Dataset Information

Tolerance to Drought, Low pH and Al Combined Stress in Tibetan Wild Barley Is Associated with Improvement of ATPase and Modulation of Antioxidant Defense System.

ABSTRACT: Aluminum (Al) toxicity and drought are two major constraints on plant growth in acidic soils, negatively affecting crop performance and yield. Genotypic differences in the effects of Al/low pH and polyethyleneglycol (PEG) induced drought stress, applied either individually or in combination, were studied in Tibetan wild (XZ5, drought-tolerant; XZ29, Al-tolerant) and cultivated barley (Al-tolerant Dayton; drought-tolerant Tadmor). Tibetan wild barley XZ5 and XZ29 had significantly higher H?-ATPase, Ca²⁺Mg²⁺-ATPase, and Na?K?-ATPase activities at pH 4.0+Al+PEG than Dayton and Tadmor. Moreover, XZ5 and XZ29 possessed increased levels in reduced ascorbate and glutathione under these conditions, and antioxidant enzyme activities were largely stimulated by exposure to pH 4.0+PEG, pH 4.0+Al, and pH 4.0+Al+PEG, compared to a control and to Dayton and Tadmor. The activity of methylglyoxal (MG) was negatively correlated with increased levels of glyoxalase (Gly) I and Gly II in wild barley. Microscopic imaging of each genotype revealed DNA damage and obvious ultrastructural alterations in leaf cells treated with drought or Al alone, and combined pH 4.0+Al+PEG stress; however, XZ29 and XZ5 were less affected than Dayton and Tadmor. Collectively, the authors findings indicated that the higher tolerance of the wild barley to combined pH 4.0+Al+PEG stress is associated with improved ATPase activities, increased glyoxalase activities, reduced MG, and lower reactive oxygen species levels (like O?^- and H?O?) due to increased antioxidant enzyme activities. These results offer a broad comprehension of the mechanisms implicated in barley's tolerance to the combined stress of Al/low pH and drought, and may provide novel insights into the potential utilization of genetic resources, thereby facilitating the development of barley varieties tolerant to drought and Al/low pH stress.

SUBMITTER: Ahmed IM

PROVIDER: S-EPMC6274725 | biostudies-literature | 2018 Nov

REPOSITORIES: biostudies-literature

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Publications

Tolerance to Drought, Low pH and Al Combined Stress in Tibetan Wild Barley Is Associated with Improvement of ATPase and Modulation of Antioxidant Defense System.

Ahmed Imrul Mosaddek IM Nadira Umme Aktari UA Qiu Cheng-Wei CW Cao Fangbin F Zhang Guoping G Holford Paul P Wu Feibo F

International journal of molecular sciences 20181111 11

Aluminum (Al) toxicity and drought are two major constraints on plant growth in acidic soils, negatively affecting crop performance and yield. Genotypic differences in the effects of Al/low pH and polyethyleneglycol (PEG) induced drought stress, applied either individually or in combination, were studied in Tibetan wild (XZ5, drought-tolerant; XZ29, Al-tolerant) and cultivated barley (Al-tolerant Dayton; drought-tolerant Tadmor). Tibetan wild barley XZ5 and XZ29 had significantly higher H⁺-ATPas ...[more]

PMID: 30423885

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Project description:Drought and salinity are two of the most frequently co-occurring abiotic stresses. Despite recent advances in the elucidation of the effects of these stresses individually during the vegetative stage of plants, significant gaps exist in our understanding of the combined effects of these two frequently co-occurring stresses. Here, Tibetan wild barley XZ5 (drought tolerant), XZ16 (salt tolerant), and cultivated barley cv. CM72 (salt tolerant) were subjected to drought (D), salinity (S), or a combination of both treatments (D+S). Protein synthesis is one of the primary activities of the green part of the plant. Therefore, leaf tissue is an important parameter to evaluate drought and salinity stress conditions. Sixty differentially expressed proteins were identified by mass spectrometry (MALDI-TOF/TOF) and classified into 9 biological processes based on Gene Ontology annotation. Among them, 21 proteins were found to be expressed under drought or salinity alone; however, under D+S, 7 proteins, including S-adenosylmethionine synthetase 3 (SAMS3), were exclusively upregulated in drought-tolerant XZ5 but not in CM72. HvSAMS3 carries both N-terminal and central domains compared with Arabidopsis and activates the expression of several ethylene (ET)-responsive transcription factors. HvSAMS3 is mainly expressed in the roots and stems, and HvSAMS3 is a secretory protein located in the cell membrane and cytoplasm. Barley stripe mosaic virus-based virus-induced gene silencing (BSMV-VIGS) of HvSAMS3 in XZ5 severely compromised its tolerance to D+S and significantly reduced plant growth and K+ uptake. The reduced tolerance to the combined stress was associated with the inhibition of polyamines such as spermidine and spermine, polyamine oxidase, ethylene, biotin, and antioxidant enzyme activities. Furthermore, the exogenous application of ethylene and biotin improved the tolerance to D+S in BSMV-VIGS:HvSAMS3-inoculated plants. Our findings highlight the significance of HvSAMS3 in the tolerance to D+S in XZ5.

Project description:Aluminum (Al) is the most common metal in the Earth’s crust and Al toxicity is considered to be the most harmful abiotic stress in acidic soils that today comprise more than 50% of the world’s arable lands. The first symptom of Al toxicity is the reduction of root growth, resulting in decreased water and nutrients uptake, plant growth retardation, and finally, yield reduction. Barley (Hordeum vulgare L.), which is the fourth cereal crop in regards to cultivation area and production tonnage, belongs to crops most sensitive to toxic aluminum ions in low pH soils. We present the RNA-seq transcriptome analysis of root meristems of barley seedlings grown in hydroponics at optimal pH (6.0), low pH (4.0), and low pH with Al (10 µM of bioavailable Al3+ ions). Two independent experiments were conducted: with short-term (24 h) and long-term (7 days) Al treatment. Interestingly, in the short-term experiment, more genes were differentially expressed between root meristems grown at pH=6.0 and pH=4.0, than between those grown at pH=4.0 with and without Al treatment. The upregulated genes that were overrepresented at conditions of low pH, compared to optimal pH, were associated with response to oxidative stress, cell wall organization, and iron ion binding. Among genes downregulated by low pH were mainly those related to chromatin organization. These results show that low pH itself is a severe stress for barley plants. Among genes upregulated by short Al treatment, overrepresented were those related to response to stress condition and calcium ion binding. After 7 days of hydroponics, the number of DEGs between hydroponics at pH=4.0 and 6.0 were still high but lower than in the short-term experiment, which suggests that plants partially adapted to the low pH. Interestingly, 7 day Al treatment caused massive changes in the transcriptome profile compared to the condition of low pH alone. Over 4 000 genes were upregulated and almost 2 000 genes were downregulated by long-term Al stress. These DEGs were related to e.g. stress response, cell wall development and metal ion transport. Based on our results we can assume that both, Al3+ ions and low pH are harmful to barley plants.Additionally, we phenotyped in detail the root system of barley seedlings grown in the same hydroponic conditions for 7 days at pH=6.0, pH=4.0, and pH=4.0 with Al. The results correspond to transcriptomic data and show that low pH itself is a stress facor that causes a significant reduction of root growth and the addition of aluminum further increases this reduction. It should be underlined that in the acidic arable lands, plants are exposed simultaneously to both of these stresses (low pH and Al), as Al becomes soluble at pH below 5.5. The presented transcriptome analysis may help to find potential targets for breeding barley plants more tolerant to such conditions.

Dataset Information

Tolerance to Drought, Low pH and Al Combined Stress in Tibetan Wild Barley Is Associated with Improvement of ATPase and Modulation of Antioxidant Defense System.

Publications

Tolerance to Drought, Low pH and Al Combined Stress in Tibetan Wild Barley Is Associated with Improvement of ATPase and Modulation of Antioxidant Defense System.

Similar Datasets

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