth, and emphasize particularly how external stimuli and internal signals differentially integrate root system growth.

scholarly journals Phenotyping Root System Architecture of Cotton (Gossypium barbadense L.) Grown Under Salinity

2017 ◽  
Vol 63 (4) ◽  
pp. 142-150 ◽  
Author(s):  
Shady A. Mottaleb ◽  
Essam Darwish ◽  
Menna Mostafa ◽  
Gehan Safwat
Keyword(s):  
Root System ◽  
System Architecture ◽  
Root Length ◽  
Lateral Root ◽  
Lateral Roots ◽  
Root System Architecture ◽  
Gossypium Barbadense ◽  
Shoot Biomass ◽  
Peat Moss ◽  
Main Root

Abstract Soil salinity causes an annual deep negative impact to the global agricultural economy. In this study, the effects of salinity on early seedling physiology of two Egyptian cotton (Gossypium barbadense L.) cultivars differing in their salinity tolerance were examined. Also the potential use of a low cost mini-rhizotron system to measure variation in root system architecture (RSA) traits existing in both cultivars was assessed. Salt tolerant cotton cultivar ‘Giza 90’ produced significantly higher root and shoot biomass, accumulated lower Na+/K+ ratio through a higher Na+ exclusion from both roots and leaves as well as synthesized higher proline contents compared to salt sensitive ‘Giza 45’ cultivar. Measuring RSA in mini-rhizotrons containing solid MS nutrient medium as substrate proved to be more precise and efficient than peat moss/sand mixture. We report superior values of main root growth rate, total root system size, main root length, higher number of lateral roots and average lateral root length in ‘Giza 90’ under salinity. Higher lateral root density and length together with higher root tissue tolerance of Na+ ions in ‘Giza 90’ give it an advantage to be used as donor genotype for desirable root traits to other elite cultivars.

Natural genetic variation of Arabidopsis thaliana root morphological response to magnesium supply

2015 ◽  
Vol 66 (12) ◽  
pp. 1249 ◽  
Author(s):  
Qiying Xiao ◽  
Hugues De Gernier ◽  
László Kupcsik ◽  
Jérôme De Pessemier ◽  
Klaus Dittert ◽  
...  
Keyword(s):  
Arabidopsis Thaliana ◽  
Root System ◽  
Root Morphology ◽  
System Architecture ◽  
Lateral Roots ◽  
Iron Concentration ◽  
Primary Root ◽  
Root System Architecture ◽  
Mineral Nutrient ◽  
Nutrient Distribution

Plants dynamically cope with the variability of mineral nutrient distribution in soil by constantly modulating nutrient uptake and shaping root-system architecture. The changes in root morphology in response to major essential elements are largely documented, but little is known about how the root system responds to magnesium (Mg) availability. Thirty-six natural accessions of the model species Arabidopsis thaliana were subjected to an in vitro screen for identifying variation in root system architecture in response to Mg availability. Response of root morphology was observed on 2-dimensional agar plates. Low Mg supply repressed the elongation of the lateral roots more than of the primary root. However, some accessions exhibited higher number and length of lateral roots than the reference Columbia-0. Across all accessions, the root morphological traits did not correlate with tissue Mg concentrations. Interestingly, shoot calcium and root phosphorus concentrations were positively correlated with the number and length of lateral roots, whereas root iron concentration was negatively correlated with the primary root length. The diversity of root phenotypes identified in this report is a useful resource to study the genetic component determining root morphology in response to Mg availability.

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