scholarly journals Exopolysaccharides Producing Bacteria for the Amelioration of Drought Stress in Wheat

2020 ◽  
Vol 12 (21) ◽  
pp. 8876
Author(s):  
Noshin Ilyas ◽  
Komal Mumtaz ◽  
Nosheen Akhtar ◽  
Humaira Yasmin ◽  
R. Z. Sayyed ◽  
...  
Keyword(s):  
Antioxidant Enzymes ◽  
Drought Stress ◽  
Drought Tolerance ◽  
Indole Acetic Acid ◽  
Stress Hormones ◽  
Carotenoid Content ◽  
Bacterial Strains ◽  
Morphological Attributes ◽  
Vigor Index

This research was designed to elucidate the role of exopolysaccharides (EPS) producing bacterial strains for the amelioration of drought stress in wheat. Bacterial strains were isolated from a farmer’s field in the arid region of Pakistan. Out of 24 isolated stains, two bacterial strains, Bacillus subtilis (Accession No. MT742976) and Azospirillum brasilense (Accession No. MT742977) were selected, based on their ability to produce EPS and withstand drought stress. Both bacterial strains produced a good amount of EPS and osmolytes and exhibited drought tolerance individually, however, a combination of these strains produced higher amounts of EPS (sugar 6976 µg/g, 731.5 µg/g protein, and 1.1 mg/g uronic acid) and osmolytes (proline 4.4 µg/mg and sugar 79 µg/mg) and significantly changed the level of stress-induced phytohormones (61%, 49% and 30% decrease in Indole Acetic Acid (IAA), Gibberellic Acid (GA), and Cytokinin (CK)) respectively under stress, but an increase of 27.3% in Abscisic acid (ABA) concentration was observed. When inoculated, the combination of these strains improved seed germination, seedling vigor index, and promptness index by 18.2%, 23.7%, and 61.5% respectively under osmotic stress (20% polyethylene glycol, PEG6000). They also promoted plant growth in a pot experiment with an increase of 42.9%, 29.8%, and 33.7% in shoot length, root length, and leaf area, respectively. Physiological attributes of plants were also improved by bacterial inoculation showing an increase of 39.8%, 61.5%, and 45% in chlorophyll a, chlorophyll b, and carotenoid content respectively, as compared to control. Inoculations of bacterial strains also increased the production of osmolytes such asproline, amino acid, sugar, and protein by 30%, 23%, 68%, and 21.7% respectively. Co-inoculation of these strains enhanced the production of antioxidant enzymes such as superoxide dismutase (SOD) by 35.1%, catalase (CAT) by 77.4%, and peroxidase (POD) by 40.7%. Findings of the present research demonstrated that EPS, osmolyte, stress hormones, and antioxidant enzyme-producing bacterial strains impart drought tolerance in wheat and improve its growth, morphological attributes, physiological parameters, osmolytes production, and increase antioxidant enzymes.

scholarly journals Spermine: Its Emerging Role in Regulating Drought Stress Responses in Plants

Cells ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 261
Author(s):  
Md. Mahadi Hasan ◽  
Milan Skalicky ◽  
Mohammad Shah Jahan ◽  
Md. Nazmul Hossain ◽  
Zunaira Anwar ◽  
...  
Keyword(s):  
Drought Stress ◽  
Drought Tolerance ◽  
Stress Responses ◽  
Abiotic Stresses ◽  
Defense Mechanisms ◽  
Antioxidant Defense ◽  
Severe Drought ◽  
New Information ◽  
Effects Of Drought

In recent years, research on spermine (Spm) has turned up a lot of new information about this essential polyamine, especially as it is able to counteract damage from abiotic stresses. Spm has been shown to protect plants from a variety of environmental insults, but whether it can prevent the adverse effects of drought has not yet been reported. Drought stress increases endogenous Spm in plants and exogenous application of Spm improves the plants’ ability to tolerate drought stress. Spm’s role in enhancing antioxidant defense mechanisms, glyoxalase systems, methylglyoxal (MG) detoxification, and creating tolerance for drought-induced oxidative stress is well documented in plants. However, the influences of enzyme activity and osmoregulation on Spm biosynthesis and metabolism are variable. Spm interacts with other molecules like nitric oxide (NO) and phytohormones such as abscisic acid, salicylic acid, brassinosteroids, and ethylene, to coordinate the reactions necessary for developing drought tolerance. This review focuses on the role of Spm in plants under severe drought stress. We have proposed models to explain how Spm interacts with existing defense mechanisms in plants to improve drought tolerance.

scholarly journals Effects of salicylic acid, zinc and glycine betaine on morpho-physiological growth and yield of maize under drought stress

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Ramadan Shemi ◽  
Rui Wang ◽  
El-Sayed M. S. Gheith ◽  
Hafiz Athar Hussain ◽  
Saddam Hussain ◽  
...  
Keyword(s):  
Salicylic Acid ◽  
Antioxidant Enzymes ◽  
Drought Stress ◽  
Gas Exchange ◽  
Drought Tolerance ◽  
Glycine Betaine ◽  
Field Capacity ◽  
Yield Attributes ◽  
Chlorophyll Contents ◽  
Water Conditions

AbstractDrought is one of the major environmental stresses that negatively affect the maize (Zea mays L.) growth and production throughout the world. Foliar applications of plant growth regulators, micronutrients or osmoprotectants for stimulating drought-tolerance in plants have been intensively reported. A controlled pot experiment was conducted to study the relative efficacy of salicylic acid (SA), zinc (Zn), and glycine betaine (GB) foliar applications on morphology, chlorophyll contents, relative water content (RWC), gas-exchange attributes, activities of antioxidant enzymes, accumulations of reactive oxygen species (ROS) and osmolytes, and yield attributes of maize plants exposed to two soil water conditions (85% field capacity: well-watered, 50% field capacity: drought stress) during critical growth stages. Drought stress significantly reduced the morphological parameters, yield and its components, RWC, chlorophyll contents, and gas-exchange parameters except for intercellular CO2 concentration, compared with well water conditions. However, the foliar applications considerably enhanced all the above parameters under drought. Drought stress significantly (p < 0.05) increased the hydrogen peroxide and superoxide anion contents, and enhanced the lipid peroxidation rate measured in terms of malonaldehyde (MDA) content. However, ROS and MDA contents were substantially decreased by foliar applications under drought stress. Antioxidant enzymes activity, proline content, and the soluble sugar were increased by foliar treatments under both well-watered and drought-stressed conditions. Overall, the application of GB was the most effective among all compounds to enhance the drought tolerance in maize through reduced levels of ROS, increased activities of antioxidant enzymes and higher accumulation of osmolytes contents.

scholarly journals Amplification of early drought responses caused by volatile cues emitted from neighboring plants

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Jieyang Jin ◽  
Mingyue Zhao ◽  
Ting Gao ◽  
Tingting Jing ◽  
Na Zhang ◽  
...  
Keyword(s):  
Drought Stress ◽  
Drought Tolerance ◽  
Plant Density ◽  
Stomatal Closure ◽  
Induced Volatiles ◽  
Positive Regulators ◽  
Tea Plants ◽  
Aba Content ◽  
Volatile Cues

AbstractPlants have developed sophisticated mechanisms to survive in dynamic environments. Plants can communicate via volatile organic compounds (VOCs) to warn neighboring plants of threats. In most cases, VOCs act as positive regulators of plant defense. However, the communication and role of volatiles in response to drought stress are poorly understood. Here, we showed that tea plants release numerous VOCs. Among them, methyl salicylate (MeSA), benzyl alcohol, and phenethyl alcohol markedly increased under drought stress. Interestingly, further experiments revealed that drought-induced MeSA lowered the abscisic acid (ABA) content in neighboring plants by reducing 9-cis-epoxycarotenoid dioxygenase (NCED) gene expression, resulting in inhibition of stomatal closure and ultimately decreasing early drought tolerance in neighboring plants. Exogenous application of ABA reduced the wilting of tea plants caused by MeSA exposure. Exposure of Nicotiana benthamiana to MeSA also led to severe wilting, indicating that the ability of drought-induced MeSA to reduce early drought tolerance in neighboring plants may be conserved in other plant species. Taken together, these results provide evidence that drought-induced volatiles can reduce early drought tolerance in neighboring plants and lay a novel theoretical foundation for optimizing plant density and spacing.

scholarly journals Transcriptome Analysis Revealed GhWOX4 Intercedes Myriad Regulatory Pathways to Modulate Drought Tolerance and Vascular Growth in Cotton

2021 ◽  
Vol 22 (2) ◽  
pp. 898
Author(s):  
Muhammad Sajjad ◽  
Xi Wei ◽  
Lisen Liu ◽  
Fuguang Li ◽  
Xiaoyang Ge
Keyword(s):  
Transcription Factors ◽  
Drought Stress ◽  
Drought Tolerance ◽  
Plant Growth ◽  
Growth And Development ◽  
Differentially Expressed ◽  
Growth And Yield ◽  
Regulatory Pathways ◽  
Vascular Growth

Cotton is a paramount cash crop around the globe. Among all abiotic stresses, drought is a leading cause of cotton growth and yield loss. However, the molecular link between drought stress and vascular growth and development is relatively uncharted. Here, we validated a crucial role of GhWOX4, a transcription factor, modulating drought stress with that of vasculature growth in cotton. Knock-down of GhWOX4 decreased the stem width and severely compromised vascular growth and drought tolerance. Conversely, ectopic expression of GhWOX4 in Arabidopsis enhanced the tolerance to drought stress. Comparative RNAseq analysis revealed auxin responsive protein (AUX/IAA), abscisic acid (ABA), and ethylene were significantly induced. Additionally, MYC-bHLH, WRKY, MYB, homeodomain, and heat-shock transcription factors (HSF) were differentially expressed in control plants as compared to GhWOX4-silenced plants. The promotor zone of GhWOX4 was found congested with plant growth, light, and stress response related cis-elements. differentially expressed genes (DEGs) related to stress, water deprivation, and desiccation response were repressed in drought treated GhWOX4-virus-induced gene silencing (VIGS) plants as compared to control. Gene ontology (GO) functions related to cell proliferation, light response, fluid transport, and flavonoid biosynthesis were over-induced in TRV: 156-0 h/TRV: 156-1 h (control) in comparison to TRV: VIGS-0 h/TRV: VIGS-1 h (GhWOX4-silenced) plants. This study improves our context for elucidating the pivotal role of GhWOX4 transcription factors (TF), which mediates drought tolerance, plays a decisive role in plant growth and development, and is likely involved in different regulatory pathways in cotton.

scholarly journals Mycorrhiza Fungus Rhizophagus intraradices Mediates Drought Tolerance in Eleusine coracana Seedlings

2018 ◽  
Author(s):  
Jaagriti Tyagi ◽  
Neeraj Shrivastava ◽  
A. K. Sharma ◽  
Ajit Varma ◽  
Ramesh Namdeo Pudake
Keyword(s):  
Drought Stress ◽  
Drought Tolerance ◽  
Finger Millet ◽  
Soluble Sugars ◽  
Leaf Tissue ◽  
Am Fungi ◽  
Mycorrhizal Symbiosis ◽  
Severe Drought ◽  
Rhizophagus Intraradices

Under abiotic stress conditions, arbuscular mycorrhizal (AM) fungi help plants by improving nutrient and water uptake. Finger millet is an arid crop having soils with poor water holding capacity. Therefore, it is difficult for the plants to obtain water and mineral nutrients from the soil to sustain life. To understand the role of mycorrhizal symbiosis in water and mineral up-take from the soil, we studied the role of Rhizophagus intraradices colonization and its beneficial role for drought stress tolerance in finger millet seedling. Under severe drought stress condition, AM inoculation led to the significant increase in plant growth (7%), phosphorus, and chlorophyll content (29%). Also, the level of osmolytes including proline and soluble sugars were found in higher quantities in AM inoculated seedlings under drought stress. Under water stress, the lipid peroxidation in leaves of mycorrhized seedlings was reduced by 29%. The flavonoid content of roots in AM colonized seedlings was found 16% higher compared to the control, whereas the leaves were accumulated more phenol. Compared to the control, ascorbate level was found to be 25% higher in leaf tissue of AM inoculated seedlings. Moreover, glutathione (GSH) level was increased in mycorrhiza inoculated seedlings with a maximum increment of 182% under severe stress. The results demonstrated that AM provided drought tolerance to the finger millet seedlings through a stronger root system, greater photosynthetic efficiency, a more efficient antioxidant system and improved osmoregulation.

Revealing the Effects of Potassium on Rice Roots under Moisture Stress

2018 ◽  
Vol 102 (4) ◽  
pp. 28-31
Author(s):  
Kirti Bardhan ◽  
Dipika Patel ◽  
Dhiraji Patel
Keyword(s):  
Drought Stress ◽  
Drought Tolerance ◽  
Root Architecture ◽  
Plant Root ◽  
Moisture Stress ◽  
Rice Roots ◽  
Aerial Parts ◽  
Organ Level ◽  
Plant Root System

The role of K in providing drought tolerance in the aerial parts of plants at the cellular, molecular, tissue, and organ level is well established compared to the plant root system. However, it is known that plants acquire soil water from deeper layers by modifying root architecture. The current study investigated the role of K in changing root architecture to facilitate more water acquisition as a mechanism to mitigate drought stress.

scholarly journals Drought-hardening improves drought tolerance in Nicotiana tabacum at physiological, biochemical, and molecular levels

2020 ◽  
Vol 20 (1) ◽  
Author(s):  
Rayyan Khan ◽  
Xinghua Ma ◽  
Shahen Shah ◽  
Xiaoying Wu ◽  
Aaqib Shaheen ◽  
...  
Keyword(s):  
Drought Stress ◽  
Drought Tolerance ◽  
Defense Mechanisms ◽  
Soluble Sugar ◽  
Negative Effects ◽  
Hardening Treatment ◽  
Tobacco Seedlings ◽  
Negative Impacts ◽  
Drought Hardening

Abstract Background Drought stress is the most harmful one among other abiotic stresses with negative impacts on crop growth and development. Drought-hardening is a feasible and widely used method in tobacco seedlings cultivation. It has gained extensive interests due to its role in improving drought tolerance. This research aimed to investigate the role of drought-hardening and to unravel the multiple mechanisms underlying tobacco drought tolerance and adaptation. Results This study was designed in which various drought-hardening treatments (CK (no drought-hardening), T1 (drought-hardening for 24 h), T2 (drought-hardening for 48 h), and T3 (drought-hardening for 72 h)) were applied to two tobacco varieties namely HongHuaDaJinYuan (H) and Yun Yan-100 (Y). The findings presented a complete framework of drought-hardening effect at physiological, biochemical, and gene expression levels of the two tobacco varieties under drought stress. The results showed that T2 and T3 significantly reduced the growth of the two varieties under drought stress. Similarly, among the various drought-hardening treatments, T3 improved both the enzymatic (POD, CAT, APX) and non-enzymatic (AsA) defense systems along with the elevated levels of proline and soluble sugar to mitigate the negative effects of oxidative damage and bringing osmoregulation in tobacco plants. Finally, the various drought-hardening treatments (T1, T2, and T3) showed differential regulation of genes expressed in the two varieties, while, particularly T3 drought-hardening treatment-induced drought tolerance via the expression of various stress-responsive genes by triggering the biosynthesis pathways of proline (P5CS1), polyamines (ADC2), ABA-dependent (SnRK2, AREB1), and independent pathways (DREB2B), and antioxidant defense-related genes (CAT, APX1, GR2) in response to drought stress. Conclusions Drought-hardening made significant contributions to drought tolerance and adaptation in two tobacco variety seedlings by reducing its growth and, on the other hand, by activating various defense mechanisms at biochemical and molecular levels. The findings of the study pointed out that drought-hardening is a fruitful strategy for conferring drought tolerance and adaptations in tobacco. It will be served as a useful method in the future to understand the drought tolerance and adaptation mechanisms of other plant species. Graphical abstract Drought-hardening improved drought tolerance and adaptation of the two tobacco varieties. T1 indicates drought-hardening for 24 h, T2 indicates drought-hardening for 48 h, T3 indicates drought-hardening for 72 h

scholarly journals Role of Exogenous-Applied Salicylic Acid, Zinc And Glycine Betaine To Improve Drought-Tolerance In Wheat During Reproductive Growth Stages

2021 ◽  
Author(s):  
Ramadan Shemi ◽  
Rui Wang ◽  
El-Sayed M.S. Gheith ◽  
Hafiz Athar Hussain ◽  
Linna Cholidah ◽  
...  
Keyword(s):  
Salicylic Acid ◽  
Antioxidant Enzymes ◽  
Drought Stress ◽  
Gas Exchange ◽  
Drought Tolerance ◽  
Glycine Betaine ◽  
Field Capacity ◽  
Growth Stages ◽  
Yield Parameters ◽  
Ros Accumulation

Abstract Background: Drought has become a dangerous threat to reduce crop productivity throughout the world. Exogenous application of regulators, micronutrients, or osmoprotectants for inducing drought-tolerance in field crops has been effectively adopted. A controlled pot study was performed to investigate the relative efficacy of salicylic acid (SA), zinc (Zn), and glycine betaine (GB) as foliar applications on the growth, tissues pigments content, relative water content (RWC), leaf gas exchange, antioxidant enzymes activity, reactive oxygen species (ROS) accumulation, osmolytes contents and the yield parameters of wheat plants subjected to two soil water conditions (85% field capacity: well-watered, 50% field capacity: water-deficient) during reproductive growth stages.Results: Water deficient conditions significantly decreased the growth, yield parameters, RWC, photosynthesis pigment, and gas exchange attributes except for intercellular CO2 concentration. However, foliar applications remarkably improved the growth parameters under water deficit conditions. Drought stress statistically increased the contents of hydrogen peroxide (H2O2), superoxide anion radical (O2 •−), and malonaldehyde (MDA), and elevated the harmful oxidation to cell lipids in plants, however, they were considerably reduced by foliar applications. Activities of all antioxidant enzymes, proline content, and soluble sugar were increased in response to foliar applications under water deficit conditions.Conclusions: Overall, foliar application of GB, SA, and Zn compounds improved the drought-tolerance in wheat by decreasing the ROS accumulation, promoting enzymatic antioxidants, and increasing osmolytes accumulation. Finally, GB treatment was most effective in thoroughly assessed parameters of wheat followed by SA and Zn applications to alleviate the adverse effects of drought stress.

scholarly journals Characterisation of multi-metal resistant Serratia sp. GP01 for treatment of effluent from fertilizer industries

2021 ◽  
Author(s):  
Hrudananda Sahoo ◽  
Sushama Kumari ◽  
Darpa Saurav Jyethi ◽  
Umesh Chandra Naik
Keyword(s):  
Heavy Metals ◽  
Antioxidant Enzymes ◽  
Health Hazard ◽  
Metal Resistance ◽  
Bacterial Strains ◽  
16S Rdna Sequence ◽  
Reductase Gene ◽  
Enzymatic Reduction ◽  
Mapping Analysis

Abstract The effluent generated from fertilizer plants in Paradeep in the coast of the Bay of Bengal is the major pollutant causing health hazard in the vicinity of the area with respect to plants, animals and microbes. Samples of effluent were found to contain heavy metals (mg L-1): Cr (100), Ni (36.975), Mn (68.673), Pb (20.133), Cu (74.44), Zn (176.716), Hg (5.358) and As (24.287) as analyzed by XRF. Indigenous bacterial strains were screened for chromate and multi-metal resistance to remediate the toxic pollutants. The isolated strain G1 was identified as Serratia sp. through 16S-rDNA sequence homology. Potent strain Serratia sp. GP01 treated with 100 mg L-1 of K2Cr2O7 has shown the efficacy of reducing 69.05 mg L-1 of Cr over 48 h of incubation. Further, presence of chromate reductase gene (ChR) in Serratia sp. confirmed the enzymatic reduction of Cr (VI). SEM-EDX and SEM mapping analysis revealed substantial biosorption of Cr and other heavy metals present in effluent by Serratia sp. GP01. Antioxidant enzymes such as catalase (72.15 U mL-1), SOD (57.14 U mL-1) and peroxidase (62.49 U mL-1) were found to be higher as compared to the control condition. FTIR study also revealed the role of N-H, O-H, C = C, C-H, C-O, C-N, and C = O functional groups of the cell surface of Serratia sp. treated with K2Cr2O7 and effluent from the fertilizer industry. Isolated strain Serratia sp. could be used for the detoxification of Cr (VI) and other heavy metals in fertilizer plant effluent.

scholarly journals Reciprocal grafting between clones with contrasting drought tolerance suggests a key role of abscisic acid in coffee acclimation to drought stress

2018 ◽  
Vol 85 (2) ◽  
pp. 221-229 ◽  
Author(s):  
Vânia Aparecida Silva ◽  
Fernanda Manso Prado ◽  
Werner Camargos Antunes ◽  
Rita Márcia Cardoso Paiva ◽  
Maria Amélia Gava Ferrão ◽  
...  
Keyword(s):  
Abscisic Acid ◽  
Drought Stress ◽  
Drought Tolerance
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