Effect of aluminium on membrane potential and ion fluxes at the apices of wheat roots

Aluminium (Al) tolerance in wheat (Triticum aestivum L.) is associated with the Al-activated efflux of malate and K+ from the root apices. We tested the hypothesis that these Al-activated ion fluxes would induce changes in the membrane potential (Vm) and that these responses would differ between wheat genotypes that differ in Al tolerance. Within minutes of exposing wheat roots to 50 μm AlCl3, a significant depolarisation was measured in the Al-tolerant ET8 genotype but not in a near-isogenic, Al-sensitive genotype, ES8. We investigated the ion movements that may be responsible for these changes in Vm by measuring real-time fluxes of Cl–, H+ and K+ at the root apices of wheat seedlings using the non-invasive microelectrode ion flux estimation (MIFE) technique. Addition of 50 μm AlCl3 to the bathing solution stimulated an increase in K+ efflux and H+ influx in ET8 but not in ES8. The differences between the genotypes were sustained for 24 h and were observed only at the elongating zone and not the meristematic zone. After 24 h Al increased Cl– influx in ET8 but inhibited ES8 influx in a dose-dependent manner. These results provide new temporal and spatial information on the Al-activated ion fluxes from intact wheat plants.

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Effect of 24-epibrassinolide on localization of ABA, AZP, and dehydrins in wheat plant roots during dehydration

Biomics ◽

10.31301/2221-6197.bmcs.2020-20 ◽

2020 ◽

Vol 12 (3) ◽

pp. 329-336

Author(s):

A.R. Lubyanova ◽

F.M. Shakirova ◽

M.V. Bezrukova

Keyword(s):

Triticum Aestivum ◽

Wheat Germ ◽

Wheat Plant ◽

Triticum Aestivum L ◽

Immunohistochemical Localization ◽

Plant Roots ◽

Wheat Roots ◽

Wheat Seedlings ◽

Apoplastic Barrier ◽

Protective Proteins

We studied the immunohistochemical localization of abscisic acid (ABA), wheat germ agglutinin (WGA) and dehydrins in the roots of wheat seedlings (Triticum aestivum L.) during 24-epibrassinolide-pretreatment (EB-pretreatment) and PEG-induced dehydration. It was found coimmunolocalization of ABA, WGA and dehydrins in the cells of central cylinder of basal part untreated and EB-pretreated roots of wheat seedlings under normal conditions and under osmotic stress. Such mutual localization ABA and protective proteins, WGA and dehydrins, indicates the possible effect of their distribution in the tissues of EB-pretreated wheat roots during dehydration on the apoplastic barrier functioning, which apparently contributes to decrease the water loss under dehydration. Perhaps, the significant localization of ABA and wheat lectin in the metaxylem region enhances EB-induced transport of ABA and WGA from roots to shoots under stress. It can be assumed that brassinosteroids can serve as intermediates in the realization of the protective effect of WGA and wheat dehydrins during water deficit.

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Changes in the Ultrastructure of the Root Tip of Wheat Following Exposure to Aluminium

Functional Plant Biology ◽

10.1071/pp9940085 ◽

1994 ◽

Vol 21 (1) ◽

pp. 85 ◽

Cited By ~ 11

Author(s):

MLD Lima ◽

L Copeland

Keyword(s):

Triticum Aestivum ◽

Prolonged Exposure ◽

Morphological Changes ◽

Triticum Aestivum L ◽

Root Tip ◽

Cortical Layers ◽

Wheat Roots ◽

Wheat Seedlings ◽

Meristematic Cells ◽

Fermentative Metabolism

Investigations have been carried out on morphological changes induced by aluminium ions in roots of wheat seedlings (Triticum aestivum L. cv. Vulcan). Lesions were evident on the surface of the roots after 4-8 h of exposure, and within 24 h there was increased vacuolation, loss of turgor, and severe cytoplasmic disorganisation in epidermal and peripheral cap cells. The central cap and cortical layers were also severely damaged by aluminium, but changes in the meristematic cells became evident only after more prolonged exposure of roots to aluminium. Mobilisation of starch in amyloplasts of peripheral and central cap cells of aluminium-stressed roots was particularly noticeable, and this was accompanied by an increase in the amount of extractable activity of starch-degrading enzymes. The possibility that the mobilisation of starch is linked to a coincident increase in fermentative metabolism in Al-stressed wheat roots is considered.

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Transcriptome analysis of osmotic-responsive genes in ABA-dependent and -independent pathways in wheat (Triticum aestivum L.) roots

PeerJ ◽

10.7717/peerj.6519 ◽

2019 ◽

Vol 7 ◽

pp. e6519 ◽

Cited By ~ 2

Author(s):

Chunxi Li ◽

Wenli Zhang ◽

Meng Yuan ◽

Lina Jiang ◽

Bo Sun ◽

...

Keyword(s):

Osmotic Stress ◽

Calcium Binding ◽

Molecular Mechanisms ◽

Soluble Sugars ◽

Triticum Aestivum L ◽

Wheat Roots ◽

Wheat Growth ◽

Wheat Seedlings ◽

Yield And Quality ◽

Trehalose Biosynthesis

Bread wheat is one of the most important crops in the world. However, osmotic stress significantly inhibits wheat growth and development, and reduces crop yield and quality. Plants respond to osmotic stress mainly through abscisic acid (ABA)-dependent and -independent pathways. In this study, root transcriptome profiles of wheat seedlings exposed to osmotic stress and exogenous ABA were analysed to identify osmotic-responsive genes belonging to the ABA-dependent or -independent pathways. We found that osmotic stress promoted proline biosynthesis in the ABA-dependent pathway, and trehalose biosynthesis is likely promoted among soluble sugars to maintain protein bioactivity under osmotic stress. In wheat roots subjected to osmotic stress, calcium ions, and glutathione exert their functions mainly through calcium-binding protein (CaM/CML) and glutathione-S-transferase, respectively, depending on both pathways. In addition, a complex relationship among phytohormones signal transduction was observed in response to osmotic stress. The findings of this study deepen our understanding of the molecular mechanisms of osmotic-stress resistance, and provide several candidate osmotic-responsive genes for further study.

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Malate Efflux From Root Apices and Tolerance to Aluminium Are Highly Correlated in Wheat

Functional Plant Biology ◽

10.1071/pp9950531 ◽

1995 ◽

Vol 22 (4) ◽

pp. 531 ◽

Cited By ~ 123

Author(s):

PR Ryan ◽

E Delhaize ◽

PJ Randall

Keyword(s):

Root Growth ◽

Triticum Aestivum L ◽

General Mechanism ◽

Al Tolerance ◽

Relative Tolerance ◽

Relative Root Growth ◽

Highly Correlated ◽

Root Apices ◽

Relative Root ◽

Sensitive Genotype

Aluminium (Al) can stimulate the efflux of malate and other organic acids from root apices of wheat (Triticum aestivum L.) seedlings. This response has been implicated in a mechanism of Al tolerance since the amount of malate released from an Al-tolerant genotype was 5-10-fold greater than the amount released from a near-isogenic, but Al sensitive, genotype. In the present study, 36 wheat cultivars were screened for Al tolerance and for the amount of malate released from their root apices with a standard A1 treatment. Excised root apices (3.0 mm) were used to measure malate efflux, and the relative tolerance to Al was determined from root growth measurements in 3 and 10μM AlCl3 with 200 μM CaCl2, pH 4.3. There was a significant correlation between relative tolerance of the genotypes to Al and the amount of malate released from their root apices. Growth measurements were also used to investigate the amelioration of Al toxicity by exogenous malate. In the presence of 3 μM Al alone, relative root growth of an Al-sensitive genotype was reduced to 13% of the control. Addition of 10 μM malate to the solution increased relative root growth to 50%, and 20 �M malate completely alleviated the Al-induced inhibition of root growth. The results support the hypothesis that the Al-stimulated efflux of malate from root apices is involved in a general mechanism for Al tolerance in wheat.

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Glycine Betaine-Mediated Root Priming Improves Water Stress Tolerance in Wheat (Triticum aestivum L.)

Agriculture ◽

10.3390/agriculture11111127 ◽

2021 ◽

Vol 11 (11) ◽

pp. 1127

Author(s):

Nazir Ahmed ◽

Mingyuan Zhu ◽

Qiuxia Li ◽

Xilei Wang ◽

Jiachi Wan ◽

...

Keyword(s):

Triticum Aestivum ◽

Water Stress ◽

Stress Tolerance ◽

Root Architecture ◽

Dry Matter ◽

Triticum Aestivum L ◽

Dry Matter Accumulation ◽

Wheat Roots ◽

Wheat Seedlings ◽

Water Stress Tolerance

Droughts represent one of the main challenges that climate change imposes on crop production. As a globally cultivated staple crop, wheat (Triticum aestivum L.) is prone to drought environments. Therefore, improvement in drought tolerance represents a growing concern to ensure food security, especially for wheat. In this perspective, the application of Phyto-phillic exogenous materials such as glycine-betaine (GB) has been attracting attention, particularly in stress-related studies. Since roots procure the water and nutrients for plants, any improvements in their response and capacity against drought stress could induce stress tolerance in plants. However, the knowledge about the changes in root architecture, defense mechanism, hormonal metabolism, and downstream signaling, in response to GB-mediated root priming, is still limited. Therefore, we designed the present study to investigate the role of GB-mediated root priming in improving the water stress tolerance in wheat (cv. Jimai-22) under in-vitro conditions. The roots of twelve days old wheat seedlings were treated with Hoagland’s solution (GB-0), 50 mM GB (GB-1), and 100 mM GB (GB-2) for 48 h and subjected to well-watered (WW) and water-stress (WS) conditions. The osmotic stress substantially impaired shoot/root growth, dry matter accumulation, and increased malondialdehyde (MDA) and hydrogen-peroxide (H2O2) production in the roots of wheat seedlings. However, GB-mediated root priming improved the redox homeostasis of wheat roots by boosting the activities of SOD and POD and triggering the significantly higher accumulation of abscisic acid (ABA) and salicylic acid (SA) in the roots of GB-primed plants. Consequently, it modified the root architecture system and improved plant growth, dry matter accumulation, and water-stress tolerance of wheat seedlings. Moreover, GB-mediated root priming increased root sensitivity to water stress and induced overexpression of stress-responsive genes involved in ABA metabolism (TaNECD1, TaABA’OH2), their downstream signal transduction (TaPP2C, TaSNRK2.8), and activation of different transcriptional factors (TabZIP60, TaAREB3, TaWRKY2, TaERF3, and TaMYB3) that are associated with plant metabolite accumulation and detoxification of ROS under water stress conditions. Overall, our results demonstrated that GB-priming improved the physiological and biochemical attributes of wheat plants under WS conditions by improving the drought perception capacity of wheat roots, ultimately enhancing the water stress tolerance. Thus, the GB-priming of roots could help to enhance the water-stress tolerance of economically important crops (i.e., wheat).

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Synthesis and Biological Evaluation of Novel Heterocyclic Imines Linked Coumarin- Thiazole Hybrids as Anticancer Agents

Anti-Cancer Agents in Medicinal Chemistry ◽

10.2174/1871520619666190207140120 ◽

2019 ◽

Vol 19 (4) ◽

pp. 557-566 ◽

Cited By ~ 7

Author(s):

Nerella S. Goud ◽

Mahammad S. Ghouse ◽

Jatoth Vishnu ◽

Jakkula Pranay ◽

Ravi Alvala ◽

...

Keyword(s):

Cell Cycle ◽

Membrane Potential ◽

Fluorescence Spectroscopy ◽

Mitochondrial Membrane Potential ◽

Mitochondrial Membrane ◽

Annexin V ◽

Biological Evaluation ◽

Dependent Manner ◽

Dapi Staining ◽

Dose Dependent

Background: Human Galectin-1, a protein of lectin family showing affinity towards β-galactosides has emerged as a critical regulator of tumor progression and metastasis, by modulating diverse biological events including homotypic cell aggregation, migration, apoptosis, angiogenesis and immune escape. Therefore, galectin-1 inhibitors might represent novel therapeutic agents for cancer. Methods: A new series of heterocyclic imines linked coumarin-thiazole hybrids (6a-6r) was synthesized and evaluated for its cytotoxic potential against a panel of six human cancer cell lines namely, lung (A549), prostate (DU-145), breast (MCF-7 & MDA-MB-231), colon (HCT-15 & HT-29) using MTT assay. Characteristic apoptotic assays like DAPI staining, cell cycle, annexin V and Mitochondrial membrane potential studies were performed for the most active compound. Furthermore, Gal-1 inhibition was confirmed by ELISA and fluorescence spectroscopy. Results: Among all, compound 6g 3-(2-(2-(pyridin-2-ylmethylene) hydrazineyl) thiazol-4-yl)-2H-chromen-2- one exhibited promising growth inhibition against HCT-15 colorectal cancer cells with an IC50 value of 1.28 ± 0.14 µM. The characteristic apoptotic morphological features like chromatin condensation, membrane blebbing and apoptotic body formation were clearly observed with compound 6g on HCT-15 cells using DAPI staining studies. Further, annexin V-FITC/PI assay confirmed effective early apoptosis induction by treatment with compound 6g. Loss of mitochondrial membrane potential and enhanced ROS generation were confirmed with JC-1 and DCFDA staining method, respectively by treatment with compound 6g, suggesting a possible mechanism for inducing apoptosis. Moreover, flow cytometric analysis revealed that compound 6g blocked G0/G1 phase of the cell cycle in a dose-dependent manner. Compound 6g effectively reduced the levels of Gal-1 protein in a dose-dependent manner. The binding constant (Ka) of 6g with Gal-1 was calculated from the intercept value which was observed as 1.9 x 107 M-1 by Fluorescence spectroscopy. Molecular docking studies showed strong interactions of compound 6g with Gal-1 protein. Conclusion: Our studies demonstrate the anticancer potential and Gal-1 inhibition of heterocyclic imines linked coumarin-thiazole hybrids.

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Grape Seed Proanthocyanidins Protect N2a Cells against Ischemic Injury via Endoplasmic Reticulum Stress and Mitochondrial-associated Pathways

CNS & Neurological Disorders - Drug Targets ◽

10.2174/1871527318666190212111650 ◽

2019 ◽

Vol 18 (4) ◽

pp. 334-341 ◽

Cited By ~ 3

Author(s):

Kun Fu ◽

Liqiang Chen ◽

Lifeng Miao ◽

Yan Guo ◽

Wei Zhang ◽

...

Keyword(s):

Membrane Potential ◽

Cell Viability ◽

Mitochondrial Membrane Potential ◽

Mitochondrial Membrane ◽

Grape Seed ◽

Mrna Levels ◽

Dependent Manner ◽

Grape Seed Proanthocyanidins ◽

N2a Cells ◽

Caspase 12

Background/Objective: Grape seed proanthocyanidins (GSPs) are a group of polyphenolic bioflavonoids, which possess a variety of biological functions and pharmacological properties. We studied the neuroprotective effects of GSP against oxygen-glucose deprivation/reoxygenation (OGD/R) injury and the potential mechanisms in mouse neuroblastoma N2a cells. Methods: OGD/R was conducted in N2a cells. Cell viability was evaluated by CCK-8 and LDH release assay. Apoptosis was assessed by TUNEL staining and flow cytometry. Protein levels of cleaved caspase-3, Bax and Bcl-2 were detected by Western blotting. CHOP, GRP78 and caspase-12 mRNA levels were assessed by real-time PCR. JC-1 dying was used to detect mitochondrial membrane potential. ROS levels, activities of endogenous antioxidant enzymes and ATP production were examined to evaluate mitochondrial function. Results: GSP increased cell viability after OGD/R injury in a dose-dependent manner. Furthermore, GSP inhibited cell apoptosis, reduced the mRNA levels of CHOP, GRP78 and caspase-12 (ER stressassociated genes), restored mitochondrial membrane potential and ATP generation, improved activities of endogenous anti-oxidant ability (T-AOC, GXH-Px, and SOD), and decreased ROS level. Conclusion: Our findings suggest that GSP can protect N2a cells from OGD/R insult. The mechanism of anti-apoptotic effects of GSP may involve attenuating ER stress and mitochondrial dysfunction.

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Remodeling of root morphology by CuO and ZnO nanoparticles: effects on drought tolerance for plants colonized by a beneficial pseudomonad

Botany ◽

10.1139/cjb-2017-0124 ◽

2018 ◽

Vol 96 (3) ◽

pp. 175-186 ◽

Cited By ~ 11

Author(s):

Kwang-Yeol Yang ◽

Stephanie Doxey ◽

Joan E. McLean ◽

David Britt ◽

Andre Watson ◽

...

Keyword(s):

Calcareous Soils ◽

Root Hairs ◽

Triticum Aestivum L ◽

Metal Stress ◽

Root Tip ◽

Zno Nps ◽

Wheat Seedlings ◽

Cuo Nps ◽

Expression Of Genes ◽

Induced Tolerance

Formulations that include nanoparticles of CuO and ZnO are being considered for agricultural applications as fertilizers because they act as sources of Cu or Zn. Currently, few studies of the effects of these nanoparticles (NPs) consider the three-way interactions of NPs with the plant plus its microbiome. At doses that produced root shortening by both nanoparticles (NPs), CuO NPs induced the proliferation of elongated root hairs close to the root tip, and ZnO NPs increased lateral root formation in wheat seedlings (Triticum aestivum L.). These responses occurred with roots colonized by a beneficial bacterium, Pseudomonas chlororaphis O6 (PcO6), originally isolated from roots of wheat grown under dryland farming in calcareous soils. The PcO6-induced tolerance to drought stress in wheat seedlings was not impaired by the NPs. Rather, growth of the PcO6-colonized plants with NPs resulted in systemic increases in the expression of genes associated with tolerance to water stress. Increased expression in the shoots of other genes related to metal stress was consistent with higher levels of Cu and Zn in PcO6-colonized shoots grown with the NPs. This work demonstrates that plants grown with CuO or ZnO NPs showed cross-protection from different challenges such as metal stress and drought.

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