Melatonin alleviates aluminium toxicity through modulating antioxidative enzymes and enhancing organic acid anion exudation in soybean

2017 ◽  
Vol 44 (10) ◽  
pp. 961 ◽  
Author(s):  
Jiarong Zhang ◽  
Bingjie Zeng ◽  
Yawen Mao ◽  
Xiangying Kong ◽  
Xinxun Wang ◽  
...  
Keyword(s):  
Plant Growth ◽  
Root Growth ◽  
Critical Role ◽  
Aluminium Toxicity ◽  
Al Toxicity ◽  
Root Growth Inhibition ◽  
H2o2 Production ◽  
Plant Responses ◽  
Al Stress ◽  
High Concentrations

Aluminium (Al) toxicity is a major chemical constraint limiting plant growth and production on acidic soils. Melatonin (N-acetyl-5-methoxytryptamine) is a ubiquitous molecule that plays crucial roles in plant growth and stress tolerance. However, there is no knowledge regarding whether melatonin is involved in plant responses to Al stress. Here, we show that optimal concentrations of melatonin could effectively ameliorate Al-induced phytotoxicity in soybean (Glycine max L.). The concentration of melatonin in roots was significantly increased by the 50 μM Al treatment. Such an increase in endogenous melatonin coincided with the upregulation of the gene encoding acetyltransferase NSI-like (nuclear shuttle protein-interacting) in soybean roots. Supplementation with low concentrations of melatonin (0.1 and 1 μM) conferred Al resistance as evident in partial alleviation of root growth inhibition and decreased H2O2 production: in contrast, high concentrations of melatonin (100 and 200 μM) had an opposite effect and even decreased root growth in Al-exposed seedlings. Mitigation of Al stress by the 1 μM melatonin root treatment was associated with enhanced activities of the antioxidant enzymes and increased exudation of malate and citrate. In conclusion, melatonin might play a critical role in soybean resistance to Al toxicity.

scholarly journals Effects of green seaweed extract on Arabidopsis early development suggest roles for hormone signalling in plant responses to algal fertilisers

2018 ◽  
Author(s):  
Fatemeh Ghaderiardakani ◽  
Ellen Collas ◽  
Deborah Kohn Damiano ◽  
Katherine Tagg ◽  
Neil S. Graham ◽  
...  
Keyword(s):  
Plant Growth ◽  
Root Growth ◽  
Growth Inhibition ◽  
Early Development ◽  
Land Plant ◽  
Root Growth Inhibition ◽  
Plant Responses ◽  
Germination Inhibition ◽  
Green Seaweed ◽  
Algal Extracts

AbstractThe growing population requires sustainable, environmentally-friendly crops. The plant growth-enhancing properties of algal extracts have suggested their use as biofertilisers. The mechanism(s) by which algal extracts affect plant growth are unknown.We examined the effects of extracts from the common green seaweed Ulva intestinalis on germination and root development in the model land plant Arabidopsis thaliana. Ulva extract concentrations above 0.1% inhibited Arabidopsis germination and root growth. Ulva extract <0.1% stimulated root growth. All concentrations of Ulva extract inhibited lateral root formation. An abscisic-acid-insensitive mutant, abi1, showed altered sensitivity to germination- and root growth-inhibition inhibition. Ethylene- and cytokinin-insensitive mutants were partly insensitive to germination-inhibition. This suggests that different mechanisms mediate each effect of Ulva extract on early Arabidopsis development and that multiple hormones contribute to germination-inhibition.Elemental analysis showed that Ulva contains high levels of Aluminium ions (Al3+). Ethylene and cytokinin have been suggested to function in Al3+-mediated root growth inhibition: our data suggest that if Ulva Al3+ levels inhibit root growth, this is via a novel mechanism. We suggest algal extracts should be used cautiously as fertilisers, as the inhibitory effects on early development may outweigh any benefits if the concentration of extract is too high.

scholarly journals Aluminium Toxicity Targets in Plants

2012 ◽  
Vol 2012 ◽  
pp. 1-8 ◽  
Author(s):  
Sónia Silva
Keyword(s):  
Root Growth ◽  
Growth Inhibition ◽  
Aluminium Toxicity ◽  
Al Toxicity ◽  
Plant Production ◽  
Root Growth Inhibition ◽  
Ros Production ◽  
The Third ◽  
Metallic Element ◽  
Root Cell Wall

Aluminium (Al) is the third most abundant metallic element in soil but becomes available to plants only when the soil pH drops below 5.5. At those conditions, plants present several signals of Al toxicity. As reported by literature, major consequences of Al exposure are the decrease of plant production and the inhibition of root growth. The root growth inhibition may be directly/indirectly responsible for the loss of plant production. In this paper the most remarkable symptoms of Al toxicity in plants and the latest findings in this area are addressed. Root growth inhibition, ROS production, alterations on root cell wall and plasma membrane, nutrient unbalances, callose accumulation, and disturbance of cytoplasmic Ca2+ homeostasis, among other signals of Al toxicity are discussed, and, when possible, the behavior of Al-tolerant versus Al-sensitive genotypes under Al is compared.

scholarly journals THE EFFECTS OF LIGHT QUALITY ON ENDOGENOUS CYTOKININ LEVELS IN IPT-TRANSGENIC TOBACCO

HortScience ◽  
1996 ◽  
Vol 31 (5) ◽  
pp. 756f-757
Author(s):  
Sandra B. Wilson ◽  
Dennis R. Decoteau
Keyword(s):  
Plant Growth ◽  
Growth And Development ◽  
Nicotiana Plumbaginifolia ◽  
Zeatin Riboside ◽  
Cauliflower Mosaic Virus ◽  
Plant Responses ◽  
Plant Growth And Development ◽  
High Concentrations ◽  
Whole Plants ◽  
Virus Promoter

Similarities exist between the effects of phytochrome and cytokinins on plant growth and development (e.g., chloroplast development, amaranthin synthesis, seed germination). It is unclear, however, if and how these two systems interact. The coaction between phytochrome and cytokinins was investigated by using Nicotiana plumbaginifolia plants transformed with the isopentenyl transferase (ipt) cytokinin gene and treated with end-of-day (EOD) red (R) and far-red (FR) light. The ipt gene was under control of either a constitutive cauliflower mosaic virus promoter (35S-plants) or an inducible, heat shock promoter (HS-plants). When treated with EOD FR light, whole plants were characterized by decreased chlorophyll concentrations and increased fresh weights. When treated with EOD R light, 35S-plants contained high concentrations of zeatin riboside (ZR) compared to plants treated with EOD FR light. When treated with EOD FR light, HS-plants contained high concentrations of ZR compared to plants treated with EOD R light. Both cytokinin responses were photoreversible. The reasons for the differences between the 35S- and HS-plant responses are not known. Results appear to implicate interactions between phytochrome and cytokinins in plant growth and development.

scholarly journals Crosstalk between Brassinosteroid and Redox Signaling Contributes to the Activation of CBF Expression during Cold Responses in Tomato

Antioxidants ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 509
Author(s):  
Pingping Fang ◽  
Yu Wang ◽  
Mengqi Wang ◽  
Feng Wang ◽  
Cheng Chi ◽  
...  
Keyword(s):  
Reactive Oxygen Species ◽  
Cold Stress ◽  
Stress Responses ◽  
Critical Role ◽  
Reactive Oxygen ◽  
Central Component ◽  
H2o2 Production ◽  
Plant Responses ◽  
Oxygen Species ◽  
Loss Of Function

Brassinosteroids (BRs) play a critical role in plant responses to stress. However, the interplay of BRs and reactive oxygen species signaling in cold stress responses remains unclear. Here, we demonstrate that a partial loss of function in the BR biosynthesis gene DWARF resulted in lower whilst overexpression of DWARF led to increased levels of C-REPEAT BINDING FACTOR (CBF) transcripts. Exposure to cold stress increased BR synthesis and led to an accumulation of brassinazole-resistant 1 (BZR1), a central component of BR signaling. Mutation of BZR1 compromised the cold- and BR-dependent increases in CBFs and RESPIRATORY BURST OXIDASE HOMOLOG 1(RBOH1) transcripts, as well as preventing hydrogen peroxide (H2O2) accumulation in the apoplast. Cold- and BR-induced BZR1 bound to the promoters of CBF1, CBF3 and RBOH1 and promoted their expression. Significantly, suppression of RBOH1 expression compromised cold- and BR-induced accumulation of BZR1 and related increases in CBF transcripts. Moreover, RBOH1-dependent H2O2 production regulated BZR1 accumulation and the levels of CBF transcripts by influencing glutathione homeostasis. Taken together, these results demonstrate that crosstalk between BZR1 and reactive oxygen species mediates cold- and BR-activated CBF expression, leading to cold tolerance in tomato (Solanum lycopersicum).

scholarly journals Identification of beneficial and detrimental bacteria that impact sorghum responses to drought using multi-scale and multi-system microbiome comparisons

2021 ◽  
Author(s):  
Mingsheng Qi ◽  
Jeffrey C. Berry ◽  
Kira Veley ◽  
Lily O’Connor ◽  
Omri M. Finkel ◽  
...  
Keyword(s):  
Drought Stress ◽  
Plant Growth ◽  
Root Growth ◽  
High Throughput ◽  
Field Experiments ◽  
Crop Yields ◽  
Model Systems ◽  
Root Growth Inhibition ◽  
Leaf Water Content ◽  
Bacterial Strains

AbstractBackgroundDrought is a major abiotic stress that limits agricultural productivity. Previous field-level experiments have demonstrated that drought decreases microbiome diversity in the root and rhizosphere and may lead to enrichment of specific groups of microbes, such as Actinobacteria. How these changes ultimately affect plant health is not well understood. In parallel, model systems have been used to tease apart the specific interactions between plants and single, or small groups of microbes. However, translating this work into crop species and achieving increased crop yields within noisy field settings remains a challenge. Thus, the next scientific leap forward in microbiome research must cross the great lab-to-field divide. Toward this end, we combined reductionist, transitional and ecological approaches, applied to the staple cereal crop sorghum to identify key beneficial and detrimental, root associated microbes that robustly affect drought stressed plant phenotypes.ResultsFifty-three bacterial strains, originally characterized for association with Arabidopsis, were applied to sorghum seeds and their effect on root growth was monitored for seven days. Two Arthrobacter strains, members of the Actinobacteria phylum, caused root growth inhibition (RGI) in Arabidopsis and sorghum. In the context of synthetic communities, strains of Variovorax were able to protect both Arabidopsis and sorghum from the RGI caused by Arthrobacter. As a transitional system, we tested the synthetic communities through a 24-day high-throughput sorghum phenotyping assay and found that during drought stress, plants colonized by Arthrobacter were significantly smaller and had reduced leaf water content as compared to control plants. However, plants colonized by both Arthrobacter and Variovorax performed as well or better than control plants. In parallel, we performed a field trial wherein sorghum was evaluated across well-watered and drought conditions. Drought responsive microbes were identified, including an enrichment in Actinobacteria, consistent with previous findings. By incorporating data on soil properties into the microbiome analysis, we accounted for experimental noise with a newly developed method and were then able to observe that the abundance of Arthrobacter strains negatively correlated with plant growth. Having validated this approach, we cross-referenced datasets from the high-throughput phenotyping and field experiments and report a list of high confidence bacterial taxa that positively associated with plant growth under drought stress.ConclusionsA three-tiered experimental system connected reductionist and ecological approaches and identified beneficial and deleterious bacterial strains for sorghum under drought stress.

Auxin-modulated root growth inhibition in Arabidopsis thaliana seedlings with ammonium as the sole nitrogen source

2015 ◽  
Vol 42 (3) ◽  
pp. 239 ◽  
Author(s):  
Huaiyu Yang ◽  
Jenny von der Fecht-Bartenbach ◽  
Jiřř Friml ◽  
Jan U. Lohmann ◽  
Benjamin Neuhäuser ◽  
...  
Keyword(s):  
Arabidopsis Thaliana ◽  
Root Growth ◽  
Nitrogen Source ◽  
Seedling Survival ◽  
Root Growth Inhibition ◽  
Gus Reporter ◽  
Primary Roots ◽  
Hormone Responses ◽  
Ammonium Stress ◽  
High Concentrations

Ammonium is the major nitrogen source in some plant ecosystems but is toxic at high concentrations, especially when available as the exclusive nitrogen source. Ammonium stress rapidly leads to various metabolic and hormonal imbalances that ultimately inhibit root and shoot growth in many plant species, including Arabidopsis thaliana (L.) Heynh. To identify molecular and genetic factors involved in seedling survival with prolonged exclusive NH4+ nutrition, a transcriptomic analysis with microarrays was used. Substantial transcriptional differences were most pronounced in (NH4)2SO4-grown seedlings, compared with plants grown on KNO3 or NH4NO3. Consistent with previous physiological analyses, major differences in the expression modules of photosynthesis-related genes, an altered mitochondrial metabolism, differential expression of the primary NH4+ assimilation, alteration of transporter gene expression and crucial changes in cell wall biosynthesis were found. A major difference in plant hormone responses, particularly of auxin but not cytokinin, was striking. The activity of the DR5::GUS reporter revealed a dramatically decreased auxin response in (NH4)2SO4-grown primary roots. The impaired root growth on (NH4)2SO4 was partially rescued by exogenous auxin or in specific mutants in the auxin pathway. The data suggest that NH4+-induced nutritional and metabolic imbalances can be partially overcome by elevated auxin levels.

scholarly journals Soil aluminium toxicity in New Zealand pastoral farming – a review

2018 ◽  
pp. 129-136
Author(s):  
Jeff D Morton ◽  
Jim L Moir
Keyword(s):  
New Zealand ◽  
Soil Ph ◽  
White Clover ◽  
Soil Depth ◽  
Plant Root ◽  
Aluminium Toxicity ◽  
Field Trials ◽  
Al Toxicity ◽  
High Concentrations ◽  
Extractable Soil

As most New Zealand pastoral soils are acidic, aluminium (Al) can be present at high concentrations and restrict plant root growth and shoot yield. In field trials, Al toxicity in white clover has been associated with CaCl2-extractable soil Al levels of 3-5 ppm or exchangeable soil KCl-extractable levels of 1-2 me/100g, when soil pH levels were below 5.5-5.7 in the top 75 mm. Lucerne is less tolerant of Al toxicity than white clover and ryegrass, which in turn are less tolerant than Lotus spp., arrow leaf, subterranean, Caucasian, Persian and gland clovers, and naturalised adventive annuals such as cluster, haresfoot, striated and suckling clovers. Soil Al toxicity generally increases with soil depth. Soil pH is a reliable indicator of soil Al and, on average, can be increased by 0.1 units/tonne/ha of applied lime to reduce soil Al to below the toxic range. Lime application is the most effective strategy where it can be ground-applied. A key limitation of ground-applied lime to reduce Al toxicity is that its movement down the soil only occurs slowly except in high rainfall areas. Soil Al and pH levels and legume content in hill soils varies according to slope and aspect and there is an opportunity to differentially apply lime by air to areas with low soil pH and more legume, for the best economic return.

Aluminum toxicity could be mitigated with boron by altering the metabolic patterns of amino acids and carbohydrates rather than organic acids in trifoliate orange

2019 ◽  
Vol 39 (9) ◽  
pp. 1572-1582 ◽  
Author(s):  
Lei Yan ◽  
Muhammad Riaz ◽  
Yalin Liu ◽  
Yu Zeng ◽  
Cuncang Jiang
Keyword(s):  
Amino Acids ◽  
Citric Acid ◽  
Root Growth ◽  
Organic Acids ◽  
Aluminum Toxicity ◽  
Al Toxicity ◽  
Trifoliate Orange ◽  
Al Stress ◽  
Threonic Acid ◽  
Induced Changes

Abstract Aluminum (Al) toxicity is the main constraint of root growth and productivity on arable acidic soil. Although boron (B) is used to ameliorate Al stress, the exact mechanisms underlying the effects of B on Al-induced alteration on root metabolites are poorly understood, especially in the trifoliate orange, which is an important rootstock in China. Therefore, a hydroponics experiment was conducted to explore the mechanisms of B mitigates Al toxicity in roots of citrus by metabolomics. A total of 60 metabolites were identified and analyzed in the present study. The 17 amino acids and 8 sugars were up-regulated in Al-treated roots, mainly histidine, cycloleucine, asparagine, citrulline, raffinose and trehalose, and increased by 38.5-, 8.7-, 6.0-, 6.0-, 7.5- and 6.6-fold, respectively. Meanwhile, significant down-regulation of aspartic acid, isoleucine, glutamic acid and six sugars were indicated under Al stress. Aluminum induced a decrease of nine organic acids, especially l-malic acid, citric acid and threonic acid, by 98.2, 93.6 and 95.1%, respectively. Interestingly, in the presence of Al, B application decreased the contents of asparagine, cycloleucine, citrulline and histidine as well as myo-inositol, raffinose, galactinol and 3,6-anhydro-d-galactose by 52.2, 57.4, 46.7, 63.0, 65.4, 74.3, 62.5 and 55.0%, respectively. However, there was no obvious difference in the organic acid contents in Al-stressed roots treated with B. Conclusively, our results show that B regulates the metabolic patterns of amino acids and carbohydrates and reduces Al toxicity. Nevertheless, B addition did not affect the Al-induced changes in the metabolic modes of organic acids.

scholarly journals SALINITY STRESS RESPONSES OF MINIATURE DWARF TOMATO IN A WHOLE PLANT MICROCULTURE EVALUATION SYSTEM

HortScience ◽  
1990 ◽  
Vol 25 (9) ◽  
pp. 1149c-1149
Author(s):  
M. A. L. Smith ◽  
S. L. Knight ◽  
M. J. Bass
Keyword(s):  
Root Growth ◽  
Stress Responses ◽  
Evaluation System ◽  
Time Course ◽  
Shoot Growth ◽  
Root Growth Inhibition ◽  
Plant Responses ◽  
Tissue Quality ◽  
Osmotic Concentration ◽  
Whole Plant

A whole plant microculture (WPMC) screening system facilitated rapid, quantitative appraisal of salt stress effects on `Micro-Tom' miniature dwarf tomato. Axillary bud explants were micropropagated on a hormone-free control medium (conductivity = 3.3 dS m-1), gradually introduced to treatments with increasing NaCl or Na2SO4 concentrations via biweekly subculture to fresh media (7,6, 12.8, or 18 dS m-1), and monitored over a subsequent 5 week culture period. Non-intrusive video image analysis techniques were adapted to quantify morphometric (shoot growth rate, area, and length; root length and area) and photometric (ruler and tissue quality) plant responses. Shoot growth was only slightly inhibited at 7.6 and 12.8 dS m-1, but was severely stunted and distorted on high salt (18 dS m-1) media. Root growth inhibition (significantly shorter and thinner primary rants) was first evident at 12.8 dS m-1 after 3 weeks of treatment. At 18 dS m-1, conspicuous retardation of root growth relative to controls could be gauged after only one week. Shoot tip chlorosis was observed in the lowest salt-supplemented treatment after three to four weeks of culture, but overall shoot yellowing at the two highest conductivities was marked after only a few days. Chlorosis symptoms were not uniform within treatments. Cell osmotic concentration showed a linear increase with increasing medium salinity. The WPMC system expedited time course observations of stress symptom development, paralleled stress response trends observed in solution culture tests, and provided an excellent vehicle to investigate plant adaptation to saline conditions.

scholarly journals Short-term Aluminum Stress Differentially Affects the Photochemical Efficiency of Photosystem II in Highbush Blueberry Genotypes

2009 ◽  
Vol 134 (1) ◽  
pp. 14-21 ◽  
Author(s):  
Marjorie Reyes-Diaz ◽  
Miren Alberdi ◽  
Maria de la Luz Mora
Keyword(s):  
Photosystem Ii ◽  
Root Growth ◽  
Photochemical Efficiency ◽  
Photosynthetic Apparatus ◽  
Acid Soils ◽  
Vaccinium Corymbosum ◽  
Al Toxicity ◽  
Highbush Blueberry ◽  
Total Recovery ◽  
Al Stress

Aluminum (Al) toxicity is a major agronomic problem in acid soils. Most studies regarding Al stress focus on phenomena occurring in the roots; however, less is known about the effects of Al stress on photosynthetic apparatus functionality. Our aim was to rank three highbush blueberry (Vaccinium corymbosum) cultivars according to their tolerance to acid and Al stresses. Additionally, the levels of Al toxicity for highbush blueberry were established. ‘Brigitta’, ‘Legacy’, and ‘Bluegold’ were grown in a greenhouse in hydroponic solutions containing different Al concentrations (0, 25, 50, 75, and 100 μm) for 0 to 48 h and were allowed to recover (without Al) over 24 h. In all Al-treated cultivars, root growth inhibition was found at the highest Al treatment. However, ‘Brigitta’ also showed root growth up to 75 μm Al. Photochemical parameters decreased substantially due to Al treatments in ‘Bluegold’ (up to 98% inhibition) and ‘Legacy’ (up to 80% inhibition) without total recovery. In contrast, ‘Brigitta’ showed a better photosystem II performance and root growth than the other cultivars. These results suggest that ‘Brigitta’ is the best cultivar for use in acid soils with Al toxicity, followed by ‘Legacy’. ‘Bluegold’ was highly sensitive to Al stress. In addition, Al toxicity levels for blueberries depend on the genotype studied.

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