scholarly journals Oscillating Gene Expression Determines Competence for Periodic Arabidopsis Root Branching

Science ◽  
2010 ◽  
Vol 329 (5997) ◽  
pp. 1306-1311 ◽  
Author(s):  
Miguel A. Moreno-Risueno ◽  
Jaimie M. Van Norman ◽  
Antonio Moreno ◽  
Jingyuan Zhang ◽  
Sebastian E. Ahnert ◽  
...  
Keyword(s):  
Animal Species ◽  
Lateral Roots ◽  
Transcriptional Regulators ◽  
Root Tip ◽  
Genetic Studies ◽  
Arabidopsis Root ◽  
Root Branching ◽  
Developmental Mechanism ◽  
Primary Axis ◽  
Cyclic Expression

Plants and animals produce modular developmental units in a periodic fashion. In plants, lateral roots form as repeating units along the root primary axis; however, the developmental mechanism regulating this process is unknown. We found that cyclic expression pulses of a reporter gene mark the position of future lateral roots by establishing prebranch sites and that prebranch site production and root bending are periodic. Microarray and promoter-luciferase studies revealed two sets of genes oscillating in opposite phases at the root tip. Genetic studies show that some oscillating transcriptional regulators are required for periodicity in one or both developmental processes. This molecular mechanism has characteristics that resemble molecular clock–driven activities in animal species.

scholarly journals Growth is required for perception of water availability to pattern root branches in plants

2018 ◽  
Vol 115 (4) ◽  
pp. E822-E831 ◽  
Author(s):  
Neil E. Robbins ◽  
José R. Dinneny
Keyword(s):  
Water Potential ◽  
Water Availability ◽  
Water Movement ◽  
Lateral Roots ◽  
Growth Zone ◽  
High Water ◽  
Developmental Competence ◽  
Root Tip ◽  
Root Branching ◽  
Lateral Branches

Water availability is a potent regulator of plant development and induces root branching through a process termed hydropatterning. Hydropatterning enables roots to position lateral branches toward regions of high water availability, such as wet soil or agar media, while preventing their emergence where water is less available, such as in air. The mechanism by which roots perceive the spatial distribution of water during hydropatterning is unknown. Using primary roots of Zea mays (maize) we reveal that developmental competence for hydropatterning is limited to the growth zone of the root tip. Past work has shown that growth generates gradients in water potential across an organ when asymmetries exist in the distribution of available water. Using mathematical modeling, we predict that substantial growth-sustained water potential gradients are also generated in the hydropatterning competent zone and that such biophysical cues inform the patterning of lateral roots. Using diverse chemical and environmental treatments we experimentally demonstrate that growth is necessary for normal hydropatterning of lateral roots. Transcriptomic characterization of the local response of tissues to a moist surface or air revealed extensive regulation of signaling and physiological pathways, some of which we show are growth-dependent. Our work supports a “sense-by-growth” mechanism governing hydropatterning, by which water availability cues are rendered interpretable through growth-sustained water movement.

scholarly journals The Arabidopsis Root Tip (Phospho)Proteomes at Growth-Promoting versus Growth-Repressing Conditions Reveal Novel Root Growth Regulators

Cells ◽  
2021 ◽  
Vol 10 (7) ◽  
pp. 1665
Author(s):  
Natalia Nikonorova ◽  
Evan Murphy ◽  
Cassio Flavio Fonseca de Lima ◽  
Shanshuo Zhu ◽  
Brigitte van de Cotte ◽  
...  
Keyword(s):  
Cell Wall ◽  
Root Growth ◽  
Growth Regulators ◽  
Growth Regulation ◽  
Phosphorylation Site ◽  
Primary Root ◽  
Root Tip ◽  
Arabidopsis Root ◽  
Growth Promoting ◽  
The Impact

Auxin plays a dual role in growth regulation and, depending on the tissue and concentration of the hormone, it can either promote or inhibit division and expansion processes in plants. Recent studies have revealed that, beyond transcriptional reprogramming, alternative auxin-controlled mechanisms regulate root growth. Here, we explored the impact of different concentrations of the synthetic auxin NAA that establish growth-promoting and -repressing conditions on the root tip proteome and phosphoproteome, generating a unique resource. From the phosphoproteome data, we pinpointed (novel) growth regulators, such as the RALF34-THE1 module. Our results, together with previously published studies, suggest that auxin, H+-ATPases, cell wall modifications and cell wall sensing receptor-like kinases are tightly embedded in a pathway regulating cell elongation. Furthermore, our study assigned a novel role to MKK2 as a regulator of primary root growth and a (potential) regulator of auxin biosynthesis and signalling, and suggests the importance of the MKK2 Thr31 phosphorylation site for growth regulation in the Arabidopsis root tip.

scholarly journals Mapping sites of gibberellin biosynthesis in the Arabidopsis root tip

2020 ◽  
Vol 229 (3) ◽  
pp. 1521-1534
Author(s):  
Richard Barker ◽  
Maria Nieves Fernandez Garcia ◽  
Stephen J. Powers ◽  
Simon Vaughan ◽  
Malcolm J. Bennett ◽  
...  
Keyword(s):  
Root Tip ◽  
Gibberellin Biosynthesis ◽  
Arabidopsis Root

scholarly journals Effects of Phosphate Shortage on Root Growth and Hormone Content of Barley Depend on Capacity of the Roots to Accumulate ABA

Plants ◽  
2020 ◽  
Vol 9 (12) ◽  
pp. 1722
Author(s):  
Lidiya Vysotskaya ◽  
Guzel Akhiyarova ◽  
Arina Feoktistova ◽  
Zarina Akhtyamova ◽  
Alla Korobova ◽  
...  
Keyword(s):  
Root Growth ◽  
Lateral Roots ◽  
Primary Root ◽  
Growth Responses ◽  
Root Tips ◽  
P Deficiency ◽  
Root Branching ◽  
Auxin Concentration ◽  
Shoot Mass ◽  
Primary Root Length

Although changes in root architecture in response to the environment can optimize mineral and water nutrient uptake, mechanisms regulating these changes are not well-understood. We investigated whether P deprivation effects on root development are mediated by abscisic acid (ABA) and its interactions with other hormones. The ABA-deficient barley mutant Az34 and its wild-type (WT) were grown in P-deprived and P-replete conditions, and hormones were measured in whole roots and root tips. Although P deprivation decreased growth in shoot mass similarly in both genotypes, only the WT increased primary root length and number of lateral roots. The effect was accompanied by ABA accumulation in root tips, a response not seen in Az34. Increased ABA in P-deprived WT was accompanied by decreased concentrations of cytokinin, an inhibitor of root extension. Furthermore, P-deficiency in the WT increased auxin concentration in whole root systems in association with increased root branching. In the ABA-deficient mutant, P-starvation failed to stimulate root elongation or promote branching, and there was no decline in cytokinin and no increase in auxin. The results demonstrate ABA’s ability to mediate in root growth responses to P starvation in barley, an effect linked to its effects on cytokinin and auxin concentrations.

Phytotoxic effects of phenolic compounds on Calopogonium mucunoides (Fabaceae) roots

2015 ◽  
Vol 63 (8) ◽  
pp. 679 ◽  
Author(s):  
Roberta Cristiane Ribeiro ◽  
Rodrigo Barbosa Braga Feitoza ◽  
Helena Regina Pinto Lima ◽  
Mário Geraldo de Carvalho
Keyword(s):  
Phenolic Compounds ◽  
Cinnamic Acid ◽  
Lateral Roots ◽  
Anatomical Variations ◽  
Root Diameter ◽  
Root Tip ◽  
Root Structure ◽  
Water Control ◽  
Calopogonium Mucunoides ◽  
Standard Techniques

Studies on phenols have gained attention owing to their abundance in plants and their effects on plant development. Phenols from forage grasses may exert phytotoxicity on legume crops in intercropping systems. We aimed to identify morpho-anatomical variations in Calopogonium mucunoides Desv. roots treated with phenolic compounds. Seeds of C. mucunoides were treated with (1) distilled water (control), (2) trans-cinnamic acid, (3) a mixture of the flavonoids quercetin, rutin, kaempferol and kaempferol-3-α-rhamnoside, or (4) a combination of the flavonoid mixture and trans-cinnamic acid. After 10 days of treatment, the roots were measured, described and processed according to standard techniques in plant anatomy. In general, non-control individuals showed plant lengths decreased by 40–45%, root-tip necrosis and intense lateral root ramification. Seeds germinated in cinnamic acid presented xylem poles with a greater number of cells and a greater emission of lateral roots. In the seeds treated with flavonoids, cell division was observed in the endodermis and the pericycle, and xylem fibres went through differentiation. The combination of cinnamic acid and flavonoids led to the premature formation of fibres by the phloem. The treatments with flavonoids or cinnamic acid alone were significantly greater in root diameter (868.61 µm and 810.35 µm, respectively) than was the application of both (714.98 µm) or the control (533.76 µm). The results suggest that cinnamic acid and the tested flavonoids negatively affect the development and the root structure of C. mucunoides.

Corrigendum - Factors which affects the growth of grain legumes on a solonized brown soil. I. Genotypic responses to soil physical factors

1991 ◽  
Vol 42 (1) ◽  
pp. 95
Author(s):  
BJ Atwell
Keyword(s):  
Root Growth ◽  
Water Status ◽  
Lateral Roots ◽  
Primary Root ◽  
Grain Legumes ◽  
Root Tip ◽  
Physical Factors ◽  
Brown Soil ◽  
Penetrometer Resistance ◽  
System L

Lupins (Lupinus angustifolius cvv. Yandee and 75A-258 and L. pilosus cv. P. 20957) and pea (Pisum sativum cv. Dundale) were grown in the field for 43 days on a solonized brown soil. Shoots of L. pilosus and peas grew most rapidly, while L. angustifolius cv. 75A-258 developed a relatively large root system. L. angustifolius cv. Yandee, a commercial lupin cultivar, was poorly adapted; shoot growth was restricted and roots ceased growing 36 days after sowing. The soil factors responsible for these widely differing responses were investigated. Once primary roots of L. angustifolius were 20-30 cm deep, root extension was slow or arrested. Indeed, primary root apices of Yandee were often necrotic in the soil below 20 cm. In contrast, roots proliferated rapidly in the surface 20 cm of the soil, particularly in 7SA-258, suggesting that factors in the deeper soil layers restricted root growth most severely. The vigorous growth of lateral roots of 75A-258 was reflected in a 2.6 fold greater total root length than for Yandee 43 days after sowing. Soil physical properties were not considered a likely explanation for these observations; soil water status and porosity were always favourable for root growth and root sections indicated that no cortical degradation, typical of O2 deficient roots, had occurred. Penetrometer resistance and root tip osmotic pressures suggested that poor root growth could not be ascribed simply to soil mechanical properties. The results suggest, by inference, that soil chemical factors could underlie the phenotypic responses observed.

scholarly journals Modelling time variations of root diameter and elongation rate as related to assimilate supply and demand

2020 ◽  
Vol 71 (12) ◽  
pp. 3524-3534
Author(s):  
Loïc Pagès ◽  
Marie Bernert ◽  
Guillaume Pagès
Keyword(s):  
Root System ◽  
Root Elongation ◽  
Lateral Roots ◽  
Supply And Demand ◽  
Root System Architecture ◽  
Elongation Rate ◽  
Growth Patterns ◽  
Root Tip ◽  
Generic Model ◽  
Maximal Diameter

Abstract In a given root system, individual roots usually exhibit a rather homogeneous tip structure although highly different diameters and growth patterns, and this diversity is of prime importance in the definition of the whole root system architecture and foraging characteristics. In order to represent and predict this diversity, we built a simple and generic model at root tip level combining structural and functional knowledge on root elongation. The tip diameter, reflecting meristem size, is used as a driving variable of elongation. It varies, in response to the fluctuations of photo-assimilate availability, between two limits (minimal and maximal diameter). The elongation rate is assumed to be dependent on the transient value of the diameter. Elongation stops when the tip reaches the minimal diameter. The model could satisfactorily reproduce patterns of root elongation and tip diameter changes observed in various species at different scales. Although continuous, the model could generate divergent root classes as classically observed within populations of lateral roots. This model should help interpret the large plasticity of root elongation patterns which can be obtained in response to different combinations of endogenous and exogenous factors. The parameters could be used in phenotyping the root system.

Expression of a Bet v 1 homologue gene encoding a PR 10 protein in birch roots: induction by auxin and localization of the transcripts by in situ hybridization

2001 ◽  
Vol 28 (1) ◽  
pp. 57 ◽  
Author(s):  
Pascal Poupard ◽  
Nicole Brunel ◽  
Nathalie Leduc ◽  
Jean-Daniel Viémont ◽  
Désiré-Georges Strullu ◽  
...  
Keyword(s):  
In Situ Hybridization ◽  
Abiotic Factors ◽  
Lateral Roots ◽  
Northern Blotting ◽  
Root Tip ◽  
Gene Encoding ◽  
High Accumulation ◽  
Bet V 1 ◽  
Polymerase Chain

In birch roots (Betula pendula Roth), two members of the Bet v 1 gene family which encode PR 10 proteins have previously been characterized. One of these members, named Bet v 1-sc1, is significantly induced in response to biotic or abiotic factors. We have analysed the expression of Bet v 1-sc1 in birch roots treated either with 1 M indole-3-acetic acid (IAA) or 1 M kinetin using reverse transcription–polymerase chain reaction (RT–PCR), northern blotting and competitive PCR. High accumulation of the Bet v 1-sc1 transcripts was recorded only after auxin application, while kinetin had no effect. By in situ hybridization, we have investigated the localization of Bet v 1-sc1 mRNA in birch roots after induction of the gene by root treatment with 1 M IAA. Using root tip sections, we showed that Bet v 1-sc1 is significantly expressed in the apical meristem and the procambium. In sections taken in the zone producing lateral roots, the presence of Bet v 1-sc1 was found at sites of emerging secondary root primordia. This first report of localization of Bet v 1-sc1 expression suggests that this gene could be involved in the processes leading to lateral root initiation.

scholarly journals Repression of early lateral root initiation events by transient water deficit in barley and maize

2012 ◽  
Vol 367 (1595) ◽  
pp. 1534-1541 ◽  
Author(s):  
Aurélie Babé ◽  
Tristan Lavigne ◽  
Jean-Philippe Séverin ◽  
Kerstin A. Nagel ◽  
Achim Walter ◽  
...  
Keyword(s):  
Water Deficit ◽  
Developmental Plasticity ◽  
Lateral Roots ◽  
Time Lapse ◽  
Root System Architecture ◽  
Negative Control ◽  
Root Branching ◽  
Branching Patterns ◽  
Primary Determinant ◽  
Key Driver

The formation of lateral roots (LRs) is a key driver of root system architecture and developmental plasticity. The first stage of LR formation, which leads to the acquisition of founder cell identity in the pericycle, is the primary determinant of root branching patterns. The fact that initiation events occur asynchronously in a very small number of cells inside the parent root has been a major difficulty in the study of the molecular regulation of branching patterns. Inducible systems that trigger synchronous lateral formation at predictable sites have proven extremely valuable in Arabidopsis to decipher the first steps of LR formation. Here, we present a LR repression system for cereals that relies on a transient water-deficit treatment, which blocks LR initiation before the first formative divisions. Using a time-lapse approach, we analysed the dynamics of this repression along growing roots and were able to show that it targets a very narrow developmental window of the initiation process. Interestingly, the repression can be exploited to obtain negative control root samples where LR initiation is absent. This system could be instrumental in the analysis of the molecular basis of drought-responsive as well as intrinsic pathways of LR formation in cereals.

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