Salt-stressed Plants Research Articles

The Roles of Calcineurin B-like Proteins in Plants under Salt Stress

Salinity stands as a significant environmental stressor, severely impacting crop productivity. Plants exposed to salt stress undergo physiological alterations that influence their growth and development. Meanwhile, plants have also evolved mechanisms to endure the detrimental effects of salinity-induced salt stress. Within plants, Calcineurin B-like (CBL) proteins act as vital Ca2+ sensors, binding to Ca2+ and subsequently transmitting signals to downstream response pathways. CBLs engage with CBL-interacting protein kinases (CIPKs), forming complexes that regulate a multitude of plant growth and developmental processes, notably ion homeostasis in response to salinity conditions. This review introduces the repercussions of salt stress, including osmotic stress, diminished photosynthesis, and oxidative damage. It also explores how CBLs modulate the response to salt stress in plants, outlining the functions of the CBL-CIPK modules involved. Comprehending the mechanisms through which CBL proteins mediate salt tolerance can accelerate the development of cultivars resistant to salinity.

Colonization of Satureja hortensis L. (Summer savory) with Trichoderma harzianum alleviates salinity stress via improving physio-biochemical traits and biosynthesis of secondary metabolites

Salinity as the main abiotic stress, influences plant growth, yield, and productivity, especially in arid and semi-arid areas of the world. Researchers are increasingly turning to biological strategies to improve crop tolerance to high salinity levels, such as using endophytic fungus. This study aimed to evaluate the morphological, physiological, and biochemical responses of Summer savory (Satureja hortensis L., Lamiaceae) plants to inoculation with Trichoderma harzianum (an endophytic fungus) under various levels of salinity (0, 50, 100, and 150 mM NaCl) in a pot-based experiment. The results showed that Summer savory inoculated with T. harzianum exhibited improved growth compared with salt-stressed and non-stressed plants (up to 93.47%). Furthermore, inoculation with T. harzianum caused a restoration in the content of chlorophyll a, b, and carotenoids up to 1.47-fold. Both non-enzymatic and enzymatic antioxidants were enhanced in the presence of salt stress, and T. harzianum further increased their level, approximately up to 66.67%. Salinity caused an obvious increase in hydrogen peroxide, malondialdehyde, and electrolyte leakage (up to 3.04-fold), but their content began to decline when the plants were inoculated with T. harzianum (with reduction factor up to 41.43%). Additionally, T. harzianum-inoculated plants maintained higher levels of proline, total soluble sugar content (up to 1.46-fold), and volatile organic compounds compared with control and salt-stressed plants. Overall, the findings of this study suggest that inoculation with T. harzianum can enhance the salt tolerance of S. hortensis by improving growth via modulation of biochemical, physiological, and secondary metabolites biosynthesis. Therefore, T. harzianum may be a promising biological strategy for improving crop productivity under saline conditions.

Exogenous citric acid improves growth and yield by concerted modulation of antioxidant defense system in brinjal (Solanum melongena L.) under salt-stress

Brinjal is sensitive to salinity, a common factor responsible for reducing its biomass and yield components. Recent research has demonstrated that citric acid/citrates can provide abiotic stress resistance in plants. In this study, Brinjal variety Pusakranti was treated with four concentrations of CA at 0, 100, 200, and 300 ppm applied foliarly under two levels of salt stress (0 mM and 60 mM NaCl) during spring 2021 with four replication per treatment. Salt stress reduced plant growth and yield attributes, pigments as well as metabolites in plants. Antioxidant enzyme activities of the plant increased compared to the non-stressed plants. While 300 ppm CA concentrations oenhanced the shoot and root fresh biomass (75 % and 71.8 %) and dry biomass (82.5 % and 40.7 %), while 200 ppm CA application increased the fruits count by 50 %, fruit diameter by 49 % and leaf photosynthetic pigments by 61 % compared to only salt-stressed plants. Similarly, CA application enhanced the antioxidants both enzymatic and non-enzymatic such as catalase by 42 %, peroxidase by 66 %, superoxide dismutase by 44 %, polyphenol oxidase by 50 % and Glutathione peroxidase by 37 % compared to only salt stressed plants. Furthermore, 300 ppm CA application also promoted the content of primary metabolites such as total protein content by 75 % and total free amino acids by 32 % as well as improvement in secondary metabolites such as total phenols by 31 % and flavonoids by 96 % compared to only salt treated plants. Overall, the above described results suggested that the foliarly applied CA(200 ppm) is a proficient approach which effectively counteract salt stress in brinjal by improving plant biomass, pigments, primary and secondary metabolites as well as modulating the the antioxidant defense system of the studied plant.

Regulatory effects of Hemin on prevention and rescue of salt stress in rapeseed (Brassica napus L.) seedlings

BackgroundSalt stress severely restricts rapeseed growth and productivity. Hemin can effectively alleviate salt stress in plants. However, the regulatory effect of Hemin on rapeseed in salt stress is unclear. Here, we analyzed the response and remediation mechanism of Hemin application to rapeseed before and after 0.6% (m salt: m soil) NaCl stress. Experiment using two Brassica napus (AACC, 2n = 38) rapeseed varieties Huayouza 158R (moderately salt-tolerant) and Huayouza 62 (strongly salt-tolerant). To explore the best optional ways to improve salt stress resistance in rapeseed.ResultsOur findings revealed that exogenous application of Hemin enhanced morph-physiological traits of rapeseed and significantly attenuate the inhibition of NaCl stress. Compared to Hemin (SH) treatment, Hemin (HS) significantly improved seedlings root length, seedlings height, stem diameter and accumulated more dry matter biomass under NaCl stress. Moreover, Hemin (HS) significantly improved photosynthetic efficiency, activities of antioxidant enzymes such as superoxide dismutase (SOD), peroxidase (POD), ascorbate peroxidase (APX), and decreased electrolyte leakage (EL) and malondialdehyde (MDA) content, thus resulting in the alleviation of oxidative membrane damage. Hemin (HS) showed better performance than Hemin (SH) under NaCl stress.ConclusionHemin could effectively mitigate the adverse impacts of salt stress by regulating the morph-physiological, photosynthetic and antioxidants traits of rapeseed. This study may provide a basis for Hemin to regulate cultivated rapeseed salt tolerance and explore a better way to alleviate salt stress.

Chemical Interventions to Alleviate Salt Stress in Cotton Plants: A Review

The alleviation of salt stress in cotton plants through the application of exogenous chemicals has emerged as a viable strategy to mitigate the adverse effects on various plant attributes, including growth, development, yield, and flowering. Plant hormones, known for their efficacy at low doses, have garnered significant attention in this context. Despite being inherently susceptible to salt stress, cotton plants experience severe impediments in water absorption from the soil, leading to delayed growth and development. Several phytohormones, including jasmonic acid, salicylic acid, and glycine betaine, have been extensively investigated in numerous studies for their potential to ameliorate salt stress in cotton plants. Promising results have been obtained with both foliar and seed treatments employing these substances. This foundational knowledge has paved the way for the development of alternative strategies to mitigate salt stress. However, the practical utilization of these chemicals is hindered by their elevated cost. Plant growth regulators, such as nitric oxide and melatonin, have also garnered interest for their ability to alleviate salt stress in cotton plants. Numerous studies have corroborated their effectiveness in this regard. This review comprehensively examines the aforementioned substances and extracts that have been investigated for their potential to mitigate the detrimental effects of salt stress on cotton plants.

Ensifer sp. GMS14 enhances soybean salt tolerance for potential application in saline soil reclamation

Rhizosphere microbiomes play an important role in enhancing plant salt tolerance and are also commonly employed as bio-inoculants in soil remediation processes. Cultivated soybean (Glycine max) is one of the major oilseed crops with moderate salt tolerance. However, the response of rhizosphere microbes me to salt stress in soybean, as well as their potential application in saline soil reclamation, has been rarely reported. In this study, we first investigated the microbial communities of salt-treated and non-salt-treated soybean by 16S rRNA gene amplicon sequencing. Then, the potential mechanism of rhizosphere microbes in enhancing the salt tolerance of soybean was explored based on physiological analyses and transcriptomic sequencing. Our results suggested that Ensifer and Novosphingobium were biomarkers in salt-stressed soybean. One corresponding strain, Ensifer sp. GMS14, showed remarkable growth promoting characteristics. Pot experiments showed that GMS14 significantly improved the growth performance of soybean in saline soils. Strain GMS14 alleviated sodium ions (Na+) toxicity by maintaining low a Na+/K+ ratio and promoted nitrogen (N) and phosphorus (P) uptake by soybean in nutrient-deficient saline soils. Transcriptome analyses indicated that GMS14 improved plant salt tolerance mainly by ameliorating salt stress-mediated oxidative stress. Interestingly, GMS14 was evidenced to specifically suppress hydrogen peroxide (H2O2) production to maintain reactive oxygen species (ROS) homeostasis in plants under salt stress. Field experiments with GMS14 applications showed its great potential in saline soil reclamation, as evidenced by the increased biomass and nodulation capacity of GMS14-inoculated soybean. Overall, our findings provided valuable insights into the mechanisms underlying plant-microbes interactions, and highlighted the importance of microorganisms recruited by salt-stressed plant in the saline soil reclamation.

A wheat WRKY transcription factor TaWRKY17 enhances tolerance to salt stress in transgenic Arabidopsis and wheat plant.

WRKY transcription factors are essential to plant growth, development, resistance, and the regulation of metabolic pathways. In this study, we characterized TaWRKY17, a WRKY transcription factor from wheat, which was differentially expressed in various wheat organs and was up-regulated by salt, drought, hydrogen peroxide (H2O2) and abscisic acid (ABA) treatment. To analyze TaWRKY17 function under salt stress, we obtained stable T3 generation transgenic Arabidopsis and wheat TaWRKY17 overexpression plants. TaWRKY17 overexpression in Arabidopsis and wheat caused a significant plant salt-stress tolerance enhancement. Under salt stress, superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT) enzyme activities were elevated in transgenic Arabidopsis and wheat plants compared with the wild type (WT), whereas H2O2 and malondialdehyde (MDA) accumulation was reduced in the transgenic lines. Moreover, ABA/reactive oxygen species (ROS)-related, and stress-response genes were regulated in the transgenic wheat plants, increasing tolerance to salt stress. The transgenic wheat plants were highly sensitive to ABA during seed germination and early seedling growth. In addition, TaWRKY17 virus-induced gene silencing (VIGS) decreased salt tolerance. These results showed that TaWRKY17 enhances salt tolerance by regulating ABA/ROS-related, and stress-response genes and increasing anti-oxidative stress capabilities. Therefore, this gene could be a target for the genetic modification of wheat.

Nitric oxide and hydrogen sulfide alleviates salt incited oxidative stress in Coriandrum sativum L

Soil salinity accelerates osmotic, ionic and oxidative pressure that suppresses plant growth and crop production. The objective of of the present investigation was to analyse protective function of nitric oxide (NO) and hydrogen sulfide (H2S) against salt (NaCl) stress in coriander plants. Different morphological, biochemical parameters, enzymatic and non-enzymatic antioxidants were analysed. Exposure of Coriandrum sativum L. to NaCl reduced length of root and shoot, biomass, relative water content and biochemical attributes. Exogenous use of SNP and NaHS individually or in combined treatment increased all the above-mentioned growth variables and inhibited NaCl incited biochemical alterations and oxidative damages in Coriandrum sativum L. Synergistic treatment (SNP + NaHS) exhibited increase in the morphological parameters, pigment and osmolyte contents. The oxidative stress biomarkers, hydrogen peroxide and superoxide generation were declined by SNP and NaHS as evidenced by reduced peroxidation of lipids. Activities of both glyoxylase as well as antioxidant enzymes were enhanced with presence of SNP and NaHS. Coriander seedlings treated with NaCl + SNP + NaHS exhibited 21 %, 7 %, 31 % and 59 % increase in superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APX), glutathione reductase (GR), respectively over NaCl treated plants. Level of methylglyoxal was decreased in Coriandrum sativum with rise in glyoxalase I and II enzymes. Therefore, synergistic supplementation of NO and H2S alleviates salt stress in coriander plants more efficiently than individual treatment and it might be because of crosstalk mechanism that facilitate salt stress resistance in plants.

Can salt-adapted microorganisms alleviate salt stress in plants and enhance their non-specific resilience?

Global climate change presents various challenges to agricultural biotechnology in developing crops with increased resilience to various adverse natural conditions. Given the importance of this problem, we explored the mechanisms of plant salt tolerance and the role of plant-associated microbes, in mediating important physiological and metabolic processes that increase plant resistance to salt stress. Understanding the physiological, metabolic, and molecular responses of the entire plant holobiont, primarily including microorganisms, to the combination of abiotic stresses may be the key to developing more effective methods of combating various stress conditions and increasing agricultural efficiency. This work encompassed 86 peer-reviewed articles focused on various aspects of plant development in saline conditions and especially on key mechanisms of mitigating stress conditions, including the role of rhizobiome and endophytic microorganisms. It is shown that host plants and various microorganisms can form complex relationships where each organism plays a specific role in forming tolerance to stress conditions. Our review proposes that studying microorganisms that are resistant to soil salinity can lead to the development of new strategies to combat salinization and improve crop stress resistance. The paper concludes that using salt-adapted biostimulant microorganisms, which are natural components of agricultural plant microbiomes, is a highly promising research area.

Application of GC7 to reduce hypusination via inhibiting deoxyhypusine synthase in Arabidopsis thaliana seedlings exposed salt stress

Salt stress is one of the most harmful stress types affecting our agriculture and food safety. Despite the extensive knowledge of plant responses induced by salt stress, the details of the regulation of metabolite-dependent posttranslational modifications occurring during salt stress have rarely been investigated. Hypusination is polyamine-dependent posttranslational modification of eukaryotic translation factor 5A (eIF5A), which is conserved in all living organisms. Some evidence suggests that this modification plays an important role in salt stress tolerance, but the significance of the enzymes participating in the synthesis of hypusine is unknown. GC7 (N1-guanyl-1,7-diaminoheptane) is a special compound which can inhibit the enzyme activity of deoxyhypusine synthase (DHS). In our study, we applied GC7 in order to examine the applicability and efficiency of this compound and to decipher the modulation of polyamine metabolism during salt stress in plants. Our results support the significance of DHS during salt stress and of GC7 as an efficient tool to study hypusination in plant species.

Comparative efficacy of different salt tolerant rhizobial inoculants in improving growth and productivity of Vigna radiata L. under salt stress

Worldwide, salinity severely affects agricultural production of crops such as mung bean in arid and semi-arid regions. In saline conditions, various species of Rhizobium can be used to enhance nodulation and induce salinity tolerance in maize. The present study conducted a pot experiment to determine the efficiency of three rhizobial isolates under different salinity conditions, such as 1.41, 4 and 6 dS m−1, on mung bean growth parameters, antioxidant status and yield. Results revealed that salt stress imparted adverse effects on the growth, antioxidants, yield and nodulation of mung bean. Under high salt stress conditions, fresh weights were reduced for roots (78.24%), shoots (64.52%), pods (58.26%) and height (32.33%) as compared to un-inoculated control plants. However, an increase in proline content (46.14%) was observed in high salt stressed plants. Three Rhizobium isolates (Mg1, Mg2, and Mg3), on the other hand, mitigated the negative effects of salt stress after inoculation. However, effects of Mg3 inoculation were prominent at 6 dS m−1 and it enhanced the plant height (45.10%), fresh weight of shoot (58.68%), root (63.64%), pods fresh weight (34.10%), pods number per plant (92.04%), and grain nitrogen concentration (21%) than un-inoculated control. Rhizobium strains Mg1, and Mg2 expressed splendid results at 1.41 and 4 dS m−1 salinity stress. The growth promotion effects might be due to improvement in mineral uptake and ionic balance that minimized the inhibitory effects caused by salinity stress. Thus, inoculating with these strains may boost mung bean growth and yield under salinity stress.

Plant growth-promoting endophytic fungi of the wild halophytic rice Oryza coarctata

BackgroundPlant growth-promoting endophytic fungi (PGPEF) that are associated with halophytes have the potential to boost crop salinity tolerance and productivity. This in turn has the potential of enabling and improving cultivation practices in coastal lands affected by salt stress.MethodsEndophytic fungi from the wild halophytic rice Oryza coarctata were isolated, characterized, identified, and studied for their effects on all developing stages of rice plant growth and their yields both with and without salt stress.Key resultsIn this study, three different fungal endophytes were isolated from the halophytic wild rice Oryza coarctata. Two isolates were identified as Talaromyces adpressus (OPCRE2) and Talaromyces argentinensis (OPCRh1) by ITS region sequencing. The remaining isolate NPCRE2 was confirmed as a novel strain named Aspergillus welwitschiae Ocstreb1 (AwOcstreb1) by whole genome sequencing. These endophytes showed various plant growth-promoting (PGP) abilities in vitro (e.g., IAA, ACC-deaminase and siderophore production, phosphate, and zinc solubilization as well as nitrogen fixation), where AwOcstreb1 was significantly more efficient compared to the other two isolates at high salinity (900 mm). Independent application of these fungi in commercial rice (Oryza sativa) showed significant elevation in plant growth, especially in the case of the AwOcstreb1 inoculants, which had enhanced metabolite and chlorophyll content at the seedling stage in both no-salt control and 100-mm salt-stressed plants. At the same time, AwOcstreb1-treated plants had a significantly lower level of H2O2, electrolyte leakage, and Na+/K+ ratio under saline conditions. Higher expression (1.6 folds) of the SOS1 (salt overly sensitive 1) gene was also observed in these plants under salinity stress. This strain also improved percent fertility, tillering, panicle number, and filled grain number in both no-salt control and 45-mm salt-stressed inoculated plants at the reproductive stage. Consequently, the differences in their yield was 125.16% and 203.96% (p < 0.05) in colonized plants in normal and saline conditions, respectively, compared to uninoculated controls.ConclusionsWe propose that AwOcstreb1 is a potential candidate for an eco-friendly biofertilizer formula to improve the cultivation and yield of rice or any other crop in the highly saline coastal regions of Bangladesh.

Immunolocalization of Jasmonates and Auxins in Pea Roots in Connection with Inhibition of Root Growth under Salinity Conditions.

Inhibition of root elongation is an important growth response to salinity, which is thought to be regulated by the accumulation of jasmonates and auxins in roots. Nevertheless, the mechanisms of the interaction of these hormones in the regulation of the growth response to salinity are still not clear enough. Their better understanding depends on the study of the distribution of jasmonates and auxins between root cells. This was achieved with the help of immunolocalization of auxin (indoleacetic acid) and jasmonates on the root sections of pea plants. Salinity inhibited root elongation and decreased the size of the meristem zone and the length of cells in the elongation zone. Immunofluorescence based on the use of appropriate, specific antibodies that recognize auxins and jasmonates revealed an increased abundance of both hormones in the meristem zone. The obtained data suggests the participation of either auxins or jasmonates in the inhibition of cell division, which leads to a decrease in the size of the meristem zone. The level of only auxin and not jasmonate increased in the elongation zone. However, since some literature evidence argues against inhibition of root cell division by auxins, while jasmonates have been shown to inhibit this process, we came to the conclusion that elevated jasmonate is a more likely candidate for inhibiting root meristem activity under salinity conditions. Data suggests that auxins, not jasmonates, reduce cell size in the elongation zone of salt-stressed plants, a suggestion supported by the known ability of auxins to inhibit root cell elongation.

Microbes with high–abundance attributes dominate the prokaryote communities of saline–alkali soil and construct more complex networks in the plant rhizosphere

Understanding the interactions between plants and microbes in terms of core and/or keystone taxa is of great importance for promoting salt tolerant of plants and comprehensive utilisation of saline–alkali lands. However, our knowledge about the dominant microbial categories and their response to plant growth is limited. Here, we distinguished the categories of core and keystone taxa by classifying the prokaryotic categories and conducting network analysis in saline–alkali lands. Moreover, we explored how these important taxa varied between the plant rhizosphere and bulk soils. Overall, six categories of prokaryotes were identified. Approximately one–tenth of the species with high–abundance attributes accounted for two–thirds of total prokaryotes. Moreover, network analysis showed that nearly all links among the nodes were positive; and the identified keystone taxa mainly belonged to categories with high–abundance attributes. Furthermore, in the rhizosphere, a decreasing trend in the correlations of microbial diversity indices and community compositions with the soil properties was observed compared with those in the bulk soil. However, more keystone taxa and complex modules were strongly correlated with changes in the soil properties. These results suggest that the plant rhizosphere can recruit keystone prokaryotes with high–abundance attributes by establishing a syntrophic association between the plant and keystone taxa, which subsequently construct a complex microbial network structure. Although the ecological functions of the targeted keystone taxa need to be confirmed, our findings provide a potential method for constructing a core artificial microbiome with multiple approaches, further helping to develop microbial strategies to ameliorate salt stress in plants in saline–alkali lands.

Nitric Oxide Modulates Salt Stress Tolerance in Lettuce

Crops are constantly threatened by salinity. Nitric oxide (NO) is an attenuating agent for salt stress; however, the specific roles of NO in gas exchange and lettuce production are not well established. The objective of this study was to evaluate the application of different concentrations of sodium nitroprusside (SNP) as an agent to mitigate salt stress in lettuce plants. Lettuce seedlings in pots were subjected to irrigation without and with saline water (0.2 and 3.5 dS m−1) and applications of different concentrations (0, 50, 100, 150, and 200 µM) of SNP, a NO donor. Saline stress negatively affected lettuce development with a reduction of 29.5% in leaf area, 6.3% in relative water content in the leaf, 17.2% in stem diameter, and 10.7% in dry matter mass in the control, but the application of SNP mitigated the deleterious effects of salt stress. Concentrations between 100 and 150 µM of SNP improved the photosynthetic metabolism of lettuce under salinity, with an increase of 46.7% in CO2 assimilation and 42.3% in fresh matter mass. Pearson’s correlation showed that fresh matter correlated positively with CO2 assimilation. Therefore, SNP can be used to mitigate salt stress in lettuce.

The seaweed Ascophyllum nodosum-based biostimulant enhances salt stress tolerance in rice (Oryza sativa L.) by remodeling physiological, biochemical, and metabolic responses

ABSTRACT This study explores the role of a biostimulant derived from the seaweed Ascophyllum nodosum (AN) in mitigating salt stress in rice plants. The weekly (S+W) and biweekly (S+B) biostimulant treatments exhibited enhanced shoot and root biomass, maintained ionic balance, and increased pigment content (total chlorophyll increased by 26.35% and 31%, carotenoids by 11.90% and 16.67% in S+W and S+B treatments, respectively) compared to untreated salt-stressed plants (CS). Improved gas exchange parameters and PSII efficiency were observed in S+W and S+B treatments. AN-biostimulant treatments mitigated salt-induced oxidative stress by positively regulating the antioxidant defense system. Notably, a strong negative correlation was observed between antioxidants and oxidative markers. Furthermore, AN-biostimulant treatments induced key metabolites (organic acids, sugars, amino acids, flavonoids), emphasizing the integrated role of multiple pathways in enhancing salt tolerance in rice. These findings highlight the potential of AN biostimulants as eco-friendly tools for crop enhancement in challenging environments.

Azospirillum brasilense improves rice growth under salt stress by regulating the expression of key genes involved in salt stress response, abscisic acid signaling, and nutrient transport, among others.

Major food crops, such as rice and maize, display severe yield losses (30-50%) under salt stress. Furthermore, problems associated with soil salinity are anticipated to worsen due to climate change. Therefore, it is necessary to implement sustainable agricultural strategies, such as exploiting beneficial plant-microbe associations, for increased crop yields. Plants can develop associations with beneficial microbes, including arbuscular mycorrhiza and plant growth-promoting bacteria (PGPB). PGPB improve plant growth via multiple mechanisms, including protection against biotic and abiotic stresses. Azospirillum brasilense, one of the most studied PGPB, can mitigate salt stress in different crops. However, little is known about the molecular mechanisms by which A. brasilense mitigates salt stress. This study shows that total and root plant mass is improved in A. brasilense-inoculated rice plants compared to the uninoculated plants grown under high salt concentrations (100 mM and 200 mM NaCl). We observed this growth improvement at seven- and fourteen days post-treatment (dpt). Next, we used transcriptomic approaches and identified differentially expressed genes (DEGs) in rice roots when exposed to three treatments: 1) A. brasilense, 2) salt (200 mM NaCl), and 3) A. brasilense and salt (200 mM NaCl), at seven dpt. We identified 786 DEGs in the A. brasilense-treated plants, 4061 DEGs in the salt-stressed plants, and 1387 DEGs in the salt-stressed A. brasilense-treated plants. In the A. brasilense-treated plants, we identified DEGs involved in defense, hormone, and nutrient transport, among others. In the salt-stressed plants, we identified DEGs involved in abscisic acid and jasmonic acid signaling, antioxidant enzymes, sodium and potassium transport, and calcium signaling, among others. In the salt-stressed A. brasilense-treated plants, we identified some genes involved in salt stress response and tolerance (e.g., abscisic acid and jasmonic acid signaling, antioxidant enzymes, calcium signaling), and sodium and potassium transport differentially expressed, among others. We also identified some A. brasilense-specific plant DEGs, such as nitrate transporters and defense genes. Furthermore, our results suggest genes involved in auxin and ethylene signaling are likely to play an important role during these interactions. Overall, our transcriptomic data indicate that A. brasilense improves rice growth under salt stress by regulating the expression of key genes involved in defense and stress response, abscisic acid and jasmonic acid signaling, and ion and nutrient transport, among others. Our findings will provide essential insights into salt stress mitigation in rice by A. brasilense.

Proteome-wide identification of S-sulfenylated cysteines response to salt stress in Brassica napus root

Reactive oxygen species (ROS) play a key role in a variety of biological processes, such as the perception of abiotic stress, the integration of different environmental signals, and the activation of stress response networks. Salt stress could induce an increased ROS accumulation in plants, disrupting intracellular redox homeostasis, leading to post-translational modifications (PTMs) of specific proteins, and eventually causing adaptive changes in metabolism. Here, we performed an iodoTMT-based proteomic approach to identify the sulfenylated proteins in B. napus root responsing to salt stress. Totally, 1 348 sulfenylated sites in 751 proteins were identified and these proteins were widely existed in different cell compartments and processes. Our study revealed that proteins with changed abundance and sulfenylation level in B. napus root under salt stress were mainly enriched in the biological processes of ion binding, glycolysis, ATP binding, and oxidative stress response. This study displays a landscape of sulfenylated proteins response to salt stress in B. napus root and provides some theoretical support for further understanding of the molecular mechanisms of redox regulation under salt stress in plants.

Antioxidant system was triggered to alleviate salinity stress by cytokinin oxidase/dehydrogenase gene GhCKX6b-Dt in cotton

Cytokinin oxidase/dehydrogenase (CKX) is a key regulatory enzyme for the irreversible degradation of the plant hormone cytokinin (CK), which is important in growth and development and response to abiotic stresses in cotton. In this study, 27, 28, 14 and 14 CKXs were screened by FAD structural domain and cytokinin binding structural domain in Gossypium hirsutum, Gossypium barbadense, Gossypium arboreum and Gossypium raimondii, respectively. Their phylogenetic relationships and expression patterns were analyzed, and most GhCKXs were found to be tissue-specific and responsive to various abiotic stresses such as cold, heat, salt and PEG. GhCKX6b-Dt was selected for gene silencing in evolutionary branch II for salt stress, because its expression increased after salt stress in cotton plants. An increase in PRO and MDA content and a decrease in SOD activity due to this gene were found after inducing salt stress, contributing to oxidative damage and decreased salt tolerance. In this study, CKXs were analyzed to reveal the possible role of GhCKXs against abiotic stresses in cotton, which provides a basis for further understanding of the biological functions of CK in plants such as growth and development and stress resistance.

Recent advances in PGPR-mediated resilience toward interactive effects of drought and salt stress in plants.

The present crisis at hand revolves around the need to enhance plant resilience to various environmental stresses, including abiotic and biotic stresses, to ensure sustainable agriculture and mitigate the impact of climate change on crop production. One such promising approach is the utilization of plant growth-promoting rhizobacteria (PGPR) to mediate plant resilience to these stresses. Plants are constantly exposed to various stress factors, such as drought, salinity, pathogens, and nutrient deficiencies, which can significantly reduce crop yield and quality. The PGPR are beneficial microbes that reside in the rhizosphere of plants and have been shown to positively influence plant growth and stress tolerance through various mechanisms, including nutrient solubilization, phytohormone production, and induction of systemic resistance. The review comprehensively examines the various mechanisms through which PGPR promotes plant resilience, including nutrient acquisition, hormonal regulation, and defense induction, focusing on recent research findings. The advancements made in the field of PGPR-mediated resilience through multi-omics approaches (viz., genomics, transcriptomics, proteomics, and metabolomics) to unravel the intricate interactions between PGPR and plants have been discussed including their molecular pathways involved in stress tolerance. Besides, the review also emphasizes the importance of continued research and implementation of PGPR-based strategies to address the pressing challenges facing global food security including commercialization of PGPR-based bio-formulations for sustainable agricultural.