scholarly journals A plant lipocalin is required for retinal-mediated de novo root organogenesis

2020 ◽  
Author(s):  
Alexandra J. Dickinson ◽  
Jingyuan Zhang ◽  
Michael Luciano ◽  
Guy Wachsman ◽  
Martin Schnermann ◽  
...  
Keyword(s):  
Lateral Root ◽  
Binding Proteins ◽  
De Novo ◽  
Lateral Roots ◽  
Time Lapse ◽  
Homology Search ◽  
Lateral Root Development ◽  
Root Organogenesis ◽  
Retinoid Binding Proteins ◽  
Β Carotene

AbstractBranching of root systems enables the exploration and colonization of the soil environment. In Arabidopsis roots, de novo organogenesis of lateral roots is patterned by an oscillatory mechanism called the root clock, which is dependent on metabolites derived from the β-carotene pathway1, 2. Retinoids are β-carotene-derived regulators of organogenesis in the animal kingdom. To determine if retinoids function in plant development, we conducted time-lapse imaging of a chemical reporter for retinoid binding proteins. We found that it oscillates with a comparable frequency to the root clock and accurately predicts sites of lateral root organogenesis. Exogenous application of retinal to wild-type plants is sufficient to induce root clock oscillations and lateral root organogenesis. A homology search yielded a potential Arabidopsis homolog, TEMPERATURE INDUCED LIPOCALIN (TIL) to vertebrate retinoid binding proteins. Genetic analysis indicates that TIL is necessary for normal lateral root development and a til mutant has decreased retinal sensitivity. TIL expression in a heterologous system conferred retinal binding activity, suggesting that it may directly interact with this molecule. Together, these results demonstrate an essential role for retinal and for plant retinal binding proteins in lateral root organogenesis.

scholarly journals Auxin: at the root of nodule development?

2008 ◽  
Vol 35 (8) ◽  
pp. 651 ◽  
Author(s):  
Ulrike Mathesius
Keyword(s):  
Lateral Root ◽  
De Novo ◽  
Root Nodules ◽  
Lateral Roots ◽  
Nodule Development ◽  
Nodule Formation ◽  
Cortical Cells ◽  
Lateral Root Development ◽  
Organ Differentiation ◽  
Development And Differentiation

Root nodules are formed as a result of an orchestrated exchange of chemical signals between symbiotic nitrogen fixing bacteria and certain plants. In plants that form nodules in symbiosis with actinorhizal bacteria, nodules are derived from lateral roots. In most legumes, nodules are formed de novo from pericycle and cortical cells that are re-stimulated for division and differentiation by rhizobia. The ability of plants to nodulate has only evolved recently and it has, therefore, been suggested that nodule development is likely to have co-opted existing mechanisms for development and differentiation from lateral root formation. Auxin is an important regulator of cell division and differentiation, and changes in auxin accumulation and transport are essential for lateral root development. There is growing evidence that rhizobia alter the root auxin balance as a prerequisite for nodule formation, and that nodule numbers are regulated by shoot-to-root auxin transport. Whereas auxin requirements appear to be similar for lateral root and nodule primordium activation and organ differentiation, the major difference between the two developmental programs lies in the specification of founder cells. It is suggested that differing ratios of auxin and cytokinin are likely to specify the precursors of the different root organs.

Lateral root formation and nutrients: nitrogen in the spotlight

2021 ◽  
Author(s):  
Pierre-Mathieu Pélissier ◽  
Hans Motte ◽  
Tom Beeckman
Keyword(s):  
Signaling Pathways ◽  
Root System ◽  
Root Development ◽  
Lateral Root ◽  
Molecular Mechanisms ◽  
Root Formation ◽  
Lateral Roots ◽  
Nutrient Use Efficiency ◽  
Lateral Root Formation ◽  
Lateral Root Development

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.

OPR3 is expressed in phloem cells and is vital for lateral root development in Arabidopsis

2013 ◽  
Vol 93 (2) ◽  
pp. 165-170 ◽  
Author(s):  
Shuaizhang Li ◽  
Jiajia Ma ◽  
Pei Liu
Keyword(s):  
Root Development ◽  
Lateral Root ◽  
Lateral Roots ◽  
Gus Activity ◽  
Auxin Biosynthesis ◽  
Lateral Root Development ◽  
Helix Loop Helix ◽  
Meja Treatment ◽  
Potential Binding ◽  
Temporal And Spatial

Li, S., Ma, J. and Liu, P. 2013. OPR3 is expressed in phloem cells and is vital for lateral root development in Arabidopsis. Can. J. Plant Sci. 93: 165–170. Jasmonates, a group of oxylipin phytohormones in angiosperms, play important roles in regulating plant growth and development and in responding to environmental stimuli. AtOPR3, a 12-oxo-phytodienoic acid (OPDA) reductase in Arabidopsis thaliana, has been proven to be vital in catalyzing jasmonate biosynthesis. Here, the temporal and spatial expression of AtOPR3 was investigated by promoter-GUS fusion in A. thaliana. In pOPR3::GUS transgenic plants, the GUS activity was detected in roots, leaves and all floral organs, and was highly induced by MeJA treatment. In addition, the GUS activity was principally detected in the phloem cells of the leaf veins. The sequence of the OPR3 promoter region was predicted to have 49 potential binding sites for transcription factors including the well-known Myc-like basic helix-loop-helix, GATA, MADS, MYB-like and Homeobox proteins. In consistent with an expression of OPR3 in lateral roots, there are more lateral roots in the opr3 mutant plants, in which OPR3 expression is knocking-out. In addition, the involvement of auxin biosynthesis in JA-regulated lateral root development is implied by our observation that the transcripts of ASA1, a gene involved in auxin biosynthesis, are decreased in opr3 plants.

scholarly journals Development of Root Architecture in Thirty-seven Tree Species of Field Grown Nursery Stock1

2020 ◽  
Vol 38 (4) ◽  
pp. 143-148
Author(s):  
G. W. Watson ◽  
A.M. Hewitt
Keyword(s):  
Root System ◽  
Root Development ◽  
Lateral Root ◽  
Root Architecture ◽  
Lateral Roots ◽  
Acer Rubrum ◽  
Acer Pseudoplatanus ◽  
Lateral Root Development ◽  
Nursery Production ◽  
One Year

Abstract The number and size of lateral roots of a tree seedling can be evaluated visually, and could potentially be used to select plants with better root systems early in nursery production. To evaluate how root architecture develops in young trees, root architecture of 37 species of trees was compared at two stages of development: as harvested seedlings, and then one year after replanting. The total number of lateral roots and the number of roots >2mm (0.08 in) diameter that were present on the portion of the taproot remaining on seedlings after standard root pruning were recorded. Neither could consistently predict the number of lateral roots on the root system one year after replanting. Development of roots (sum of diameters) regenerated from the cut end of the seedling taproot was equal or greater than lateral root development in 84 percent of evaluated species. Even when regenerated root development was significantly less than lateral root development, the regenerated roots still comprised up to 44 percent of the root system. Regenerated roots from the cut end of the taproot can become a major component of the architecture of the structural root system in nursery stock. Index words: structural roots, nursery production, root regeneration. Species used in this study: European black alder (Alnus glutinosa Gaertn.), green ash (Fraxinus pennsylvanica Marshall), quaking aspen (Populus tremuloides Michx.), European white birch. (Betula pendula Roth), river birch (Betula nigra L.), black locust (Robinia pseudoacacia L.), northern catalpa (Catalpa speciosa (Warder) Warder ex Engelm.), Mazzard cherry [Prunus avium [L.) L.], chokecherry (Prunus virginiana L.), American elm (Ulmus americana L.), Siberian elm (Ulmus pumilia L.), goldenchain tree (Laburnum anagyroides Medik.), northern hackberry (Celtis occidentalis L.), Cockspur hawthorn (Crateagus crus-galli L.), single seed hawthorn (Crateagus monogyna Jacq.), honeylocust (Gleditsia tricanthos L.), Japanese pagodatree [Sophora japonica (L.) Schott], Katsura tree (Cercidiphyllum japonicum Siebold & Zucc.), Kentucky coffee tree [Gymnocladus dioicus (L.) K. Koch], littleleaf linden (Tilia cordata Mill.), boxelder (Acer negundo L.), hedge maple (Acer campestre L.), Norway maple (Acer platanoides L.), red maple (Acer rubrum L.), silver maple (Acer saccharinum L.), sugar maple (Acer saccharum Marshall), sycamore maple (Acer pseudoplatanus L.), English Oak (Quercus robur L.), northern red oak (Quercus rubra L.), Siberian peashrub (Caragana arborescens Lam.), American plum (Prunus Americana Marshall ), Myrobalan plum (Prunus cerasifera Ehrh.), redbud (Cercis Canadensis L.), Russian olive (Elaeagnus angustifoliaI L.), tuliptree (Liriodendron tulipifera L.), black walnut (Juglans nigra L.), Japanese zelkova (Zelkova serrata (Thunb.) Makino).

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 Oak Taproot Growth Disruption Differentially Impacts Root Architecture during Nursery Production

Forests ◽  
2020 ◽  
Vol 11 (8) ◽  
pp. 798
Author(s):  
Shanon Hankin ◽  
Gary Watson
Keyword(s):  
Root Development ◽  
Lateral Root ◽  
Root Architecture ◽  
Lateral Roots ◽  
Production Methods ◽  
Lateral Root Development ◽  
Root Regeneration ◽  
Nursery Production ◽  
Growth Disruption ◽  
Taproot Pruning

For urban trees with strong taproots, a shift in root growth towards increased lateral root development could improve tree performance in compacted, poorly drained urban soils. In effort to achieve this desired shift, various propagation and production practices exist within the nursery industry. However, the effectiveness of practices used to disrupt taproot development, as well as their impact on root architecture, has been largely undocumented. To determine how seedling root systems respond to taproot growth disruption, we pruned oak seedling taproots either mechanically at 5 and/or 15 cm, or via air pruning at 15 cm. Taproot regeneration and lateral root development were evaluated after two years. Taproot pruning resulted in multiple regenerated taproots. The location and number of times the taproot(s) was pruned did not appear to alter the ultimate number. Mechanical taproot pruning did not affect lateral root development above the first pruning cut location at 5 or 15 cm, but generally increased the density of lateral roots below the pruning cut, likely due to the multiple taproots present. Most lateral roots were fine roots less than 1 mm in diameter (fine roots), being unlikely to become long-lived components of the root system architecture. The average number of lateral roots on air pruned (AP) seedlings was generally greater than on the same taproot segment of control (C) seedlings. To determine how these seedling changes impact the root regeneration of liner stock, we planted both taproot pruned and taproot air pruned seedlings in in-ground fabric bags filled with field soil (B) or directly into the field without bags (F). Root regeneration potential (RRP) at the bottom and lateral surfaces of the root ball were evaluated. There was less RRP on the lateral surface of the root ball in taproot air pruned, container-grown (CG) compared to taproot pruned, bare root (BR) bur oak liners, and there was no difference in red oak liners. The multiple taproots of mechanically pruned BR seedlings did not result in excessive taproot development as liners. In contrast, CG seedling taproots restricted by air pruning produced more regenerated taproots after transplanting. While seedling taproot growth disruption does disrupt the growth of a dominant single taproot and alters the architecture toward increasing the number of lateral roots, these practices do not result in laterally dominated root architecture at the liner stage of nursery production. Future research should determine how these production methods effect lateral root growth after a tree is established in the landscape and determine appropriate combinations of production methods for different species.

Effects of IAA, Kinetin, and Trifluralin on Cotton Seedlings

Weed Science ◽  
1971 ◽  
Vol 19 (3) ◽  
pp. 265-268 ◽  
Author(s):  
Ghanem S. Hassawy ◽  
K. C. Hamilton
Keyword(s):  
Gossypium Hirsutum ◽  
Root Development ◽  
Lateral Root ◽  
Indoleacetic Acid ◽  
Lateral Roots ◽  
Primary Root ◽  
Lateral Root Development

Trifluralin (α,α,α-trifluoro-2,6-dinitro-N,N-dipropyl-p-toluidine), IAA (indoleacetic acid), kinetin (6-furfurylamino purine), and their combinations in culture solutions did not affect cotton (Gossypium hirsutumL., var. Deltapine Smooth Leaf) germination but reduced primary root and shoot lengths of seedlings. Trifluralin alone and in combination with IAA or kinetin inhibited lateral root development. When IAA and kinetin were both applied with 5 ppmw trifluralin, lateral roots developed.

scholarly journals Involvement of a truncated MADS-box transcription factor ZmTMM1 in root nitrate foraging

2020 ◽  
Vol 71 (15) ◽  
pp. 4547-4561
Author(s):  
Ying Liu ◽  
Zhongtao Jia ◽  
Xuelian Li ◽  
Zhangkui Wang ◽  
Fanjun Chen ◽  
...  
Keyword(s):  
Transcription Factor ◽  
Lateral Root ◽  
Lateral Roots ◽  
Morphological Plasticity ◽  
Underlying Mechanism ◽  
Grass Species ◽  
Mads Box ◽  
Genetic Redundancy ◽  
Root Branching ◽  
Lateral Root Development

Abstract Plants can develop root systems with distinct anatomical features and morphological plasticity to forage nutrients distributed heterogeneously in soils. Lateral root proliferation is a typical nutrient-foraging response to a local supply of nitrate, which has been investigated across many plant species. However, the underlying mechanism in maize roots remains largely unknown. Here, we report on identification of a maize truncated MIKC-type MADS-box transcription factor (ZmTMM1) lacking K- and C-domains, expressed preferentially in the lateral root branching zone and induced by the localized supply of nitrate. ZmTMM1 belongs to the AGL17-like MADS-box transcription factor family that contains orthologs of ANR1, a key regulator for root nitrate foraging in Arabidopsis. Ectopic overexpression of ZmTMM1 recovers the defective growth of lateral roots in the Arabidopsis anr1 agl21 double mutant. The local activation of glucocorticoid receptor fusion proteins for ZmTMM1 and an artificially truncated form of AtANR1 without the K- and C-domains stimulates the lateral root growth of the Arabidopsis anr1 agl21 mutant, providing evidence that ZmTMM1 encodes a functional MADS-box that modulates lateral root development. However, no phenotype was observed in ZmTMM1-RNAi transgenic maize lines, suggesting a possible genetic redundancy of ZmTMM1 with other AGL17-like genes in maize. A comparative genome analysis further suggests that a nitrate-inducible transcriptional regulation is probably conserved in both truncated and non-truncated forms of ZmTMM1-like MADS-box transcription factors found in grass species.

scholarly journals Natural variation identifies a Pxy gene controlling root vascular organization and formation of nodules and lateral roots in Lotus japonicus

2020 ◽  
Author(s):  
Yasuyuki Kawaharada ◽  
Niels Sandal ◽  
Vikas Gupta ◽  
Haojie Jin ◽  
Maya Kawaharada ◽  
...  
Keyword(s):  
Lateral Root ◽  
Reverse Genetics ◽  
De Novo ◽  
Lateral Roots ◽  
Lotus Japonicus ◽  
Nodule Formation ◽  
Mesorhizobium Loti ◽  
Genetic Overlap ◽  
Natural Variants ◽  
Trait Locus

AbstractForward and reverse genetics using the model legumes Lotus japonicus and Medicago truncatula have been instrumental for identifying the essential genes governing legume-rhizobial symbiosis. However, little is known about the effects of intraspecific variation on symbiotic signaling. The Lotus accessions Gifu and MG20 show differentiated phenotypic responses to the Mesorhizobium loti exoU mutant that produces truncated exopolysaccharides. Using Quantitative Trait Locus sequencing (QTL-seq), we identify the Pxy gene as a component of this differential exoU response. Lotus Pxy encodes a leucine-rich-repeat kinase similar to Arabidopsis PXY, which regulates stem vascular development. We show that Lotus pxy insertion mutants display defects in root vascular organization, as well as lateral root and nodule formation. Our work links Pxy to de novo organogenesis in the root, highlights the genetic overlap between regulation of lateral root and nodule formation, and demonstrates that specific natural variants of Pxy differentially affect nodulation signaling.

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