Mycorrhiza Fungus Rhizophagus intraradices Mediates Drought Tolerance in Eleusine coracana Seedlings

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.

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Effect of Rhizophagus intraradices on growth and physiological performance of Finger Millet (Eleusine coracana L.) under drought stress

Plant Science Today ◽

10.14719/pst.2021.8.4.1240 ◽

2021 ◽

Vol 8 (4) ◽

Author(s):

Jaagriti Tyagi ◽

Neeraj Shrivastava ◽

AK Sharma ◽

Ajit Varma ◽

Ramesh Pudake

Keyword(s):

Drought Stress ◽

Finger Millet ◽

Soluble Sugars ◽

Leaf Tissue ◽

Am Fungi ◽

Eleusine Coracana ◽

Mycorrhizal Symbiosis ◽

Severe Drought ◽

Rhizophagus Intraradices

Under abiotic stress conditions, arbuscular mycorrhizal (AM) fungi help plants by improving nutrient and water uptake. Finger millet (Eleusine coracana L.) 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 such 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 seedlings. Under severe drought stress condition, AM inoculation led to the significant increase in plant growth (7 %), phosphorus and chlorophyll content (29 %). Also, under drought stress the level of osmolytes such as proline and soluble sugars were found to be increased in AM inoculated seedlings. 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 also 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.

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

Cells ◽

10.3390/cells10020261 ◽

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.

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Drought Tolerance Responses in Vegetable-Type Soybean Involve a Network of Biochemical Mechanisms at Flowering and Pod-Filling Stages

Plants ◽

10.3390/plants10081502 ◽

2021 ◽

Vol 10 (8) ◽

pp. 1502

Author(s):

Makoena Joyce Moloi ◽

Rouxlene van der Merwe

Keyword(s):

Drought Stress ◽

Drought Tolerance ◽

Soluble Sugars ◽

Seed Mass ◽

H2o2 Production ◽

Guaiacol Peroxidase ◽

Severe Drought ◽

Flowering Stage ◽

Tolerance Response ◽

Total Seed

Severe drought stress affects the production of vegetable-type soybean (Glycine max L. Merrill), which is in infancy for Africa despite its huge nutritional benefits. This study was conducted under controlled environmental conditions to establish the effects of severe drought stress on ascorbate peroxidase (APX), guaiacol peroxidase (GPX), and glutathione reductase (GR) activities as well as proline, total soluble sugars (TSS), and hydrogen peroxide (H2O2) contents of five vegetable-type soybean cultivars (UVE8, UVE14, UVE17, AGS354, AGS429) at flowering and pod-filling stages. Drought induced significant increases in the contents of proline (selectively at pod filling for AGS429), TSS (at both stages for AGS429, and only at pod filling for UVE14), and malondialdehyde (AGS354 at flowering; UVE17 at pod filling). UVE8 and AGS354 had the highest H2O2 levels at flowering under drought stress, while AGS429 had the lowest. However, AGS429 was the only cultivar with significantly increased H2O2 under drought stress. Furthermore, drought stress induced significant increases in APX, GPX, and GR activities at flowering for AGS429. AGS354 recorded the highest decline for all antioxidative enzymes, while UVE17 decreased for GPX only. All biochemical parameters, except H2O2, were significantly higher at pod filling than at the flowering stage. The relationship between H2O2 and total seed mass (TSMP) or total seed per plant (TSP) was significantly positive for both stages, while that of TSS (at flowering) and proline (at pod filling) were significantly related to total pods per plant (TPP). The study suggests that during drought, the tolerance responses of vegetable-type soybean, APX, GPX, and GR (especially at the flowering stage), function in concert to minimize H2O2 production and lipid peroxidation, thereby allowing H2O2 to function in the signaling events leading to the induction of drought tolerance. The induction of TSS at flowering and proline at pod filling is important in the drought tolerance response of this crop.

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Proteome Analysis of Date Palm (Phoenix dactylifera L.) under Severe Drought and Salt Stress

International Journal of Genomics ◽

10.1155/2016/7840759 ◽

2016 ◽

Vol 2016 ◽

pp. 1-8 ◽

Cited By ~ 6

Author(s):

Haddad A. El Rabey ◽

Abdulrahman L. Al-Malki ◽

Khalid O. Abulnaja

Keyword(s):

Salt Stress ◽

Drought Stress ◽

Drought Tolerance ◽

Date Palm ◽

Proteome Analysis ◽

Rubisco Activase ◽

2D Electrophoresis ◽

Severe Drought ◽

Protein Abundance ◽

Low Protein

Date palm cultivars differently tolerate salinity and drought stress. This study was carried out to study the response of date palm to severe salinity and drought based on leaf proteome analysis. Eighteen-month-old date palm plants were subjected to severe salt (48 g/L NaCl) and drought (82.5 g/L PEG or no irrigation) conditions for one month. Using a protein 2D electrophoresis method, 55 protein spots were analyzed using mass spectrometry. ATP synthase CF1 alpha chains were significantly upregulated under all three stress conditions. Changes in the abundance of RubisCO activase and one of the RubisCO fragments were significant in the same spots only for salt stress and drought stress with no irrigation, and oxygen-evolving enhancer protein 2 was changed in different spots. Transketolase was significantly changed only in drought stress with PEG. The expression of salt and drought stress genes of the chosen protein spots was either overexpressed or downexpressed as revealed by the high or low protein abundance, respectively. In addition, all drought tolerance genes due to no irrigation were downregulated. In conclusion, the proteome analysis of date palm under salinity and drought conditions indicated that both salinity and drought tolerance genes were differentially expressed resulting in high or low protein abundance of the chosen protein spots as a result of exposure to drought and salinity stress condition.

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A Novel WRKY Transcription Factor from Ipomoea trifida, ItfWRKY70, Confers Drought Tolerance in Sweet Potato

International Journal of Molecular Sciences ◽

10.3390/ijms23020686 ◽

2022 ◽

Vol 23 (2) ◽

pp. 686

Author(s):

Sifan Sun ◽

Xu Li ◽

Shaopei Gao ◽

Nan Nie ◽

Huan Zhang ◽

...

Keyword(s):

Drought Stress ◽

Transgenic Plants ◽

Drought Tolerance ◽

Sweet Potato ◽

Stress Responses ◽

Leaf Tissue ◽

Stomatal Aperture ◽

Ros Scavenging ◽

Ipomoea Trifida ◽

Positive Role

WRKY transcription factors are one of the important families in plants, and have important roles in plant growth, abiotic stress responses, and defense regulation. In this study, we isolated a WRKY gene, ItfWRKY70, from the wild relative of sweet potato Ipomoea trifida (H.B.K.) G. Don. This gene was highly expressed in leaf tissue and strongly induced by 20% PEG6000 and 100 μM abscisic acid (ABA). Subcellar localization analyses indicated that ItfWRKY70 was localized in the nucleus. Overexpression of ItfWRKY70 significantly increased drought tolerance in transgenic sweet potato plants. The content of ABA and proline, and the activity of SOD and POD were significantly increased, whereas the content of malondialdehyde (MDA) and H2O2 were decreased in transgenic plants under drought stress. Overexpression of ItfWRKY70 up-regulated the genes involved in ABA biosynthesis, stress-response, ROS-scavenging system, and stomatal aperture in transgenic plants under drought stress. Taken together, these results demonstrated that ItfWRKY70 plays a positive role in drought tolerance by accumulating the content of ABA, regulating stomatal aperture and activating the ROS scavenging system in sweet potato.

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Enhancement of drought tolerance in diverse Vicia faba cultivars by inoculation with plant growth-promoting rhizobacteria under newly reclaimed soil conditions

Scientific Reports ◽

10.1038/s41598-021-02847-2 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Elsayed Mansour ◽

Hany A. M. Mahgoub ◽

Samir A. Mahgoub ◽

El-Sayed E. A. El-Sobky ◽

Mohamed I. Abdul-Hamid ◽

...

Keyword(s):

Drought Stress ◽

Drought Tolerance ◽

Plant Growth ◽

Plant Growth Promoting Rhizobacteria ◽

Severe Drought ◽

Drought Conditions ◽

Moderate Drought ◽

Plant Growth Promoting ◽

Growth Promoting ◽

Effects Of Drought

AbstractWater deficit has devastating impacts on legume production, particularly with the current abrupt climate changes in arid environments. The application of plant growth-promoting rhizobacteria (PGPR) is an effective approach for producing natural nitrogen and attenuating the detrimental effects of drought stress. This study investigated the influence of inoculation with the PGPR Rhizobium leguminosarum biovar viciae (USDA 2435) and Pseudomonas putida (RA MTCC5279) solely or in combination on the physio-biochemical and agronomic traits of five diverse Vicia faba cultivars under well-watered (100% crop evapotranspiration [ETc]), moderate drought (75% ETc), and severe drought (50% ETc) conditions in newly reclaimed poor-fertility sandy soil. Drought stress substantially reduced the expression of photosynthetic pigments and water relation parameters. In contrast, antioxidant enzyme activities and osmoprotectants were considerably increased in plants under drought stress compared with those in well-watered plants. These adverse effects of drought stress reduced crop water productivity (CWP) and seed yield‐related traits. However, the application of PGPR, particularly a consortium of both strains, improved these parameters and increased seed yield and CWP. The evaluated cultivars displayed varied tolerance to drought stress: Giza-843 and Giza-716 had the highest tolerance under well-watered and moderate drought conditions, whereas Giza-843 and Sakha-4 were more tolerant under severe drought conditions. Thus, co-inoculation of drought-tolerant cultivars with R. leguminosarum and P. putida enhanced their tolerance and increased their yield and CWP under water-deficit stress conditions. This study showed for the first time that the combined use of R. leguminosarum and P. putida is a promising and ecofriendly strategy for increasing drought tolerance in legume crops.

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Overexpression of a Voltage-Dependent Anion-Selective Channel (VDAC) Protein-Encoding Gene, MsVDAC, from Medicago sativa Confers Cold and Drought Tolerance to Transgenic Tobacco

Genes ◽

10.3390/genes12111706 ◽

2021 ◽

Vol 12 (11) ◽

pp. 1706

Author(s):

Mei Yang ◽

Xinhang Duan ◽

Zhaoyu Wang ◽

Hang Yin ◽

Junrui Zang ◽

...

Keyword(s):

Drought Stress ◽

Drought Tolerance ◽

Cold Stress ◽

Medicago Sativa ◽

Transgenic Tobacco ◽

Soluble Sugars ◽

Ros Scavenging ◽

Osmotic Homeostasis ◽

Voltage Dependent ◽

Stress Responsive Genes

Voltage-dependent anion channels (VDACs) are highly conserved proteins that are involved in the translocation of tRNA and play a key role in modulating plant senescence and multiple pathways. However, the functions of VDACs in plants are still poorly understood. Here, a novel VDAC gene was isolated and identified from alfalfa (Medicago sativa L.). MsVDAC localized to the mitochondria, and its expression was highest in alfalfa roots and was induced in response to cold, drought and salt treatment. Overexpression of MsVDAC in tobacco significantly increased MDA, GSH, soluble sugars, soluble protein and proline contents under cold and drought stress. However, the activities of SOD and POD decreased in transgenic tobacco under cold stress, while the O2− content increased. Stress-responsive genes including LTP1, ERD10B and Hxk3 were upregulated in the transgenic plants under cold and drought stress. However, GAPC, CBL1, BI-1, Cu/ZnSOD and MnSOD were upregulated only in the transgenic tobacco plants under cold stress, and GAPC, CBL1, and BI-1 were downregulated under drought stress. These results suggest that MsVDAC provides cold tolerance by regulating ROS scavenging, osmotic homeostasis and stress-responsive gene expression in plants, but the improved drought tolerance via MsVDAC may be mainly due to osmotic homeostasis and stress-responsive genes.

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DEHYDRIN PROFILES OF SOME IRANIAN MELON VARIETIES (Cucumis melo L. Merr) UNDER DROUGHT STRE SS CONDITIONS

Acta Scientiarum Polonorum Hortorum Cultus ◽

10.24326/asphc.2019.6.8 ◽

2019 ◽

Vol 18 (6) ◽

pp. 75-84

Author(s):

Alireza Motallebi-Azar ◽

István Papp ◽

Anita Szegő

Keyword(s):

Drought Stress ◽

Drought Tolerance ◽

Water Content ◽

Water Status ◽

Field Capacity ◽

Total Protein Content ◽

Severe Drought ◽

Molecular Weights ◽

Potential Marker ◽

Relative Water

Dehydrins are proteins that play a role in the mechanism of drought tolerance. This study aimed at establishing dehydrin profile and accumulation in four local melon varieties of Iran: Mino, Dargazi, Saveii, and Semsori, as well as in a commercial variety Honeydew. Plants were treated with drought stress by adjusting the soil water content to 75, 50, 40, 30 and 20% of field capacity (FC) by withholding water. Water status of plants was monitored based on the seedling fresh weight (FW) and relative water content of leaves (RWC). Total protein content was extracted, then heat-stable protein (HSP) fraction was isolated for each variety and water stress treatment. After SDS-PAGE of HSP, Western blotting analysis was carried out with Anti-dehydrin rabbit (primary) and Goat anti rabbit (secondary) antibodies. ANOVA results showed that with decreasing FC below 75%, FW and RWC decreased, but these changes significantly varied among genotypes. On the basis of FW and RWC data under different drought stress treatments, the following drought-tolerant ranking was established: Mino > Dargazi > Saveii and Honeydew > Semsori, from tolerant to sensitive order. Results of Western blot analysis showed that expression of some proteins with molecular weights of 19–52 kDa was induced in the studied varieties under drought stress (% FC). Expression level of the dehydrin proteins in different varieties was variable and also depending on the drought stress level applied. However, dehydrin proteins (45 and 50 kDa) showed strong expression levels in all varieties under severe drought stress (20% FC). The abundance of dehydrin proteins was higher in tolerant varieties (Mino and Dargazi) than in moderate and drought sensitive genotypes. Consequently, dehydrins represent a potential marker for selection of genotypes with enhanced drought tolerance.

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The enhancement of drought tolerance for pigeon pea inoculated by arbuscular mycorrhizae fungi

Plant Soil and Environment ◽

10.17221/116/2011-pse ◽

2011 ◽

Vol 57 (No. 12) ◽

pp. 541-546 ◽

Cited By ~ 6

Author(s):

G. Qiao ◽

X.P. Wen ◽

L.F. Yu ◽

X.B. Ji

Keyword(s):

Drought Stress ◽

Drought Tolerance ◽

Arbuscular Mycorrhizae ◽

Soluble Sugar ◽

Lipid Peroxides ◽

Am Fungi ◽

Pigeon Pea ◽

Positive Effects ◽

Am Symbiosis ◽

Osmotic Solute

  Pigeon pea (Cajanus cajan) has been rapidly grown in the drought-striken Karst regions of southwest China. Present research aimed to investigate the effects of arbuscular mycorrhizae (AM) on the drought tolerance of pigeon pea, as well as to elucidate the physiological responses of AM-colonized seedlings to the water deficit. As subjected to drought stress, AM symbiosis (AMD) highly led to the positive effects on root system, plant height and stem diameter. AMD demonstrated a remarkably higher chlorophyll content, photosynthetic rate and stomatal conductance. The soluble sugar in AMD was significantly higher than that of the non-AM seedlings (NAMD), indicating the enhanced tolerance at least partially correlated with osmotic solute. Conversely, the proline (Pro) of AMD was lower, revealing the excessive Pro was not imperative for drought tolerance. After 30 days drought stress, AMD gave around a third less lipid peroxides than that of NAMD. Rather, the root activities of AMD were significantly higher than that of the latter after 10 days drought stress. Thereby, AM fungi might substantially elevate the tolerance to drought of pigeon pea, and the cumulative effects contributed to the enhanced tolerance. To date, this has been the first report concerning the enhancement of drought tolerance via AM colonization in this legume species.  

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Exopolysaccharides Producing Bacteria for the Amelioration of Drought Stress in Wheat

Sustainability ◽

10.3390/su12218876 ◽

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.

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