Alleviating Salinity Stress Research Articles

Ameliorative effects of seed treated with phytohormones on seedling growth, soluble protein content and antioxidant enzymes of hargel (Solenostemma argel Hayne) seedlings under salt stress

Salinity stress profoundly affects crop plants’ morphological structures and physiological processes, decreasing plant growth and development. The application of phytohormones has been proved an efficient way to alleviate salinity stress. This study was done to evaluate the effects of exogenous application of gibberellic acid (GA3; 0.288 mM), salicylic acid (SA; 0.362 mM), indole acetic acid (IAA; 0.285 mM) and control (0 mM) on seedling growth and physiological parameters of hargel (Solenostemma argel Hayne) seedlings under different salinity levels (0, 50 and 100 mM NaCl). Significant decreases due to salinity stress were observed in all the seedling growth parameters shoot and root length, shoot fresh weight, shoot dry weight, root fresh weight, root dry weight, chlorophyll a and b content, and antioxidant enzymes activities such as superoxide dismutase (SOD), peroxidase (POD), catalase (CAT), and ascorbate peroxidase (APX). In contrast, soluble protein and carotenoid content increased with increasing salinity. At high salinity level, GA3 increased carotenoid content and APX activity by 56.4% and 53.4%, respectively, while SA increased shoot dry weight, SOD, POD and soluble protein by 1.3-fold, 1.3-fold, 1.95-fold and 93.2%, compared with the control, IAA increased root length and fresh root weight at the same salinity level by 1.58-fold and 2-fold, respectively. In conclusion, seed priming with an appropriate dosage of exogenous hormones successfully mitigates the adverse effects of NaCl by increasing photosynthetic pigment, antioxidant enzyme activity and seedling growth parameters. Furthermore, SA exhibited the best mitigating effects compared to IAA and GA3.

The Role of Nano-selenium in Alleviating the Effects of Salt Stress in Date Palm Trees (Phoenix dactylifera L.): a Fourier Transform Infrared (FTIR) Spectroscopy Study

Fourier transform infrared (FTIR) spectroscopy was used to determine the biochemical changes in date palm leaves which induced different NaCl concentrations (2.5 (control), 5, 10 and 20 dS m−1). It was also used to determine the potential role of selenium nanoparticles (Se NPs) at concentrations of 80 and 160 ppm in alleviating salinity stress of date palm (Phoenix dactylifera L.) trees. Results showed the appearance of a new peak at 2850 cm−1 in the lipid region (2800–3000 cm−1) when date palm trees were exposed to salinity stress. This peak was not observed in the control treatment or when salinity was combined with foliar spraying of Se NPs. Furthermore, a clear and distinct peak at 1735 cm−1 was only seen in plants exposed at 10 or 20 dS m−1 salinity. This peak was attributed to membrane lipid compounds that contain carbonyl ester groups. In addition, the findings demonstrated that the treatments affected the secondary structure of proteins (1500–1800 cm−1) and carbohydrates (1200–1500 cm−1). This was evident by the appearance and disappearance of some characteristic peaks in these regions.

Funneliformis constrictum modulates polyamine metabolism to enhance tolerance of Zea mays L. to salinity

The mechanisms underlie increased stress tolerance in plants of salinity stress in plants by arbuscular mycorrhizal fungi (AMF) are poorly understood, particularly the role of polyamine metabolism. The current study was conducted to investigate how inoculation with the AMF, Funneliformis constrictum, affects maize plant tolerance to salt stress. To this end, we investigated the changes in photosynthesis, redox status, primary metabolites (amino acids) and secondary metabolism (phenolic and polyamine metabolism). Control and inoculated maize plants were grown using different concentrations of diluted seawater (0%, 10%, 20% and 40%). Results revealed that treatment with 10% seawater had a beneficial effect on AMF and its host growth. However, irrigation with 20% and 40% significantly reduced plant growth and biomass. As seawater concentration increased, the plants' reliance on mycorrhizal fungi increased resulting in enhanced growth and photosynthetic pigments contents. Under higher seawater concentrations, inoculation with AMF reduced salinity induced oxidative stress and supported redox homeostasis by reducing H2O2 and MDA levels as well as increasing antioxidant-related enzymes activities (e.g., CAT, SOD, APX, GPX, POX, GR, and GSH). AMF inoculation increased amino acid contents in shoots and roots under control and stress conditions. Amino acids availability provides a route for polyamines biosynthesis, where AMF increased polyamines contents (Put, Spd, Spm, total Pas) and their metabolic enzymes associated (ADC, SAMDC, Spd synthase, and Spm synthase), particularly under 40% seawater irrigation. Consistently, the transcription of genes, involved in polyamine metabolism was also up regulated in salinity-stressed plants. AMF further increased the expression in genes involved in polyamine biosynthesis (ODC, SAMDC, SPDS2 and decreased expression of those in catabolic biosynthesis (ADC and PAO). Overall, inoculation with Funneliformis constrictum could be adopted as a practical strategy to alleviate salinity stress.

Wheat plant –Plant Growth Promoting Rhizobacteria (PGPR) interaction to alleviate the salt stress in vitro and in vivo

The current work studied the mechanistic basis of salt tolerant PGPR bacteria in alleviating salinity stress in wheat.Two experiments were conducted at the Agricultural Research Center (ARC), 2021-2022, to evaluate the interaction between wheat var. Misr1 and two salt tolerant PGPR bacterial strains, Azospirillum (A.) brasilense NO40 and Bacillus thuringiensis (Bt) under saline conditions. The staining technique used to detect the colonization effectiveness of applied bacteria. Images of 30-day wheat seedlings were captured and subjected to the following measurements: root area, leaf area, root length, shoot length, and dark green color index (DGCI). TEM was used to look for bacterial colonization in wheat seedling. Chlorophyll, proline, peroxidase activity, rhizosphere dehydrogenase activity and electrical conductivity (EC) were all quantified. Results revealed that the wheat seedling roots inoculated with the salt tolerant bacterial strains produced a highly intense red colour. The colonized bacteria appeared on the outer surface of the root and intercellular space of root tissue. The data showed a significant rise in all measured parameters in the inoculated wheat seedlings with the salt tolerant bacterial strains compared to the non-inoculated wheat seedlings. Additionally, the wheat seedlings inoculated with a mixture of NO40 and Bt showed the best results as compared to that inoculated with only NO40 or with only Bt. Finally, EC values before and after planting with the inoculated wheat seeds revealed a decrease in the salinity of the soil rhizosphere (9.27 mmhos/cm vs. 5.1 mmhos/cm). In conclusion: Salt stress in wheat saline soils was alleviated by bacterial strains studied. Optimum results were obtained from the mixture of A. brasilense and Bt. Results must later be verified in field trials.

Silicon improves the effect of phosphate-solubilizing bacterium and arbuscular mycorrhizal fungus on phosphorus concentration of salinity-stressed alfalfa (Medicago sativa L.)

Under salinity stress, the availability of soil nutrients to plants is reduced, leading to disruption of nutrition and the balance of plant nutrients, including phosphorus (P). The use of phosphate-solubilizing microorganisms (PSM) and silicon (Si) in alleviating salinity stress and improving the uptake of P by plants has become a global solution. However, there is limited information on the effect of phosphate-solubilizing bacteria and arbuscular mycorrhizal fungi in the combination with Si on improving the absorption of P by plants including legumes under salinity stress. In this study, the plant growth-promoting potential of an effective phosphate-solubilizing bacterial strain (R115), Microbacterium shaanxiense, and an arbuscular mycorrhizal fungus, Claroideoglomus etunicatum, alone or in the combination with Si to alleviate salinity stress in alfalfa inoculated with its rhizobial symbiosis, Ensifer meliloti N44, and improve the absorption of P by this plant was investigated by a pot-experiment in a completely randomized design with factorial arrangement in three repetitions. Experimental treatments included: Si factor at two levels of 0 and 4 mM Si from potassium silicate source, bacterial strain R115 factor at two levels of B0 (control), and strain R115 (B1), mycorrhizal fungus factor at two levels of F0 (control) and mycorrhizal fungus (F1), and salinity (saline water) factor at three levels of 0, 5, and 15 dS m−1. Salinity stress reduced plant biomass, the content of chlorophyll, the concentration of N, P and K of plant and increased the concentration of Na in shoot tissue and the activity of antioxidant enzymes (catalase and superoxide dismutase) in alfalfa plant. However, the use of PSM (M. shaanxiense R115 and C. etunicatum) and Si improved the morphological and physiological characteristics of the plant, reduced the plant Na concentration, and increased the concentration of N, P, and K of alfalfa plants. The highest improvement in plant growth indices (shoot P concentration) was recorded in plants inoculated with PSM in the presence of Si. The results of this study showed that Si fertilization can be suggested as a sustainable strategy for improving the plant growth promoting effects of PSM on the growth of alfalfa (e.g., increased shoot P concentration) and encouraging ecological adaptability of this plant under saline water irrigation.

Magnetic Iron-Improved Growth, Leaf Chemical Content, Yield, and Fruit Quality of Chinese Mandarin Trees Grown under Soil Salinity Stress.

Chinese mandarin fruits are an inexpensive and rich source of vitamin C. They have potential benefits in treating acute respiratory infections and mitigating inflammation in critical patients with COVID-19. In Egypt, citrus is the most important fruit tree but is sensitive to salinity stress, resulting in poor vegetative tree growth and reductions in productivity and fruit quality. Magnetic iron has emerged as a promising approach in the citrus tree industry, since it improves vegetative growth, yield, and fruit quality and alleviates salinity stress in Chinese mandarin trees grown in soils suffering from high salt stress. This research is aimed at studying the influence of adding magnetic iron (as soil treatment) on tree canopy growth, yield, and fruit quality of 'Chinese' mandarin trees. Therefore, the treatments were as follows: 0, 250, 500, and or 750 g of magnetic iron.tree-1. Our results indicated that all applications of magnetic iron significantly improved tree canopy volume, leaf total chlorophyll, relative water content, yield (kg.tree-1), and the fruit physical and chemical characteristics of Chinese mandarin. In contrast, leaf Na and Cl content, (%), proline, and total phenolic content were decreased by magnetic iron soil treatments. In respect to vegetative growth, our results indicated that adding magnetic iron at the concentration 750 g.tree-1 caused the best values of tree canopy volume. A similar trend was noticed regarding yield. The increase in yield attained was nearly 19%; the best values were obtained when magnetic iron were used at 750 g.tree-1. In conclusion, the application of magnetic iron can lead to improved fruit production and fruit quality of Chinese mandarin trees grown in salinity stress conditions.

Sugar-terminated carbon-nanodots stimulate osmolyte accumulation and ROS detoxification for the alleviation of salinity stress in Vigna radiata

In recent times, nanotechnology has emerged as an efficient tool to manage the adverse effect of environmental stresses on plants. In this connection, carbon-nanodots (CNDs) have been reported to ameliorate the negative impacts of salinity stress. Further, surface modification of CNDs is believed to augment their stress-alleviating potential, however, very little has been known about the potential of surface-functionalized CNDs. In this purview, two sugar (trehalose and glucose) terminated CNDs (CNPT and CNPG) have been synthesized and assessed for their stress-alleviating effects on Vigna radiata (a salt-sensitive legume) seedlings subjected to different concentrations of NaCl (0, 50, and 100 mM). The synthesized CNDs (CNPT and CNPG) exhibited a hydrodynamic size of 20–40 nm and zeta potential of up to − 22 mV with a 5–10 nm core. These water-soluble nanomaterials exhibited characteristic fluorescence emission properties viz. orange and greenish-yellow for CNPT and CNPG respectively. The successful functionalization of the sugar molecules on the CND cores was further confirmed using FTIR, XRD, and AFM. The results indicated that the application of both the CNDs improved seed germination, growth, pigment content, ionic and osmotic balance, and most importantly, the antioxidant defense which decreased ROS accumulation. At the same time, CNPT and CNPG exhibited no toxicity in the Allium cepa root tip bioassay. Therefore, it can be concluded that sugar-terminated CNDs improved the plant responses to salinity stress by facilitating sugar uptake to the aerial part of the seedlings.

Nitrogen enriched chemically produced carbon supplementary impacts on maize growth under saline soil conditions

Poor organic matter and nitrogen (N) deficiency along with salinity in arid and semiarid region soils are major hurdles to optimization of cereal's yield. In different cereals, maize productivity is significantly decreased due to less availability of N in low organic matter soils. Scientists suggest the incorporation of organic fertilizers to overcome this issue. That’s why the current study was conducted to explore the effectiveness of chemically produced nitrate blended acidified carbon (NBC). There were 3 levels of NBC i.e., 0, 0.50 and 1.00% applied under naturally normal and saline soils having EC 2.75 and 6.19 dS/m respectively. Results showed that the addition of 1.00NBC was significantly better compared to 0NBC for improvement in maize growth attributes i.e., root (32.86 and 77.84%) and shoot (74.17 and 67.57%) length, shoot fresh (53.98 and 97.42%) and dry weight (53.20and 84.20%), root dry (45.97 and 53.66%) and fresh weight (45.62 and 25.14%) in normal and saline conditions respectively. A significant enhancement in chlorophyll a, b, total and carotenoids of maize leaves also validated the imperative role of 1.00NBC than 0NBC in saline and normal soil. Application of 1.00BC also significantly decreases leaves electrolyte leakage and Na concentration in root and leaves over 0NBC in saline soils. In conclusion, 1.00NBC is an effective amendment to improve maize growth in saline soil. More investigations are suggested on different cereal crops under variable agroclimatic zones to declare 1.00NBC as the most effective amendment for alleviation of salinity stress.

Foliar application of thiourea, salicylic acid, and kinetin alleviate salinity stress in maize grown under etiolated and de-etiolated conditions

Salinity stress and the absence of light negatively impact growth and development of the plants. Morpho-physiological and biochemical attributes of maize (Zea mays L.) get severely affected by salt stress and subdue light. Therefore, a pot experiment was conducted under the prevailing environmental conditions of Turbat, Balochistan, to explore etiolation and the de-etiolation response of maize hybrid (SP-17S23) to salinity stress under exogenous application of plant growth regulators (PGRs). Maize seedlings in three sets, i.e., non-etiolated, etiolated, de-etiolated, subjected to salinity stress (120 mM NaCl) after 15 days of seed germination. After a week, the seedlings were sprayed with optimized levels of different PGRs, including thiourea (TU; 10 mM), salicylic acid (SA; 250 µM), and kinetin (KIN; 3 µM). Salinity stress hampered plant growth and affected morpho-physiological attributes. However, PGRs foliar treatment proved effective, thus ameliorating the impact of salinity and etiolation on maize seedlings. Growth attributes (root/shoot length, leaf area, root/shoot fresh and dry weight), photosynthetic pigments (Chl a, b and carotenoids) were significantly enhanced under the foliar treatment of PGRs, especially under TU and KIN treatments. However, the oxidative damage parameters, i.e., malondialdehyde (MDA) and hydrogen peroxide (H2O2), decreased under the treatment of PGRs, thereby protecting seedlings under salinity and etiolated conditions. Overall, PGRs enhanced tolerance potential of plants under salinity stress with the consideration of light variations remain the key concern for developing healthy and vigor seedling strands.

Endophytic Candida membranifaciens from Euphorbia milii L. Alleviate Salt Stress Damages in Maize

Fungal endophytes are not widely known for their role in bioactive metabolite production and salinity stress alleviation in different crop plants. Presently, we investigated the salt stress (NaCl, KCl, and H2SO4) mitigation capabilities of fungal endophyte Candida membranifaciens (FH15) isolated from Euphorbia milii L. The pure culture filtrate (CF) of C. membranifaciens revealed siderophore production and solubilization of phosphate, with high levels of indoleacetic acid (IAA: 35.8µg/mL), phenolics (70 µg/mL), and flavonoids (50 µg/mL) by using a UV spectrophotometer. The LC/MS analysis of the CF showed different phenols and flavonoids that were identified as Salicylic acid, Baicalein, Aconitic acid, Feruloylquinic acid, Coniferyl aldehyde hexoside, Pentose, Chlorogenic acid, Myricetin, Propoxyphene, and Amino-flunitrazepam. Inoculation of maize seedlings with C. membranifaciens significantly (p = 0.05) enhanced the fresh and dry biomass, carotenoid, and chlorophyll contents under 100 mM salt stress conditions. Similarly, the catalase, peroxidase activity, phenols, proline flavonoids and relative water contents (RWC) of the maize plants were enhanced. More interestingly, the inoculation of C. membranifaciens on maize revealed a higher endogenous IAA level as compared to non-inoculated control plants. Endophyte C. membranifaciens inoculation on maize seedlings under salt stress revealed a 20.87% and 16.60% increase in fresh and dry biomass, as well as significantly enhanced root shoot length and allied growth attributes, in addition to an alleviation of the adverse effects of salinity stress. Conclusively, endophytic C. membranifaciens significantly enhanced the growth attributes of maize and mitigated the adverse effects of salinity stress. Such endophytic fungal strain could be used for further field trails to enhance agricultural productivity and facilitate sustainable agricultural practices.

Riboflavin Seed Priming Activates OsNHXs Expression to Alleviate Salinity Stress in Rice Seedlings

Riboflavin Seed Priming Activates OsNHXs Expression to Alleviate Salinity Stress in Rice Seedlings

Synergistic effects of mycorrhizae and seaweed extracts in alleviating salinity stress in ‘Anna’ apples

Synergistic effects of mycorrhizae and seaweed extracts in alleviating salinity stress in ‘Anna’ apples

Understanding the mechanism of action of stress-acclimatized rhizospheric microbiome towards salinity stress mitigation in Vigna radiata: A focus on the emission of volatiles

Microbiome-based rhizospheric engineering has emerged as a promising approach towards attaining agricultural sustainability. While the top-down approach of acclimatizing the rhizospheric microbiome to stressors is relatively easy to perform, the mechanisms involved in plant growth promotion by directed evolution are yet to be understood. The present study aimed to understand the mechanism of stress management by a salt stress-acclimatized microbiome, generated through indirect plant-mediated selection over multiple plant ( Vigna radiata ) growth cycles, with a focus on the emission of volatile compounds. A culture bank was generated by isolation of bacterial strains from the stress-acclimatised microbiome, using group-specific media. Characterization of the strains was performed by examining their potential plant growth-promoting (PGP) traits followed by phylogenetic affiliation using 16S rRNA sequencing. The strains exhibited strong tolerance to salinity stress when grown on artificial root exudate medium and V8 medium, at different salt concentrations. Based on PGP scoring, the eleven best performing bacterial strains were assessed for their ability to impact plant morphology and growth attributes in a split plate assay allowing only volatile compounds to be exchanged, using Arabidopsis as a model plant. An alteration in the seedling morphology of Arabidopsis was observed due to the production of volatile bioactive compounds by some of the strains. To delineate the specific volatiles produced by the bacterial strains responsible for such an impact on Arabidopsis seedlings, the volatiles emitted by selected strains were collected and analyzed by GC-MS. A correlation could be drawn between the specific volatiles produced by key bacterial members of the acclimatized microbiome e.g. Bacillus haynesii, Pseudomonas monteilii and Ochrobactrum soli , and their contribution towards alleviation of salinity stress in A. thaliana . A detailed analysis of the volatilomes emitted by stress-acclimatized bacterial strains revealed the identity of crucial metabolites, for instance hydrocarbons like 7 methyl-hexadecane, 2-(2-butoxyethoxy) ethanol or sulfur containing volatiles, which could at least partially contribute to plant growth promotion and stress tolerance. This work opens up new avenues for rhizospheric engineering as a way towards more resilient and sustainable crop production. • Mode of action of engineered microbiome in stress mitigation revealed. • Strains with multi-PGP traits were identified from stress-acclimatized microbiome. • Bacteria exhibited salinity stress tolerance and growth promotion in Arabidopsis . • Volatiles’ importance in stress mitigation by acclimatised microbiome highlighted. • Key volatiles mediating growth promotion and stress tolerance were identified.

Seeds priming with ß-aminobutyric acid alleviated salinity stress of chickpea at germination and early seedling growth

Salinity stress is one of the most prevalent environmental factors that severely affect seed germination, early growth stages, and crop production. The present study was carried out to evaluate the protective role of β-aminobutyric acid (BABA) in alleviating salt stress in chickpea (Cicer arietinum L.) varieties (Jabel Marra, Porgeg and Shendi) under four concentrations of NaCl solutions (0, 50, 100, and 150 mM NaCl). Three levels of β-aminobutyric acid (0, 0.25, and 0.50 mM) were applied. Germination and seedling attributes were measured. A high level of salinity (150 mM NaCl) increased mean germination time by 10.0% and decreased the coefficient velocity of germination and root dry weight by 12.1% and 96.2%, respectively, compared with the control. ‘Jabel Marra’ significantly surpassed other studied varieties in germination characters, while at seedling growth, ‘Shendi’ outperformed other varieties in root and shoot length, fresh, and dry weights. Seeds treated with 0.25 mM BABA caused increment on water uptake by 18.1% compared with 0.0 mM BABA. At 150 mM NaCl, seeds primed with 0.50 mM BABA increased the germination percentage of ‘Jabel Marra’ and ‘Porgeg’ by 6.3% and 11.9% as compared with 0.0 mM BABA. Under 50 mM NaCl and 0.50 mM BABA, root length, shoot length, shoot fresh weight, and root dry weight were increased by 170.6%, 44.8%, 80%, and 49.3%, respectively, relative to 0.0 mM BABA. The present study results suggested that seed priming by BABA could be useful to alleviate the salinity stress of chickpea at germination and early seedling growth.

Effects of Different Organic Amendments on Maize (Zea Mays L.) Growth in Salt Affected Soil

Salinity stress is the most notorious among all abiotic stresses. It hampers the growth and productivity of crops via ionic imbalance, disturbance in the metabolic process and specific ions toxicity. The necessity of time is to introduce better organic amendment rates for its mitigation in cereal crops, especially maize. Therefore, a pot experiment was performed in the wirehouse of the Saline Agriculture Research Centre (SARC), University of Agriculture, Faisalabad to evaluate the effect of farmyard manure and compost application rates in saline soil. A hybrid maize variety (Monsanto DK-6789) was sown and recommended doses of NPK were applied. Organic amendments (FYM and Compost) with their rates (recommended, 25% increased dose of recommended and 50% increased dose of recommended) were applied to assess the growth of hybrid maize with salinity levels (Control < 2dS m-1, moderate salinity_5dS m-1, High salinity_10dS m-1). Seven treatments each with three replicates were carried out by using Complete Randomized Design (CRD). The results of the study indicated that T4 (50% increased farmyard manure) and T7 (50% increased compost) were significantly varied in controlling the shoot and root length, shoot and root fresh weight and dry weight of maize over control at <2, 5 and 10 dS m-1 EC. A significant increase of 32, 28 and 39% in chlorophyll contents of maize validated the efficacious functioning of T4 over control for alleviation of <2, 5 and 10 dS m-1 salinity. Similarly, significant enhancement of 48, 39 and 84% in root fresh weight also declared that T7 was a better treatment under <2, 5 and 10 dSm-1 salinity. In conclusion, T4 and T7 can be used and recommended for better alleviation of salinity stress in maize. More experiments are suggested at the field level by using these 2 application rates of farmyard manure and compost for declaration of modified amendment for salinity stress mitigation.

Role of composted organic material in reducing hazardous effect of salinity stress on biological nitrogen fixation and plant growth in salt affected soils of arid region

Application of organic matter (OM) has shown positive effects on growth and yield of crop grown under soil salinity stress. The present study was conducted to estimate effectiveness of OM in enhancing Biological Nitrogen Fixation (BNF) in soil and in return improving growth and yield of cowpea. Therefore, role of (OM) in alleviating impact of salinity stress on (BNF) in soils of arid region was evaluated in medium textured soils of different content of salts content. Experiment was conducted in pots under greenhouse conditions. Salinity range studied was 3.5, 8.2 and 12.4 dSm-1 in J1, J2, and J3 soil respectively. Compost as OM was added at 15, 25 and 50 g Kg-1 soil. Cowpea local variety was used as a test crop. Total nitrogen in soils without the addition of organic matter after harvesting was the least at the highest salinity level and the highest was in the soil of the least salinity level. Number of root nodules reduced by 27.0% and 49.0% when soil salinity increased to 8.2 and 12.4 dSm-1, respectively, compared to that in soil of 3.5 dSm-1. Total N in Cowpea plant linearly increase with the increase of level of (OM) addition. Rate of Increase in total N was the highest at the lowest salinity level soil and was the least at the highest salinity level soil. Weight of root nodules decreased by 45% when soil salinity increased by 42%. Addition of OM at a rate of 25 g OM Kg-1 soil to J1 soil of (3.5 dSm-1) and soil J3 of 12.4 dSm-1 weight of root nodules increased by 47.0%. and 21.7%, respectively. Dry weight of Cowpea plant grown in the three soils received different levels of OM decreased with the increase of soil salinity irrespective of level of OM addition. Addition of OM at a rate of 15, 25, and 50 g kg-1 soil of 3.5 dSm-1 seed yield increased by 65%,130%, and 136% respectively. These results had confirmed the role of OM in alleviating salinity stress on BNF process in soil.

Salinity of irrigation water selects distinct bacterial communities associated with date palm (Phoenix dactylifera L.) root

Saline water irrigation has been used in date palm (Phoenix dactylifera L.) agriculture as an alternative to non-saline water due to water scarcity in hyper-arid environments. However, the knowledge pertaining to saline water irrigation impact on the root-associated bacterial communities of arid agroecosystems is scarce. In this study, we investigated the effect of irrigation sources (non-saline freshwater vs saline groundwater) on date palm root-associated bacterial communities using 16S rDNA metabarcoding. The bacterial richness, Shannon diversity and evenness didn’t differ significantly between the irrigation sources. Soil electrical conductivity (EC) and irrigation water pH were negatively related to Shannon diversity and evenness respectively, while soil organic matter displayed a positive correlation with Shannon diversity. 40.5% of total Operational Taxonomic Units were unique to non-saline freshwater irrigation, while 26% were unique to saline groundwater irrigation. The multivariate analyses displayed strong structuring of bacterial communities according to irrigation sources, and both soil EC and irrigation water pH were the major factors affecting bacterial communities. The genera Bacillus, Micromonospora and Mycobacterium were dominated while saline water irrigation whereas contrasting pattern was observed for Rhizobium, Streptomyces and Acidibacter. Taken together, we suggest that date-palm roots select specific bacterial taxa under saline groundwater irrigation, which possibly help in alleviating salinity stress and promote growth of the host plant.

Focus on the Role of the Abiotic Environment on Interactions Between Plants and Microbes.

Interactions between plants and microbes are shaped by the physical world that surrounds them. In nature, the abiotic environment is complex, and factors such as nutrient and water availability, humidity, wind, carbon dioxide levels, salt, pollutants, and temperature all affect the growth and physiology of plants and microbes as well as their interactions. Much of our mechanistic understanding of plant-microbe interactions comes from experiments done in carefully controlled conditions. This Focus Issue looks at how aspects of the abiotic environment affect these plant-microbe interactions, and, conversely, how plant-microbe interactions affect host response to abiotic stress.[Formula: see text] The author(s) have dedicated the work to the public domain under the Creative Commons CC0 "No Rights Reserved" license by waiving all of his or her rights to the work worldwide under copyright law, including all related and neighboring rights, to the extent allowed by law, 2022.Additional content is available on the Focus on the Role of the Abiotic Environment on Interactions Between Plants and Microbes.Complete Genome Sequence of Curtobacterium sp. C1, a Beneficial Endophyte with the Potential for In-Plant Salinity Stress AlleviationProteasomal Degradation of JAZ9 by Salt- and Drought-Induced Ring Finger 1 During Pathogen Infection.

Nitric oxide mediated regulation of ascorbate-glutathione pathway alleviates mitotic aberrations and DNA damage in Allium cepa L. under salinity stress

Allium cepa L. is an important medicinal and food plant enormously affected by salinity in terms of its growth and quality. This experiment investigates ameliorative potential of NO donor sodium nitroprusside (SNP) on chromosomal aberrations and physiological parameters in A. cepa L. roots exposed to salinity stress. Roots with different concentrations of NaCl (25, 50, and 100 mM) alone, and in combination with 100 µM SNP were analyzed for mitotic aberrations, DNA damage, proline, malondialdehyde (MDA) content, and ascorbate-glutathione (AsA-GSH) cycle after 120 h of salinity treatments. Results revealed that salinity stress increased chromosomal aberrations, MDA, proline accumulation, and severely hampered the AsA-GSH cycle function. The comet assay revealed a significant (p ≤ 0.05) enhancement in tail length (4.35 ± 0.05 µm) and olive tail moment (3.19 ± 0.04 µm) at 100 mM NaCl exposure. However, SNP supplementation decreased total percent abnormalities, while increased the prophase, metaphase, anaphase, and telophase indexes. Moreover, ascorbate peroxidase and glutathione reductase activities increased with AsA/DHA and GSH/GSSG ratios, respectively. Results suggest that SNP supplementation alleviates salinity stress responses by improving AsA-GSH cycle and proline accumulation. Based on present findings, NO supplementation could be recommended as a promising approach for sustainable crop production under salinity stress.

Role of Brassinosteroids in plants responses to salinity stress: A review

Brassinosteroid emerges as an essential phytohormone that helps the plant to maintain plant growth and development. It also helps the plants grow well under adverse conditions along with normal conditions. In this review article, we have discussed the functional role of brassinosteroid (BRS) in plants under salinity stress conditions. Salinity stress is one of the most devastating abiotic stresses which adversely affect plant growth by disturbing their metabolic pathway. This article also comprises the occurrence, structure and signalling pathway of the brassinosteroid. Application of brassinosteroid improves the plant status under salinity by enhancing the antioxidant enzyme activity in plants. Moreover, we also reported the different growth parameters enhanced by brassinosteroid application in plants under salinity. BRSs also maintain plant growth through the regulation of expression of various genes whose products are involved in various biochemical and physiological processes. This review is based on the various aspects in much detail which are required to understand the proper mechanism of BRS, such as i) the role of BRS signaling pathways in providing tolerance to the plants, ii) changes due to the presence or absence of BRS in plants under stress conditions, iii) BRSs application on the regulation of different genes and transcriptional factor, iv) regulation in ion homeostasis, v) reduction of oxidative stress via different mechanisms under salinity stress. However, a lot of knowledge is required to understand the role of BRS in alleviating salinity stress and needs future research work on BRS with its different derivatives in the alleviation of salt stress.