scholarly journals Reactive oxygen species signalling is involved in alkamide-induced altered root development.

2021 ◽  
Author(s):  
Tonatiu Campos García ◽  
Jorge Molina-Torres ◽  
Kirk L Overmyer
Keyword(s):  
Root Hair ◽  
Lateral Root ◽  
Root Architecture ◽  
Primary Root ◽  
Heterotrimeric G Proteins ◽  
Reverse Genetic ◽  
Transcriptional Reprogramming ◽  
Protein Mutants ◽  
Induced Changes

Alkamides are alpha unsaturated N-acylamides structurally related to N-acyl ethanolamides (NAEs) and N-acyl-L-homoserine lactones (AHLs). Studies have shown that alkamides induce prominent changes in root architecture, a significant metabolic readjustment, and transcriptional reprogramming. Some alkamide responses have been associated with redox signalling; however, this involvement and ROS sources have not been fully described. We utilized a genetic approach to address ROS signalling in alkamide-induced processes and found that in Arabidopsis, treatment with the alkamide affinin (50μM) increased the in-situ accumulation of H2O2 in lateral root emergence sites and reduced H2O2 accumulation in primary root meristems implying that altered root growth was dependent on endogenous H2O2. Results show that ROS sourced from PRX34, RBOHC and RBOHD were involved in promotion of lateral root emergence by alkamides. RBOHC was required for affinin-induced enhanced root hair expansion. Furthermore, affinin-induced changes in lateral root emergence, but not root hair length, were dependent on a change in extracellular pH. Finally, reverse genetic experiments suggest heterotrimeric G-proteins were involved in plant response to alkamides; nevertheless, further studies with additional higher order G-protein mutants will be required to resolve this question. These results support that alkamides recruit specific ROS signaling programs to mediate alterations in root architecture.

scholarly journals High throughput phenotyping of root growth dynamics, lateral root formation, root architecture and root hair development enabled by PlaRoM

2009 ◽  
Vol 36 (11) ◽  
pp. 938 ◽  
Author(s):  
Nima Yazdanbakhsh ◽  
Joachim Fisahn
Keyword(s):  
Root Growth ◽  
Growth Kinetics ◽  
Lateral Root ◽  
Root Architecture ◽  
Imaging Techniques ◽  
Plant Root ◽  
Primary Root ◽  
Growth Media ◽  
Root Extension ◽  
Lateral Root Development

Plant organ phenotyping by non-invasive video imaging techniques provides a powerful tool to assess physiological traits and biomass production. We describe here a range of applications of a recently developed plant root monitoring platform (PlaRoM). PlaRoM consists of an imaging platform and a root extension profiling software application. This platform has been developed for multi parallel recordings of root growth phenotypes of up to 50 individual seedlings over several days, with high spatial and temporal resolution. PlaRoM can investigate root extension profiles of different genotypes in various growth conditions (e.g. light protocol, temperature, growth media). In particular, we present primary root growth kinetics that was collected over several days. Furthermore, addition of 0.01% sucrose to the growth medium provided sufficient carbohydrates to maintain reduced growth rates in extended nights. Further analysis of records obtained from the imaging platform revealed that lateral root development exhibits similar growth kinetics to the primary root, but that root hairs develop in a faster rate. The compatibility of PlaRoM with currently accessible software packages for studying root architecture will be discussed. We are aiming for a global application of our collected root images to analytical tools provided in remote locations.

scholarly journals A Linear Model to Describe Branching and Allometry in Root Architecture

Plants ◽  
2019 ◽  
Vol 8 (7) ◽  
pp. 218
Author(s):  
Joel Colchado-López ◽  
R. Cristian Cervantes ◽  
Ulises Rosas
Keyword(s):  
Root Development ◽  
Lateral Root ◽  
Root Architecture ◽  
Complex Structure ◽  
Primary Root ◽  
Allometric Model ◽  
Multiple Traits ◽  
Three Stages ◽  
Natural Variations ◽  
New Feature

Root architecture is a complex structure that comprises multiple traits of the root phenotype. Novel platforms and models have been developed to better understand root architecture. In this methods paper, we introduce a novel allometric model, named rhizochron index (m), which describes lateral root (LR) branching and elongation patterns across the primary root (PR). To test our model, we obtained data from 16 natural accessions of Arabidopsis thaliana at three stages of early root development to measure conventional traits of root architecture (e.g., PR and LR length), and extracted the rhizochron index (m). In addition, we tested previously published datasets to assess the utility of the rhizochron index (m) to distinguish mutants and environmental effects on root architecture. Our results indicate that rhizochron index (m) is useful to distinguish the natural variations of root architecture between A. thaliana accessions, but not across early stages of root development. Correlation analyses in these accessions showed that m is a novel trait that partially captures information from other root architecture traits such as total lateral root length, and the ratio between lateral root and primary root lengths. Moreover, we found that the rhizochron index was useful to distinguish ABA effect on root architecture, as well as the mutant pho1 phenotype. We propose the rhizochron index (m) as a new feature of the root architectural system to be considered, in addition to conventional traits in future investigations.

scholarly journals Deep Sequencing Reveals Early Reprogramming of Arabidopsis Root Transcriptomes Upon Ralstonia solanacearum Infection

2019 ◽  
Vol 32 (7) ◽  
pp. 813-827 ◽  
Author(s):  
Cuizhu Zhao ◽  
Huijuan Wang ◽  
Yao Lu ◽  
Jinxue Hu ◽  
Ling Qu ◽  
...  
Keyword(s):  
Differentially Expressed Genes ◽  
Root Hair ◽  
Ralstonia Solanacearum ◽  
Lateral Root ◽  
Molecular Mechanisms ◽  
Temporal Dynamics ◽  
Primary Root ◽  
Differentially Expressed ◽  
Root Growth Inhibition ◽  
Successful Infection

Bacterial wilt caused by the bacterial pathogen Ralstonia solanacearum is one of the most devastating crop diseases worldwide. The molecular mechanisms controlling the early stage of R. solanacearum colonization in the root remain unknown. Aiming to better understand the mechanism of the establishment of R. solanacearum infection in root, we established four stages in the early interaction of the pathogen with Arabidopsis roots and determined the transcriptional profiles of these stages of infection. A total 2,698 genes were identified as differentially expressed genes during the initial 96 h after infection, with the majority of changes in gene expression occurring after pathogen-triggered root-hair development observed. Further analysis of differentially expressed genes indicated sequential activation of multiple hormone signaling cascades, including abscisic acid (ABA), auxin, jasmonic acid, and ethylene. Simultaneous impairment of ABA receptor genes promoted plant wilting symptoms after R. solanacearum infection but did not affect primary root growth inhibition or root-hair and lateral root formation caused by R. solanacearum. This indicated that ABA signaling positively regulates root defense to R. solanacearum. Moreover, transcriptional changes of genes involved in primary root, lateral root, and root-hair formation exhibited high temporal dynamics upon infection. Taken together, our results suggest that successful infection of R. solanacearum on roots is a highly programmed process involving in hormone crosstalk.

scholarly journals Bacillus megaterium Rhizobacteria Promote Growth and Alter Root-System Architecture Through an Auxin- and Ethylene-Independent Signaling Mechanism in Arabidopsis thaliana

2007 ◽  
Vol 20 (2) ◽  
pp. 207-217 ◽  
Author(s):  
José López-Bucio ◽  
Juan Carlos Campos-Cuevas ◽  
Erasto Hernández-Calderón ◽  
Crisanto Velásquez-Becerra ◽  
Rodolfo Farías-Rodríguez ◽  
...  
Keyword(s):  
Arabidopsis Thaliana ◽  
Root Growth ◽  
Root Hair ◽  
Lateral Root ◽  
Root Formation ◽  
Growth Promotion ◽  
Primary Root ◽  
Root System Architecture ◽  
Ethylene Signaling ◽  
Primary Root Growth

Soil microorganisms are critical players in plant-soil interactions at the rhizosphere. We have identified a Bacillus megaterium strain that promoted growth and development of bean (Phaseolus vulgaris) and Arabidopsis thaliana plants. We used Arabidopsis thaliana as a model to characterize the effects of inoculation with B. megaterium on plant-growth promotion and postembryonic root development. B. megaterium inoculation caused an inhibition in primary-root growth followed by an increase in lateral-root number, lateral-root growth, and root-hair length. Detailed cellular analyses revealed that primary root-growth inhibition was caused both by a reduction in cell elongation and by reduction of cell proliferation in the root meristem. To study the contribution of auxin and ethylene signaling pathways in the alterations in root-system architecture elicited by B. megaterium, a suite of plant hormone mutants of Arabidopsis, including aux1-7, axr4-1, eir1, etr1, ein2, and rhd6, defective in either auxin or ethylene signaling, were evaluated for their responses to inoculation with this bacteria. When inoculated, all mutant lines tested showed increased biomass production. Moreover, aux1-7 and eir1, which sustain limited root-hair and lateral-root formation when grown in uninoculated medium, were found to increase the number of lateral roots and to develop long root hairs when inoculated with B. megaterium. The ethylene-signaling mutants etr1 and ein2 showed an induction in lateral-root formation and root-hair growth in response to bacterial inoculation. Taken together, our results suggest that plant-growth promotion and root-architectural alterations by B. megaterium may involve auxin- and-ethylene independent mechanisms.

CaСl2 Salt Signaling in Primary Root Architecture and Lateral Root Emergence in Arabidopsis thaliana

2020 ◽  
Vol 67 (3) ◽  
pp. 515-520
Author(s):  
M. Nisar ◽  
Z. Ali ◽  
A. Ali ◽  
R. Aman ◽  
H. J. Park ◽  
...  
Keyword(s):  
Arabidopsis Thaliana ◽  
Lateral Root ◽  
Root Architecture ◽  
Primary Root ◽  
Salt Signaling

scholarly journals Tree Seedling Root Architecture Alteration by Tap Root Pruning1

2019 ◽  
Vol 37 (2) ◽  
pp. 50-54 ◽  
Author(s):  
Shanon Hankin ◽  
Marvin Lo ◽  
Frank Balestri ◽  
Gary Watson
Keyword(s):  
Lateral Root ◽  
Root Architecture ◽  
Lateral Roots ◽  
Primary Root ◽  
Tree Seedling ◽  
Coffee Tree ◽  
Seedling Root ◽  
Nursery Production ◽  
Taproot Pruning ◽  
The Impact

Abstract Nursery production of strong taprooted woody plants typically includes pruning to interrupt taproot development. To discern the impact this practice could have on seedling root architecture, we quantified changes to root architecture after taproot pruning and restriction separately in Catalpa (Catalpa speciosa) and Kentucky coffee tree (Gymnocladus dioicus). Taproot pruning resulted in a large and significant increase in the number of new, vertically oriented roots from the cut end of the primary root (regenerated taproots) in both species. Catalpa seedlings, which produced many strong laterals on unpruned taproots, showed greater reduction in lateral root number and size after taproot pruning than Kentucky coffee tree (with fewer and smaller natural lateral roots). The two species responded differently to restriction of the single, unpruned taproot by container depth (15, 30, 60 cm). For catalpa, with more shallow laterals naturally, the number of laterals was not significantly changed by restriction of the taproot by air pruning at any container depth, but lateral diameter was reduced by the 15 cm-deep container and biomass was reduced by the 30 cm-deep container, compared to the 60 cm-deep container. For Kentucky coffee tree with fewer natural laterals, restricting the taproot at 15 cm significantly increased the number and diameter of lateral roots compared to the 30 and 60 cm-deep containers, suggesting that restricting the taproot could increase the number of laterals in species that naturally produce fewer. Restricting multiple taproots on root-pruned plants generally did not affect lateral root development for either species, but this may have been due to the low number of lateral roots on those root systems. Index words: root architecture, nursery production, urban soils Species used in this study: Catalpa [Catalpa speciosa (Warder) Warder ex Engelm. ]; Kentucky coffee tree [Gymnocladus dioicus (L.) K. Koch]

scholarly journals Tornado1 and tornado2 are required for the specification of radial and circumferential pattern in the Arabidopsis root

Development ◽  
2000 ◽  
Vol 127 (15) ◽  
pp. 3385-3394
Author(s):  
G. Cnops ◽  
X. Wang ◽  
P. Linstead ◽  
M. Van Montagu ◽  
M. Van Lijsebettens ◽  
...  
Keyword(s):  
Root Hair ◽  
Lateral Root ◽  
Cell Function ◽  
Primary Root ◽  
Root Cap ◽  
Radial Pattern ◽  
Root Hair Cell ◽  
Cell Layers ◽  
Default State ◽  
Hair Cell Differentiation

The cell layers of the Arabidopsis primary root are arranged in a simple radial pattern. The outermost layer is the lateral root cap and lies outside the epidermis that surrounds the ground tissue. The files of epidermal and lateral root cap cells converge on a ring of initials (lateral root cap/epidermis initial) from which the epidermal and lateral root cap tissues of the seedling are derived, once root growth is initiated after germination. Each initial gives rise to a clone of epidermal cells and a clone of lateral root cap cells. These initial divisions in the epidermal/lateral root cap initial are defective in tornado1 (trn1) and trn2 plants indicating a requirement for TRN1 and TRN2 for initial cell function. Furthermore, lateral root cap cells develop in the epidermal position in trn1 and trn2 roots indicating that TRN1 and TRN2 are required for the maintenance of the radial pattern of cell specification in the root. The death of these ectopic lateral root cap cells in the elongation zone (where lateral root cap cells normally die) results in the development of gaps in the epidermis. These observations indicate that TRN1 and TRN2 are required to maintain the distinction between the lateral root cap and epidermis and suggest that lateral root cap fate is the default state. It also suggests that TRN1 and TRN2 repress lateral root cap fate in cells in the epidermal location. Furthermore, the position-dependent pattern of root hair and non-root hair cell differentiation in the epidermis is defective in trn1 and trn2 mutants. Together these results indicate that TRN1 and TRN2 are required for the maintenance of both the radial pattern of tissue differentiation in the root and for the subsequent circumferential pattern within the epidermis.

scholarly journals Malate content of picoliter samples of Raphanus sativus cytoplasm.

1991 ◽  
Vol 39 (4) ◽  
pp. 435-440 ◽  
Author(s):  
M J Bodson ◽  
W H Outlaw ◽  
S H Silvers
Keyword(s):  
Root Hair ◽  
Phosphoenolpyruvate Carboxylase ◽  
Raphanus Sativus ◽  
Organic Anion ◽  
Root Hairs ◽  
Interactive Effects ◽  
Plant Metabolism ◽  
Individual Root

Malate, which plays many essential roles in plant metabolism, is a potent in vitro inhibitor of the cytosolic enzyme phosphoenolpyruvate carboxylase (PEPC). Because PEPC activity leads to malate biosynthesis, malate is assumed to attenuate its own synthesis in situ. To test this hypothesis, we measured directly the malate content of picoliter samples of Raphanus root-hair cytoplasm using quantitative histochemical techniques. We also obtained an estimate for malate accumulation in these cells. These values were compared with the PEPC activity of individual root hairs (less than 2 ng). The results indicate that high cytoplasmic malate concentration does not severely inhibit PEPC in situ. We suggest that the focus for studies on the regulation of organic anion accumulation be on the interactive effects of malate and other PEPC effectors.

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