scholarly journals Tomato roots sense horizontal/vertical mechanical impedance and divergently modulate root/shoot metabolome

2021 ◽  
Author(s):  
Alka Kumari ◽  
Sapana Nongmaithem ◽  
Sameera Devulapalli ◽  
Yellamaraju Sreelakshmi ◽  
Rameshwar Sharma
Keyword(s):  
Lateral Roots ◽  
Primary Root ◽  
Mechanical Impedance ◽  
Common Denominator ◽  
Root Tips ◽  
Vertical Orientation ◽  
Tomato Seedlings ◽  
Primary Roots ◽  
Tomato Roots ◽  
Metabolite Profiles

AbstractPlant roots encounter coarse environs right after emergence from the seeds. Little is known about metabolic changes enabling roots to overcome the soil impedance. Tomato seedlings grown vertically or horizontally, at increasing hardness, exhibited lateral roots proliferation, shorter hypocotyls, and primary roots. In primary root tips, hardness-elicited loss of amyloplasts staining; induced ROS and NO accumulation. The levels of IBA, zeatin, jasmonates, and salicylic acids markedly differed in roots and shoots exposed to increasing hardness. Hardness lowered IAA and elevated ABA levels, while increased ethylene emission was confined to horizontally-impeded seedlings. The trajectories of metabolomic shifts distinctly differed between vertically/horizontally-impeded roots/shoots. In horizontal roots, amino acids were the major affected group, while in vertical roots, sugars were the major group. Commonly affected metabolites in roots and shoots, trehalose, dopamine, caffeoylquinic acid, and suberic acid, hallmarked the signature for hardness. Increasing hardness lowered SnRK1a expression in roots/shoots implying regulation of metabolic homeostasis by the SnRK1 signalling module. Our data suggest that though hardness is a common denominator, roots sense the horizontal/vertical orientation and correspondingly modulate metabolite profiles.Significance statementWe show that the tomato roots sense the magnitude of hardness as well as the horizontal and vertical orientation. The hardness divergently modulates the phytohormone and metabolite levels in roots and shoots. The trajectory of the metabolic shift in vertically-grown seedling distinctly differs from horizontally-grown seedlings. ABA and trehalose were the hallmark of hardness stress and may influence metabolic alteration via the SNRK signalling pathway.

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.

scholarly journals RNA-Seq Transcriptome Analysis of Rice Primary Roots Reveals the Role of Flavonoids in Regulating the Rice Primary Root Growth

Genes ◽  
2019 ◽  
Vol 10 (3) ◽  
pp. 213
Author(s):  
Yu Xu ◽  
Junjie Zou ◽  
Hongyan Zheng ◽  
Miaoyun Xu ◽  
Xuefeng Zong ◽  
...  
Keyword(s):  
Cell Wall ◽  
Root Growth ◽  
Primary Root ◽  
Glutathione Metabolism ◽  
Auxin Signaling ◽  
Antioxidant Enzyme Activities ◽  
Rna Seq ◽  
Root Tips ◽  
Primary Roots ◽  
Quercetin Treatment

Flavonoids play important roles in root development and in its tropic responses, whereas the flavonoids-mediated changes of the global transcription levels during root growth remain unclear. Here, the global transcription changes in quercetin-treated rice primary roots were analyzed. Quercetin treatment significantly induced the inhibition of root growth and the reduction of H2O2 and O2− levels. In addition, the RNA-seq analysis revealed that there are 1243 differentially expressed genes (DEGs) identified in quercetin-treated roots, including 1032 up-regulated and 211 down-regulated genes. A gene ontology (GO) enrichment analysis showed that the enriched GO terms are mainly associated with the cell wall organization, response to oxidative stress, and response to hormone stimulus. The Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment pathway analysis showed that the enriched DEGs are involved in phenylpropanoid biosynthesis, glutathione metabolism, and plant hormone signal transduction. Moreover, the quercetin treatment led to an increase of the antioxidant enzyme activities of catalase (CAT), peroxidase (POD), and superoxide dismutase (SOD) in rice roots. Also, the quercetin treatment altered the DR5:GUS expression pattern in the root tips. All of these data indicated that the flavonoids-mediated transcription changes of genes are related to the genes involved in cell wall remodeling, redox homeostasis, and auxin signaling, leading to a reduced cell division in the meristem zone and cell elongation in the elongation zone of roots.

scholarly journals Expression Studies on AUX1-like Genes in Medicago truncatula Suggest That Auxin Is Required at Two Steps in Early Nodule Development

2001 ◽  
Vol 14 (3) ◽  
pp. 267-277 ◽  
Author(s):  
Françoise de Billy ◽  
Cathy Grosjean ◽  
Sean May ◽  
Malcolm Bennett ◽  
Julie V. Cullimore
Keyword(s):  
Medicago Truncatula ◽  
Lateral Root ◽  
Sequence Similarity ◽  
Lateral Roots ◽  
Peripheral Region ◽  
Nodule Development ◽  
Central Position ◽  
Root Tips ◽  
High Sequence Similarity ◽  
Primary Roots

Medicago truncatula contains a family of at least five genes related to AUX1 of Arabidopsis thaliana (termed MtLAX genes for Medicago truncatula-like AUX1 genes). The high sequence similarity between the encoded proteins and AUX1 implies that the MtLAX genes encode auxin import carriers. The MtLAX genes are expressed in roots and other organs, suggesting that they play pleiotropic roles related to auxin uptake. In primary roots, the MtLAX genes are expressed preferentially in the root tips, particularly in the provascular bundles and root caps. During lateral root and nodule development, the genes are expressed in the primordia, particularly in cells that were probably derived from the pericycle. At slightly later stages, the genes are expressed in the regions of the developing organs where the vasculature arises (central position for lateral roots and peripheral region for nodules). These results are consistent with MtLAX being involved in local auxin transport and suggest that auxin is required at two common stages of lateral root and nodule development: development of the primordia and differentiation of the vasculature.

GERMINATION, GROWTH AND DEVELOPMENT OF COMMON MILKWEED

1978 ◽  
Vol 58 (2) ◽  
pp. 493-498 ◽  
Author(s):  
PRASANTA C. BHOWMIK
Keyword(s):  
Lateral Roots ◽  
Seedling Emergence ◽  
Primary Root ◽  
Germination Percentage ◽  
Asclepias Syriaca ◽  
Seed Collection ◽  
Primary Roots ◽  
Number Of Leaves ◽  
Primary Root Length ◽  
Storage Temperatures

Germination percentage of common milkweed (Asclepias syriaca L.) seeds was low 1 mo after seed collection. Seed dormancy decreased with time at storage temperatures of −12°, 5° or 21 °C. After 11 months of storage, seeds stored at 21 °C had 15–18% higher germination compared to the seeds stored at −12° and 5 °C. The best seedling emergence was obtained at a temperature of 27 °C when seeds were planted at a depth of 0.5 or 1 cm. Seedling emergence was better in muck or sandy soil than in clay soil. Seedlings developed slowly up to 30 days after emergence at 15 °C under an 8-, 12- or 16-h photoperiod. High temperatures (27 °C) stimulated seedling growth under each photoperiod. Taller seedlings with more leaves, longer primary roots, more lateral roots and adventitious root buds grew at 27 °C as compared to 15° or 21 °C. Increasing the photoperiod from 8 to 16 h increased plant height and number of leaves but not primary root length.

scholarly journals Tissue growth constrains root organ outlines into an isometrically scalable shape

Development ◽  
2021 ◽  
Vol 148 (4) ◽  
pp. dev196253
Author(s):  
Motohiro Fujiwara ◽  
Tatsuaki Goh ◽  
Satoru Tsugawa ◽  
Keiji Nakajima ◽  
Hidehiro Fukaki ◽  
...  
Keyword(s):  
Plant Root ◽  
Lateral Roots ◽  
Time Lapse ◽  
Tissue Growth ◽  
Root Tip ◽  
Root Tips ◽  
Developmental Constraints ◽  
Primary Roots ◽  
Catenary Curve ◽  
Expansion Force

ABSTRACTOrgan morphologies are diverse but also conserved under shared developmental constraints among species. Any geometrical similarities in the shape behind diversity and the underlying developmental constraints remain unclear. Plant root tip outlines commonly exhibit a dome shape, which likely performs physiological functions, despite the diversity in size and cellular organization among distinct root classes and/or species. We carried out morphometric analysis of the primary roots of ten angiosperm species and of the lateral roots (LRs) of Arabidopsis, and found that each root outline was isometrically scaled onto a parameter-free catenary curve, a stable structure adopted for arch bridges. Using the physical model for bridges, we analogized that localized and spatially uniform occurrence of oriented cell division and expansion force the LR primordia (LRP) tip to form a catenary curve. These growth rules for the catenary curve were verified by tissue growth simulation of developing LRP development based on time-lapse imaging. Consistently, LRP outlines of mutants compromised in these rules were found to deviate from catenary curves. Our analyses demonstrate that physics-inspired growth rules constrain plant root tips to form isometrically scalable catenary curves.

scholarly journals Impact of soil compaction heterogeneity and moisture on maize (Zea mays L.) root and shoot development

2008 ◽  
Vol 54 (No. 12) ◽  
pp. 509-519 ◽  
Author(s):  
B. Konôpka ◽  
L. Pagès ◽  
C. Doussan
Keyword(s):  
Zea Mays ◽  
Soil Moisture ◽  
Soil Compaction ◽  
Statistical Tests ◽  
Lateral Roots ◽  
Primary Root ◽  
Leaf Biomass ◽  
Fine Soil ◽  
Primary Roots ◽  
Primary And Lateral Roots

Soil compaction heterogeneity and water content are supposed to be decisive factors influencing plant growth. Our experiment focused on simulation of two soil moisture levels (0.16 and 0.19 g/g) plus two levels of clod proportion (30 and 60% volume) and their effects on root and leaf variables of maize (<I>Zea mays</I> L.). We studied number of primary and lateral roots as well as primary root length at the particular soil depths. Statistical tests showed that the decrease rate of the number of roots versus depth was significantly affected by the two studied factors (<I>P</I> < 0.01). Soil moisture and clod occurrence, interactively, affected leaf biomass (<I>P</I> = 0.02). Presence of clods modified root morphological features. Particularly, the diameter of primary roots in the clods was significantly higher than of those grown in fine soil (<I>P</I> < 0.01). For primary roots, which penetrated clods, branching density decreased considerably for the root segments located just after the clods (<I>P</I> = 0.01). Regarding their avoidance to clods and tortuosity, large differences were found between primary roots grown in the contrasting soil environments.

scholarly journals Evaluation of Metaxylem Vessel Histogenesis and the Occurrence of Vessel Collapse during Early Development in Primary Roots of Zea mays ssp. mexicana: A Result of Premature Programmed Cell Death?

Plants ◽  
2020 ◽  
Vol 9 (3) ◽  
pp. 374
Author(s):  
Susumu Saito ◽  
Teruo Niki ◽  
Daniel K. Gladish
Keyword(s):  
Cell Death ◽  
Zea Mays ◽  
Programmed Cell Death ◽  
Primary Root ◽  
Cell Types ◽  
Root Apical Meristem ◽  
Root Tips ◽  
Primary Roots ◽  
Transmission Electron ◽  
Vessel Elements

Root apical meristem histological organization in Zea mays has been carefully studied previously. Classical histology describes its system as having a “closed organization” and a development of xylem that conforms to predictable rules. Among the first cell types to begin differentiation are late-maturing metaxylem (LMX) vessels. As part of a larger study comparing domestic maize root development to a wild subspecies of Z. mays (teosinte), we encountered a metaxylem development abnormality in a small percentage of our specimens that begged further study, as it interrupted normal maturation of LMX. Primary root tips of young seedlings of Zea mays ssp. mexicana were fixed, embedded in appropriate resins, and sectioned for light and transmission electron microscopy. Longitudinal and serial transverse sections were analyzed using computer imaging to determine the position and timing of key xylem developmental events. We observed a severe abnormality of LMX development among 3.5% of the 227 mexicana seedlings we screened. All LMX vessel elements in these abnormal roots collapsed and probably became non-functional shortly after differentiation began. Cytoplasm and nucleoplasm in the abnormal LMX elements became condensed and subdivided into irregularly-shaped “macrovesicles” as their cell walls collapsed inward. We propose that these seedlings possibly suffered from a mutation that affected the timing of the programmed cell death (PCD) that is required to produce functional xylem vessels, such that autolysis of the cytoplasm was prematurely executed, i.e., prior to the development and lignification of secondary walls.

scholarly journals Solanum lycopersicum Seedlings. Metabolic Responses Induced by the Alkamide Affinin

Metabolites ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 143
Author(s):  
Tonatiu Campos-García ◽  
Jorge Molina-Torres
Keyword(s):  
Metabolic Pathways ◽  
Lateral Roots ◽  
Primary Root ◽  
Mitochondrial Electron Transport Chain ◽  
Metabolomic Analysis ◽  
Tomato Seedlings ◽  
Relieve Pain ◽  
Transport Chain ◽  
Primary Root Length

Alkamides have been observed to interact in different ways in several superior organisms and have been used in traditional medicine in many countries e.g., to relieve pain. Previous studies showed that affinin when applied to other plant species induces prominent changes in the root architecture and induces transcriptional adjustments; however, little is known about the metabolic pathways recruited by plants in response to alkamides. Previous published work with Arabidopsis seedlings treated in vitro with affinin at 50 µM significantly reduced primary root length. In tomato seedlings, that concentration did not reduce root growth but increase the number and length of lateral roots. Non-targeted metabolomic analysis by Gas Chromatography couplet to Mass Spectrometry (GC/EIMS) showed that, in tomato seedlings, affinin increased the accumulation of several metabolites leading to an enrichment of several metabolic pathways. Affinin at 100 µM alters the accumulation of metabolites such as organic acids, amino acids, sugars, and fatty acids. Finally, our results showed a response possibly associated with nitrogen, GABA shunt and serine pathways, in addition to a possible alteration in the mitochondrial electron transport chain (ETC), interesting topics to understand the molecular and metabolic mechanisms in response to alkamide in plants.

Nitrate and glutamate sensing by plant roots

2005 ◽  
Vol 33 (1) ◽  
pp. 283-286 ◽  
Author(s):  
S. Filleur ◽  
P. Walch-Liu ◽  
Y. Gan ◽  
B.G. Forde
Keyword(s):  
Root Growth ◽  
Lateral Root ◽  
Lateral Roots ◽  
Primary Root ◽  
Root Tip ◽  
Root Tips ◽  
Environmental Signals ◽  
Specific Effects ◽  
Large Numbers ◽  
Low Concentrations

The architecture of a root system plays a major role in determining how efficiently a plant can capture water and nutrients from the soil. Growth occurs at the root tips and the process of exploring the soil volume depends on the behaviour of large numbers of individual root tips at different orders of branching. Each root tip is equipped with a battery of sensory mechanisms that enable it to respond to a range of environmental signals, including nutrients, water potential, light, gravity and touch. We have previously identified a MADS (MCM1, agamous, deficiens and SRF) box gene (ANR1) in Arabidopsis thaliana that is involved in modulating the rate of lateral root growth in response to changes in the external NO3− supply. Transgenic plants have been generated in which a constitutively expressed ANR1 protein can be post-translationally activated by treatment with dexamethasone (DEX). When roots of these lines are treated with DEX, lateral root growth is markedly stimulated but there is no effect on primary root growth, suggesting that one or more components of the regulatory pathway that operate in conjunction with ANR1 in lateral roots may be absent in the primary root tip. We have recently observed some very specific effects of low concentrations of glutamate on root growth, resulting in significant changes in root architecture. Experimental evidence suggests that this response involves the sensing of extracellular glutamate by root tip cells. We are currently investigating the possible role of plant ionotropic glutamate receptors in this sensory mechanism.

Geoperception in primary and lateral roots of Phaseolus vulgaris (Fabaceae). III. A model to explain the differential georesponsiveness of primary and lateral roots

1985 ◽  
Vol 63 (1) ◽  
pp. 21-24 ◽  
Author(s):  
J. Steven Ransom ◽  
Randy Moore
Keyword(s):  
Phaseolus Vulgaris ◽  
Concentration Gradient ◽  
Lateral Root ◽  
Lateral Roots ◽  
Primary Root ◽  
Growth Inhibitors ◽  
Gravitropic Response ◽  
Primary Roots ◽  
Primary And Lateral Roots

Half-tipped primary and lateral roots of Phaseolus vulgaris bend toward the side of the root on which the intact half tip remains. Therefore, tips of lateral and primary roots produce growth effectors capable of inducing gravicurvature. The asymmetrical placement of a tip of a lateral root onto a detipped primary root results in the root bending toward the side of the root onto which the tip was placed. That is, the lesser graviresponsiveness of lateral roots as compared with primary roots is not due to the inability of their caps to produce growth inhibitors. The more pronounced graviresponsiveness of primary roots is positively correlated with the presence of columella tissues that are 3.8 times longer, 1.7 times wider, and 10.5 times more voluminous than the columellas of lateral roots. We propose that the lack of graviresponsiveness exhibited by lateral roots is due to the facts that they (i) produce smaller amounts of the inhibitor than primary (i.e., strongly graviresponsive) roots and (ii) are unable to redistribute the inhibitor so as to be able to create a concentration gradient sufficient to induce a pronounced gravitropic response.

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