scholarly journals 486 Expression of β-glucuronidase Gene in Aspen under Control of CaMV35S, Heat Shock and RolC Promoters

HortScience ◽  
2000 ◽  
Vol 35 (3) ◽  
pp. 478A-478
Author(s):  
Wenhao Dai ◽  
Zong-Ming Cheng ◽  
Wayne Sargent
Keyword(s):  
Heat Shock ◽  
Apical Meristem ◽  
Gus Activity ◽  
Root Apical Meristem ◽  
Blue Staining ◽  
Root Tip ◽  
Growth Stages ◽  
Gus Gene ◽  
Heat Shock Promoter ◽  
Strong Expression

Transgenic hybrid aspens (Populus tremuloides × P. tremula) were produced by Agrobacterium-mediated transformation and confirmed by polymerase chain reaction. Three promoters (CaMV 35S, Heat shock, and Rol C) were used to drive transcription of chimeric genes -glucuronidase (GUS), npt-II, and rol B. Stem sections in ≈100 mm thick, leaf blades, and root tips of transgenic aspen were treated with X-Gluc solution for 2 to 12 h in a 37 °C incubator and fixed in a solution containing 5% formaldehyde, 5% acetic acid, and 20% ethanol (FAA) for 10 min. After washing with 50% ethanol twice and clearing with absolute ethanol until free of chlorophyll, the GUS expression (localization and intensity of blue staining) in leaf, stem, and root at different growth stages were evaluated and photographed under the light microscope. When CaMV35S and rol C were used as promoters, the GUS gene was expressed in all parts of mature stem except pith, with the strongest activity in phloem. The heat shock promoter gave rise to very strong expression only in epidermis and phloem. In the young stem, GUS activity was detected in epidermis, parenchyma, vascular cambium, and primary xylem in CaMV35S-GUS transformed aspen shoots. The rol C promoter produced GUS gene expression in all stem tissues. When the heat shock promoter was used, the GUS gene expressed in a more tissue-specific manner, especially in mature stems, with activity mainly in parenchyma. In young leaf tissues, the GUS activity was primarily located in veins and mesophyll. In the mature leaves, no blue staining was found in the main vein. In root tip, the GUS gene driven by CaMV35S and heat shock promoters were expressed in the columella, vascular, and root apical meristem with very strong expression in the root apical meristem. Aspen plants transformed by rol C-Gus construct showed less or no expression in the columella.

scholarly journals Analysis of the rrl3 Mutants Reveals the Importance of Arginine Biosynthesis in the Maintenance of Root Apical Meristem in Rice

2017 ◽  
Vol 7 (1) ◽  
pp. 36
Author(s):  
Israt J. Shelley ◽  
Sayaka Watanabe ◽  
Hiroaki Ozaki ◽  
Nobuhiro Nagasawa ◽  
Atsushi Ogawa ◽  
...  
Keyword(s):  
Apical Meristem ◽  
Culture Medium ◽  
Root Apical Meristem ◽  
Root Tip ◽  
Quiescent Center ◽  
Carbamoyl Phosphate Synthetase ◽  
Arginine Biosynthesis ◽  
Carbamoyl Phosphate ◽  
Short Root ◽  
Spatiotemporal Expression

We characterized reduced root length3(rrl3) mutantsof rice that exhibit a short-root phenotype under conditions producing mechanical impediments to growth, such as aerated water culture medium. The mutants were not able to maintain the quiescent center (QC) identity and produced disorganized root apical meristem (RAM) under aeration because of impaired cell division. A map-based cloning approach showed that RRL3 encodes carbamoyl phosphate synthetase (CPS) which is thought to be required for the conversion of ornithine into citrulline during arginine biosynthesis. The RRL3 gene is expressed highly at the root tip area that includes the root cap and division zone. The RRL3 gene expression level was greatly affected by aeration treatment, indicating that the spatiotemporal expression of the RRL3 gene with respect to the aeration is important for the maintenance of RAM. Furthermore, the application of citrulline and arginine could rescue the root phenotype, which implied that arginine biosynthesis was impaired in the rrl3-1 mutant. These results suggest that the RRL3 regulated arginine biosynthesis is important for the maintenance of RAM organization in the presence of mechanical impediments. 

scholarly journals A 3D digital atlas of the Nicotiana tabacum root tip and its use to investigate changes in the root apical meristem induced by the Agrobacterium 6b oncogene

2017 ◽  
Vol 92 (1) ◽  
pp. 31-42 ◽  
Author(s):  
Taras Pasternak ◽  
Thomas Haser ◽  
Thorsten Falk ◽  
Olaf Ronneberger ◽  
Klaus Palme ◽  
...  
Keyword(s):  
Nicotiana Tabacum ◽  
Apical Meristem ◽  
Root Apical Meristem ◽  
Root Tip ◽  
Digital Atlas

scholarly journals Glutathione Enhances Auxin Sensitivity in Arabidopsis Roots

Biomolecules ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 1550
Author(s):  
Taras Pasternak ◽  
Klaus Palme ◽  
Ivan A. Paponov
Keyword(s):  
Transcriptional Activation ◽  
Apical Meristem ◽  
Molecular Mechanisms ◽  
Transcriptional Response ◽  
Buthionine Sulfoximine ◽  
Root Apical Meristem ◽  
Root Tip ◽  
Root Growth Inhibition ◽  
Auxin Response ◽  
Auxin Concentration

Root development is regulated by the tripeptide glutathione (GSH), a strong non-enzymatic antioxidant found in plants but with a poorly understood function in roots. Here, Arabidopsis mutants deficient in GSH biosynthesis (cad2, rax1, and rml1) and plants treated with the GSH biosynthesis inhibitor buthionine sulfoximine (BSO) showed root growth inhibition, significant alterations in the root apical meristem (RAM) structure (length and cell division), and defects in lateral root formation. Investigation of the molecular mechanisms of GSH action showed that GSH deficiency modulated total ubiquitination of proteins and inhibited the auxin-related, ubiquitination-dependent degradation of Aux/IAA proteins and the transcriptional activation of early auxin-responsive genes. However, the DR5 auxin transcriptional response differed in root apical meristem (RAM) and pericycle cells. The RAM DR5 signal was increased due to the up-regulation of the auxin biosynthesis TAA1 protein and down-regulation of PIN4 and PIN2, which can act as auxin sinks in the root tip. The transcription auxin response (the DR5 signal and expression of auxin responsive genes) in isolated roots, induced by a low (0.1 µM) auxin concentration, was blocked following GSH depletion of the roots by BSO treatment. A higher auxin concentration (0.5 µM) offset this GSH deficiency effect on DR5 expression, indicating that GSH deficiency does not completely block the transcriptional auxin response, but decreases its sensitivity. The ROS regulation of GSH, the active GSH role in cell proliferation, and GSH cross-talk with auxin assume a potential role for GSH in the modulation of root architecture under stress conditions.

scholarly journals Malate-dependent Fe accumulation is a critical checkpoint in the root developmental response to low phosphate

2016 ◽  
Author(s):  
Javier Mora-Macías ◽  
Jonathan Odilón Ojeda-Rivera ◽  
Dolores Gutiérrez-Alanís ◽  
Lenin Yong-Villalobos ◽  
Araceli Oropeza-Aburto ◽  
...  
Keyword(s):  
Crop Production ◽  
Apical Meristem ◽  
Root System Architecture ◽  
Root Apical Meristem ◽  
Root Tip ◽  
Short Root ◽  
Agricultural Ecosystems ◽  
Developmental Program ◽  
Pi Starvation ◽  
Malate Transporter

AbstractLow phosphate (Pi) availability constrains plant development and crop production in both natural and agricultural ecosystems. When Pi is scarce, modifications of root system architecture (RSA) enhance soil exploration ability and can lead to an increase in Pi uptake. In Arabidopsis, an iron-dependent determinate developmental program that induces premature differentiation in the root apical meristem (RAM) begins when the root tip contacts low Pi media, resulting in a short-root phenotype. However, the mechanisms that enable the regulation of root growth in response to Pi-limiting conditions remain largely unknown. Cellular, genomic and transcriptomic analysis of low-Pi insensitive mutants revealed that the malate-exudation related genes SENSITIVE TO PROTON RHIZOTOXICITY (STOP1) and ALUMINUM ACTIVATED MALATE TRANSPORTER 1 (ALMT1) represent a critical checkpoint in the root developmental response to Pi starvation in Arabidopsis thaliana.

Critical level of radiation damage of root apical meristem and mechanisms for its recovery in Pisum sativum L.

2011 ◽  
Vol 45 (1) ◽  
pp. 18-26 ◽  
Author(s):  
E. A. Kravets ◽  
A. N. Mikheev ◽  
L. G. Ovsyannikova ◽  
D. M. Grodzinsky
Keyword(s):  
Pisum Sativum ◽  
Radiation Damage ◽  
Apical Meristem ◽  
Critical Level ◽  
Root Apical Meristem ◽  
Pisum Sativum L

scholarly journals Sound Waves Promote Arabidopsis thaliana Root Growth by Regulating Root Phytohormone Content

2021 ◽  
Vol 22 (11) ◽  
pp. 5739
Author(s):  
Joo Yeol Kim ◽  
Hyo-Jun Lee ◽  
Jin A Kim ◽  
Mi-Jeong Jeong
Keyword(s):  
Arabidopsis Thaliana ◽  
Cell Division ◽  
Root Growth ◽  
Apical Meristem ◽  
Cell Number ◽  
Root Apical Meristem ◽  
Control Group ◽  
Auxin Signaling ◽  
Ethylene Signaling ◽  
Sound Waves

Sound waves affect plants at the biochemical, physical, and genetic levels. However, the mechanisms by which plants respond to sound waves are largely unknown. Therefore, the aim of this study was to examine the effect of sound waves on Arabidopsis thaliana growth. The results of the study showed that Arabidopsis seeds exposed to sound waves (100 and 100 + 9k Hz) for 15 h per day for 3 day had significantly longer root growth than that in the control group. The root length and cell number in the root apical meristem were significantly affected by sound waves. Furthermore, genes involved in cell division were upregulated in seedlings exposed to sound waves. Root development was affected by the concentration and activity of some phytohormones, including cytokinin and auxin. Analysis of the expression levels of genes regulating cytokinin and auxin biosynthesis and signaling showed that cytokinin and ethylene signaling genes were downregulated, while auxin signaling and biosynthesis genes were upregulated in Arabidopsis exposed to sound waves. Additionally, the cytokinin and auxin concentrations of the roots of Arabidopsis plants increased and decreased, respectively, after exposure to sound waves. Our findings suggest that sound waves are potential agricultural tools for improving crop growth performance.

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 Genome-wide investigation of heat shock transcription factor family in wheat (Triticum aestivum L.)

2019 ◽  
Author(s):  
Jiali Ye ◽  
Xuetong Yang ◽  
Sha Li ◽  
Wei Li ◽  
Qi Liu ◽  
...  
Keyword(s):  
Heat Shock ◽  
Reference Genome ◽  
Phylogenetic Analyses ◽  
Triticum Aestivum L ◽  
Growth Stages ◽  
Rna Seq ◽  
Male Sterile ◽  
Heat Shock Transcription Factors ◽  
Genome Wide ◽  
Resistance To Heat

Abstract Background: Heat shock transcription factors (HSFs) play crucial roles in resisting heat stress and regulating plant development. Investigating the HSF family is essential for understanding the fertility conversion mechanism in thermo-sensitive male sterile wheat. Previous studies have investigated the HSF family in wheat but it is necessary to conduct more in-depth and systematic analyses based on the newly published reference genome. Results: In the present study, 61 wheat Hsf (TaHsf) genes were identified using two main strategies and renamed based on their physical locations on chromosomes. According to the gene structure and phylogenetic analyses, the 61 TaHsf genes were classified into three categories and eleven subclasses. The genes were unequally distributed on 21 chromosomes, including two pairs of tandem duplication genes and 52 TaHsf segmental duplication genes. According to the cis-elements identified, most of the TaHsfs can be activated by Ca++ and MYB, and they respond to drought, light, copper, and other stresses as well as heat shock. RNA-seq analysis indicated that the A2 class TaHsf genes exhibited persistently upregulated expression levels in the leaves/shoots, roots (except in the vegetative growth and reproductive growth stages), spikes, and grains in wheat under normal conditions. The A and B class TaHsf genes were positively regulated during the resistance to heat, whereas the C class genes were involved in drought regulation in wheat. Only the A and B class TaHsf genes were upregulated under fertile conditions in thermo-sensitive male sterile wheat. Conclusion: In this study, 61 wheat Hsf genes were identified based on the complete wheat reference genome. This comprehensive analysis provides novel insights into the TaHsf genes, including their diverse functions and involvement in metabolic pathways.

Primary vascular patterns in root meristems of Pontederia cordata and their relevance to studies of root development

1980 ◽  
Vol 58 (12) ◽  
pp. 1351-1369 ◽  
Author(s):  
W. A. Charlton
Keyword(s):  
Apical Meristem ◽  
Vascular System ◽  
Root Apex ◽  
Root Apical Meristem ◽  
Vascular Pattern ◽  
Quiescent Centre ◽  
Vascular Differentiation ◽  
Pontederia Cordata ◽  
Distribution Of Components ◽  
Root Apices

There are several files of metaxylem cells in root apices of Pontederia cordata L., each considered to consist of a series of prospective vessels with their ends in contact. Two longitudinally adjacent vessels may be in the same file of cells produced by the root apex or in adjacent files. As the root grows, successive prospective vessels are added to the apical ends of most of the files but not all files are continued. Addition of prospective vessels appears to take place within the "quiescent centre" of the root apical meristem. Where files are not continued there is no immediate readjustment of remaining files. The longitudinal and transverse distribution of components of the vascular system (including protophloem and protoxylem) is discussed in relation to the means by which the pattern of development may be controlled. Rates of production of vessels and the final lengths of the vessels are estimated. The observations and deductions are discussed in relation to other studies of root growth, vascular differentiation, and vascular pattern formation and maintenance.

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