Salicylic acid improves cowpea productivity under water restriction in the field by modulating metabolism.

Introduction: Salicylic acid has shown promise in alleviating water stress in cultivated plants. However, there is a lack of studies confirming its effectiveness in cowpea plants grown in field conditions. Therefore, this research aimed to evaluate the use of salicylic acid as a water stress mitigator in cowpea cultivars under different irrigation depths in field conditions. Methods: Four cowpea cultivars (BRS Novaera, BRS Tapaihum, BRS Pujante, and BRS Pajeú) were subjected to different treatments: control (W100: 100% replacement of crop evapotranspiration - ETc), W50 (50% of ETc), W50+SA2 (50% of ETc + 276 mg L-1 of SA), and W50+SA4 (50% of ETc + 552 mg L-1 of SA). The treatments were combined in a 4×4 factorial scheme with three replications, arranged in a randomized block design. Results: Water restriction had a negative impact on the water status, growth, gas exchange, and production of the cultivars while also leading to changes in the antioxidant metabolism and osmolyte concentration. The application of SA enhanced antioxidant activity and the synthesis of osmotic adjusters under stress conditions. The most effective concentration was 276 mg L-1 in stage R2 and 552 mg L-1 in stage V7, respectively. The BRS Pujante cultivar showed increased productivity under water restriction with SA application, while the BRS Tapaihum was the most tolerant among the cultivars studied. Discussion: In summary, our findings underscore the importance of using SA to mitigate the effects of water restriction on cowpea cultivation. These discoveries are crucial for the sustainability of cowpea production in regions susceptible to drought, which can contribute to food security. We further add that the adoption of new agricultural practices can enhance the resilience and productivity of cowpea as an essential and sustainable food source for vulnerable populations in various parts of the world.

The metabolic fingerprint of Scots pine-root and needle metabolites show different patterns in dying trees.

The loss of leaves and needles in tree crowns and tree mortality are increasing worldwide, mostly as a result of more frequent and severe drought stress. Scots pine (Pinus sylvestris L.) is a tree species that is strongly affected by these developments in many regions of Europe and Asia. So far, changes in metabolic pathways and metabolite profiles in needles and roots on the trajectory toward mortality are unknown, although they could contribute to a better understanding of the mortality mechanisms. Therefore, we linked long-term observations of canopy defoliation and tree mortality with the characterization of the primary metabolite profile in needles and fine roots of Scots pines from a forest site in the Swiss Rhone valley. Our results show that Scots pines are able to maintain metabolic homeostasis in needles over a wide range of canopy defoliation levels. However, there is a metabolic tipping point at around 80-85% needle loss. Above this threshold, many stress-related metabolites (particularly osmoprotectants, defense compounds and antioxidants) increase in the needles, whereas they decrease in the fine roots. If this defoliation tipping point is exceeded, the trees are very likely to die within a few years. The different patterns between needles and roots indicate that mainly belowground carbon starvation impairs key functions for tree survival and suggest that this is an important factor explaining the increasing mortality of Scots pines.

Comparative Analysis of the Osmoprotective Effects of Daily Disposable Contact Lens Packaging Solutions on Human Corneal Epithelial Cells.

Purpose: Contact lens (CL) wear challenges the balance of the ocular surface environment by increasing water evaporation and tear osmolarity. Maintaining ocular surface homeostasis during CL wear remains a goal of lens manufacturers and an important consideration for eye care professionals. The purpose of this study was to measure the metabolic activity and inflammatory responses of a transformed human corneal epithelial cell (THCEpiC) line under hyperosmotic conditions in the presence of CL packaging solutions. Methods: CL packaging solutions sampled from seven daily disposable silicone hydrogel CL blister packages were prepared at 25% and made hyperosmolar (400 mOsm/kg) with NaCl. THCEpiCs were incubated with each solution for 24 hr, after which cell culture supernatants were collected. THCEpiC metabolic activity was determined by an alamarBlue assay. Concentrations in cell culture supernatants of inflammatory cytokine (interleukin [IL]-6) and chemokine (IL-8), as well as monocyte chemoattractant protein-1 (MCP-1), were quantitated by specific enzyme-linked immunosorbent assays. Results: THCEpiC metabolic activity under hyperosmolar conditions decreased in the presence of somofilcon A and senofilcon A solutions (p=0.04 and 0.004, respectively), but no other solution (all p≥0.09). Concentrations of IL-6 increased in the presence of delefilcon A, somofilcon A, narafilcon A, and senofilcon A solutions (all p≤0.001), but no other solution (all p≥0.08), while those of IL-8 increased in the presence of all solutions (all p≤0.03) but kalifilcon A (p>0.99), and those of MCP-1 increased in the presence of delefilcon A, verofilcon A, somofilcon A, and stenfilcon A solutions (all p<0.0001), but no other solution (all p>0.99). Conclusion: CL packaging solutions differ in their capacity to inhibit epithelial inflammation. THCEpiC inflammatory response was less in the presence of a CL packaging solution containing osmoprotectants than in solutions lacking osmoprotectants under moderately hyperosmolar conditions in vitro. Clinical studies are warranted to further substantiate the benefit of osmoprotectants.

New trends towards glaucoma treatment: Topical osmoprotective microemulsions loaded with latanoprost.

The chronic use of hypotensive agents eventually leads to ocular surface damage and poor patient compliance during glaucoma management. Thus, new sustained drug delivery systems are needed. This work aimed to develop osmoprotective latanoprost-loaded microemulsion formulations as new potential glaucoma treatments with ocular surface protective properties. The microemulsions were characterized and latanoprost encapsulation efficacy determined. In-vitro tolerance, osmoprotective efficacy, cell internalization as well as cell-microemulsion interactions and distribution were performed. In vivo hypotensive activity was conducted in rabbits to assess intraocular pressure reduction and relative ocular bioavailability. Physicochemical characterization showed nanodroplet sizes within 20-30 nm, being in vitro tolerance within 80 and 100% viability in corneal and conjunctival cells. Besides, microemulsions exhibited higher protection under hypertonic conditions than untreated cells. Cell fluorescence lasted for 11 days after short exposure to coumarin-loaded microemulsions (5 min) showing extensive internalization in different cell compartments by electronic microscopy. In vivo studies exhibited that a single instillation of latanoprost-loaded microemulsions reduced the intraocular pressure for several days (4-6 days without polymer and 9-13 days with polymers). Relative ocular bioavailability was 4.5 and 19 times higher than the marketed formulation. These findings suggest the use of these microemulsions as potential combined strategies for extended surface protection and glaucoma treatment.

Cyanobacteria as cell factories for the photosynthetic production of sucrose.

Biofuels and other biologically manufactured sustainable goods are growing in popularity and demand. Carbohydrate feedstocks required for industrial fermentation processes have traditionally been supplied by plant biomass, but the large quantities required to produce replacement commodity products may prevent the long-term feasibility of this approach without alternative strategies to produce sugar feedstocks. Cyanobacteria are under consideration as potential candidates for sustainable production of carbohydrate feedstocks, with potentially lower land and water requirements relative to plants. Several cyanobacterial strains have been genetically engineered to export significant quantities of sugars, especially sucrose. Sucrose is not only naturally synthesized and accumulated by cyanobacteria as a compatible solute to tolerate high salt environments, but also an easily fermentable disaccharide used by many heterotrophic bacteria as a carbon source. In this review, we provide a comprehensive summary of the current knowledge of the endogenous cyanobacterial sucrose synthesis and degradation pathways. We also summarize genetic modifications that have been found to increase sucrose production and secretion. Finally, we consider the current state of synthetic microbial consortia that rely on sugar-secreting cyanobacterial strains, which are co-cultivated alongside heterotrophic microbes able to directly convert the sugars into higher-value compounds (e.g., polyhydroxybutyrates, 3-hydroxypropionic acid, or dyes) in a single-pot reaction. We summarize recent advances reported in such cyanobacteria/heterotroph co-cultivation strategies and provide a perspective on future developments that are likely required to realize their bioindustrial potential.

Bacilli Rhizobacteria as Biostimulants of Growth and Production of Sesame Cultivars under Water Deficit.

A strategy using bacilli was adopted aiming to investigate the mitigation of the effects of water deficit in sesame. An experiment was carried out in a greenhouse with 2 sesame cultivars (BRS Seda and BRS Anahí) and 4 inoculants (pant001, ESA 13, ESA 402, and ESA 441). On the 30th day of the cycle, irrigation was suspended for eight days, and the plants were subjected to physiological analysis using an infrared gas analyzer (IRGA). On the 8th day of water suspension, leaves were collected for analysis: superoxide dismutase, catalase, ascorbate peroxidase, proline, nitrogen, chlorophyll, and carotenoids. At the end of the crop cycle, data on biomass and vegetative growth characteristics were collected. Data were submitted for variance analysis and comparison of means by the Tukey and Shapiro-Wilk tests. A positive effect of inoculants was observed for all characteristics evaluated, contributing to improvements in plant physiology, induction of biochemical responses, vegetative development, and productivity. ESA 13 established better interaction with the BRS Anahí cultivar and ESA 402 with BRS Seda, with an increase of 49% and 34%, respectively, for the mass of one thousand seeds. Thus, biological indicators are identified regarding the potential of inoculants for application in sesame cultivation.

MicroRNA172b-5p/trehalose-6-phosphate synthase module stimulates trehalose synthesis and microRNA172b-3p/AP2-like module accelerates flowering in barley upon drought stress.

MicroRNAs (miRNAs) are major regulators of gene expression during plant development under normal and stress conditions. In this study, we analyzed the expression of 150 conserved miRNAs during drought stress applied to barley ready to flower. The dynamics of miRNAs expression was also observed after rewatering. Target messenger RNA (mRNAs) were experimentally identified for all but two analyzed miRNAs, and 41 of the targets were not reported before. Drought stress applied to barley induced accelerated flowering coordinated by a pair of two differently expressed miRNAs originating from a single precursor: hvu-miR172b-3p and hvu-miR172b-5p. Increased expression of miRNA172b-3p during drought leads to the downregulation of four APETALA2(AP2)-like genes by their mRNA cleavage. In parallel, the downregulation of the miRNA172b-5p level results in an increased level of a newly identified target, trehalose-6-phosphate synthase, a key enzyme in the trehalose biosynthesis pathway. Therefore, drought-treated plants have higher trehalose content, a known osmoprotectant, whose level is rapidly dropping after watering. In addition, trehalose-6-phosphate, an intermediate of the trehalose synthesis pathway, is known to induce flowering. The hvu-miRNA172b-5p/trehalose-6-phosphate synthase and hvu-miRNA172b-3p/AP2-like create a module leading to osmoprotection and accelerated flowering induction during drought.

A novel osmoprotective liposomal formulation from synthetic phospholipids to reduce in vitro hyperosmolar stress in dry eye treatments.

Dry eye disease (DED) is a worldwide, multifactorial disease mainly caused by a deficit in tear production or increased tear evaporation with an increase in tear osmolarity and inflammation. This causes discomfort and there is a therapeutic need to restore the homeostasis of the ocular surface. The aim of the present work was to develop a biodegradable and biocompatible liposomal formulation from the synthetic phospholipids 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC) and 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC) that is able to reduce the effects of hypertonic stress by helping to restore the lipid layer of the tear film. Liposomes were made using the lipid film hydration method with synthetic phospholipids (10 mg/mL) with and without 0.2% HPMC. They were characterised in terms of size, osmolarity, pH, surface tension, and viscosity. Additionally, the in vitro toxicity of the formulation at 1 and 4 h in human corneal epithelial cells (hTERT-HCECs) and human conjunctival cells (IM-HConEpiC) was determined. Furthermore, osmoprotective activity was tested in a corneal model of hyperosmolar stress. In vivo acute tolerance testing was also carried out in albino New Zealand rabbits by topical application of the ophthalmic formulations every 30 min for 6 h. All the assayed formulations showed suitable physicochemical characteristics for ocular surface administration. The liposomal formulations were well-tolerated in cell cultures and showed osmoprotective activity in a hyperosmolar model. No alterations or discomfort were reported when they were topically administered in rabbits. According to the results, the osmoprotective liposomal formulations developed in this work are promising candidates for the treatment of DED.

Modulation of osmoprotection and antioxidant defense by exogenously applied acetate enhances cadmium stress tolerance in lentil seedlings.

To examine the potential role of acetate in conferring cadmium (Cd) stress tolerance in lentil (Lens culinaris), several phenotypical and physio-biochemical properties have been examined in Cd-stressed lentil seedlings following acetate applications. Acetate treatment inhibited the translocation of Cd from roots to shoots, which resulted in a minimal reduction in photosynthetic pigment contents. Additionally, acetate-treated lentil showed higher shoot (1.1 and 11.72%) and root (4.98 and 30.64%) dry weights compared with acetate-non-treated plants under low-Cd and high-Cd concentrations, respectively. Concurrently, acetate treatments increase osmoprotection under low-Cd stress through proline accumulation (24.69%), as well as enhancement of antioxidant defense by increasing ascorbic acid content (239.13%) and catalase activity (148.51%) under high-Cd stress. Acetate-induced antioxidant defense resulted in a significant diminution in hydrogen peroxide, malondialdehyde and electrolyte leakage in Cd-stressed lentil seedlings. Our results indicated that acetate application mitigated oxidative stress-induced damage by modulating antioxidant defense and osmoprotection, and reducing root-to-shoot Cd transport. These findings indicate an important contribution of acetate in mitigating the Cd toxicity during growth and development of lentil seedlings, and suggest that the exogenous applications of acetate could be an economical and new avenue for controlling heavy metal-caused damage in lentil, and potentially in many other crops.

Development of an osmoprotective microemulsion as a therapeutic platform for ocular surface protection.

Self-emulsified osmoprotective ophthalmic microemulsions (O/A) were prepared by combining betaine/leucine, clusterin/oleanolic acid, and hyaluronic acid or Dextran. The microemulsions contained an internal oily phase (1.2%), an external aqueous phase (96.3%), cosolvents (1%), and surfactants (1.5%). Physicochemical characterization and in vivo and in vitro tolerance were analyzed. The formulations' osmoprotective in vitro activity was assayed in a hyperosmolar model in human corneal cells. Average internal phase sizes were 16-26 nm for the microemulsions including Dextran. Addition of hyaluronic acid increased the size range (25-39 nm). Addition of osmoprotectants did not change nanodroplet size. The formulations were isotonic (280-290 mOsm/L) with neutral pH (≈7) and zeta potential (-10 to 0 mV), low surface tension (≈35-40mN·m-1), and low viscosity (≈1 mPa·s), except for the microemulsions containing hyaluronic acid (≈4-5 mPa·s). SEM and cryo-TEM showed that all formulations exhibited sphere-shaped morphology with good cell tolerance (≈100%) and were stable at 8 °C for 9 months. Osmoprotective formulations were well tolerated in vitro and in vivo, protecting cells from hypertonic stress. We therefore developed stable microemulsions compatible with the ocular surface that could constitute a novel tool for treatment of ophthalmic diseases.

Glycine Betaine and ß-Aminobutyric Acid Mitigate the Detrimental Effects of Heat Stress on Chinese Cabbage (Brassica rapa L. ssp. pekinensis) Seedlings with Improved Photosynthetic Performance and Antioxidant System.

Heat stress is one of the major abiotic factors that limit the growth, development, and productivity of plants. Both glycine betaine (GB) and ß-aminobutyric acid (BABA) have received considerable attention due to their roles in stimulating tolerance to diverse abiotic stresses. In order to understand how GB and BABA biostimulants alleviate heat stress in a cool-weather Chinese cabbage (Brassica rapa L. ssp. pekinensis) plant, we investigated the GB- and BABA-primed heat-stressed plants in terms of their morpho-physiological and biochemical traits. Priming with GB (15 mM) and BABA (0.2 mM) was conducted at the third leaf stage by applying foliar sprays daily for 5 days before 5 days of heat stress (45 °C in 16 h light/35 °C in 8 h dark) on Chinese cabbage seedlings. The results indicate that GB and BABA significantly increased chlorophyll content, and the parameters of both gas exchange and chlorophyll fluorescence, of Chinese cabbage under heat stress. Compared with the unprimed heat-stressed control, the dry weights of GB- and BABA-primed plants were significantly increased by 36.36% and 45.45%, respectively. GB and BABA priming also greatly mitigated membrane damage, as indicated by the reduction in malondialdehyde (MDA) and electrolyte leakage through the elevation of proline content, and increased activity levels of superoxide dismutase (SOD), peroxidase (POD), catalase (CAT), and ascorbate peroxidase (APX). Taken together, GB and BABA have great potential to enhance the thermotolerance of Chinese cabbage through higher photosynthesis performance, osmoprotection, and antioxidant enzyme activity.

Efficacy of topical cyclosporine 0.05% and osmoprotective lubricating eye drops in treating dry eye disease and inflammation.

PURPOSE: To evaluate the effect of topical cyclosporine 0.05% and osmoprotective lubricating eye drops on patients with dry eye disease (DED) with inflammation as measured by raised tear matrix metalloproteinases (MMP-9). METHODS: This prospective study included 106 eyes of 53 patients diagnosed with DED based on any of the following DED criteria (Ocular Surface Disease Index [OSDI] score >12, tear film breakup time [TBUT] <10 s, Schirmer's I test result <10 mm/5 min, ocular surface staining). Ocular surface inflammation was assessed by assessing MMP-9 positivity from tears of the patients in the study (Inflammadry kit Quidel corporation). Patients were prescribed osmoprotective lubricating eye drops (Osmodrops, Cipla Ltd) four times a day and cyclosporine A 0.05% eye drops (Imudrops, Cipla Ltd) twice a day for 6 months. Efficacy of the formulations was evaluated by OSDI scores, Schirmer's test, TBUT change, reduction in ocular surface staining, and reduction in MMP-9 levels after 6 months of usage. Check P value and add from results. RESULTS: After 6 months of topical therapy, improvement was observed in OSDI scores (mean pretreatment: 25.7 ± 12.8, and mean posttreatment: 15.2 ± 8.4), P < 0.001. There was also reduction number of patients who were MMP-9 positive. Out of 75 eyes that tested MMP-9 positive, 70.66% showed reduction in MMP-9 levels P < 0.0001). Ocular surface staining also improved. CONCLUSION: Topical osmoprotective lubricating eye drops and cyclosporine A 0.05% reduce inflammation in cases of DED, which correlates with improvement in OSDI scores, ocular surface staining, and reduction in inflammation as measured by levels of tear MMP-9.

Optimization of a Cryopreservation Method for the Endangered Korean Species Pogostemon yatabeanus Using a Systematic Approach: The Key Role of Ammonium and Growth Regulators.

Cryopreservation provides a secure long-term conservation option for rare and endangered plant species with non-orthodox or limitedly available seeds. Wide application of cryopreservation to biobank wild flora is hampered by the need to re-optimize nearly all protocol steps for every new species. We applied a systematic approach to simplify optimization of a multi-stage droplet-vitrification method for the endangered wetland Korean species, Pogostemon yatabeanus. This approach consisted of a standard procedure pre-selected based on material type and size, which was complemented with 11 additional treatments to reveal the most impactful conditions. Effect of ammonium nitrate at various protocol steps was also tested. The highest shoot tip survival (92%) and plant regeneration (90%) after cryopreservation were achieved using preculture with 10% sucrose followed by 40 min osmoprotection and 60 min treatment with vitrification solution A3-80% (33.3% glycerol + 13.3% dimethyl sulfoxide + 13.3% ethylene glycol + 20.1% sucrose) on ice. A three-step regrowth procedure starting with ammonium-free medium with 1 mg/L GA3 and 1 mg/L BA followed by ammonium-containing medium with and without growth regulators was essential for the development of healthy plants from cryopreserved shoot tips. This approach enables fast optimization of the cryopreservation procedure for new osmotic stress-sensitive plant species.

Combined hyperosmolarity and inflammatory conditions in stressed human corneal epithelial cells and macrophages to evaluate osmoprotective agents as potential DED treatments.

PURPOSE: To develop an easy-to-perform combined model in human corneal epithelial cells (HCECs) and Balb/c mice macrophages J774.A1 (MP) for preliminary screening of potential ophthalmic therapeutic substances. METHODS: HCECs were exposed to different osmolarities (350-500 mOsm/L) and MTT assay was employed for cell survival and flow cytometry to assess apoptosis-necrosis and relative cell size (RCS) distribution. Effectiveness of Betaine, L-Carnitine, Taurine at different concentrations (ranging from 20 mM to 200 mM) was studied. Also, mucoadhesive polymers such as Hyaluronic acid (HA) and Hydroxypropylmethylcellulose (HPMC) (0.4 and 0.8%) were evaluated. Cells were pre-incubated with the compounds (8h) and then exposed to hyperosmotic stress (470 mOsm/L) for 16h. Moreover, anti-inflammatory activity was performed in LPS-stimulated MP. RESULTS: Exposure to hyperosmotic solutions between 450 and 500 mOsm/L promoted the highest cell death after 16h exposures (p < 0.0001) with a drop in viability to 34.96% ± 11.77 for 470 mOsm/L. Pre-incubation with Betaine at 150 mM and 200 mM provided the highest cell survival against hyperosmolarity (66.01% ± 3.65 and 65.90% ± 0.78 respectively) while HA 0.4% was the most effective polymer in preventing cell death (42.2% ± 3.60). Flow cytometry showed that Betaine and Taurine at concentrations between 150-200 mM and 20-80 mM respectively presented the highest anti-apoptotic activity. Also, HA and HPMC polymers reduced apoptotic-induced cell death. All osmoprotectants modified RCS, and polymers increased their value over 100%. L-Carnitine 50 mM, Taurine 40 mM and HA 0.4% presented the highest TNF-α inhibition activity (60%) albeit all of them showed anti-inflammatory inhibition percentages higher than 20% CONCLUSIONS: HCECs hyperosmolar model combined with inflammatory conditions in macrophages allows the screening of osmoprotectants by simulating chronic hyperosmolarity (16h) and inflammation (24h).

Insight into the thiourea-induced drought tolerance in two chickpea varieties: Regulation of osmoprotection, reactive oxygen species metabolism and glyoxalase system.

The sulfhydryl bioregulator thiourea (TU) is effective in ameliorating the negative impact of different abiotic stresses in plants. To explore the significant performance of TU (5 mM TU, as foliar spray) in conferring mild (25% depletion of water from field capacity, FC), moderate (50% depletion from FC) and severe (75% depletion from FC) drought stress (applied at 25 days after sowing), physiological and biochemical responses of two chickpea (Cicer arietinum L.) cultivars (cv. BARI Chola-7 and BARI Chola-9) were investigated in the current study. Shoot fresh weight, dry weight, chlorophyll content and leaf relative water content reduced noticeably in mild, moderate and severe drought stresses over control. A sharp increase of H2O2 accumulation, thiobarbituric acid reactive substances and proline content were noticed at any level of drought stress which further declined in TU-treated drought-stressed plants. Thiourea-foliar application also increased ascorbate and glutathione contents and upregulated antioxidant enzyme activities, compared to drought-stressed plants alone. Thiourea-induced increased glyoxalase I and glyoxalase II activities are the indications of upregulated methylglyoxal detoxification system. Enhancement of antioxidant defense and glyoxalase system, osmoregulation and protection of photosynthetic pigments by TU improved growth, imparted oxidative stress tolerance, ameliorated ROS toxicity and improved physiology of chickpea plants under drought stress.

Commercially Available Eye Drops Containing Trehalose Protect Against Dry Conditions via Autophagy Induction.

Purpose: Evaluation of marketed eye drops with or without trehalose, a nonreducing natural osmoprotector disaccharide, in autophagy modulation and its role in cell survival during desiccation. Methods: Eye drops containing either sodium hyaluronate (SH) (Hyabak®, Thea, France) or a combination of SH with trehalose (Thealose Duo®, Thea, France) were compared with control conditions to evaluate the ability to modulate autophagy in human epithelial cells in vitro. Autophagy was monitored using LC3, a marker of the autophagic machinery, by fluorescence microscopy and immunoblot analysis. Control and autophagy-deficient cells treated with eye drops were exposed to desiccation to mimic dry eyes and cell survival was evaluated by thiazolyl blue tetrazolium bromide (MTT) assay. Trehalose, a known autophagy inducer was used as a positive control. Results: Artificial tears containing SH with and without trehalose induce a complete autophagic flux, as indicated by an increase in the number of autophagosomes and autolysosomes, and the accumulation of the lipidated form of LC3 associated with complete autophagy. In addition, there was a synergistic effect of SH for autophagy induction when combined with trehalose, compared with each of the components alone. Survival of cells treated with both eye drops and exposed to desiccation was decreased in autophagy-deficient cells, demonstrating the essential role of autophagy on eye drop protection. Conclusions: Autophagic flux is induced by SH-containing eye drops, and this phenomenon is enhanced in combination with trehalose. We also demonstrated that autophagy induction is involved in the osmoprotective effects of both trehalose and SH-containing eye drops, to maintain epithelial cell homeostasis in dry conditions.

Recent progress in understanding salinity tolerance in plants: Story of Na+/K+ balance and beyond.

High salt concentrations in the growing medium can severely affect the growth and development of plants. It is imperative to understand the different components of salt-tolerant network in plants in order to produce the salt-tolerant cultivars. High-affinity potassium transporter- and myelocytomatosis proteins have been shown to play a critical role for salinity tolerance through exclusion of sodium (Na+) ions from sensitive shoot tissues in plants. Numerous genes, that limit the uptake of salts from soil and their transport throughout the plant body, adjust the ionic and osmotic balance of cells in roots and shoots. In the present review, we have tried to provide a comprehensive report of major research advances on different mechanisms regulating plant tolerance to salinity stress at proteomics, metabolomics, genomics and transcriptomics levels. Along with the role of ionic homeostasis, a major focus was given on other salinity tolerance mechanisms in plants including osmoregulation and osmo-protection, cell wall remodeling and integrity, and plant antioxidative defense. Major proteins and genes expressed under salt-stressed conditions and their role in enhancing salinity tolerance in plants are discussed as well. Moreover, this manuscript identifies and highlights the key questions on plant salinity tolerance that remain to be discussed in the future.

In vivo light-sheet microscopy resolves localisation patterns of FSD1, a superoxide dismutase with function in root development and osmoprotection.

Superoxide dismutases (SODs) are enzymes detoxifying superoxide to hydrogen peroxide while temporal developmental expression and subcellular localisation are linked to their functions. Therefore, we aimed here to reveal in vivo developmental expression, subcellular, tissue- and organ-specific localisation of iron superoxide dismutase 1 (FSD1) in Arabidopsis using light-sheet and Airyscan confocal microscopy. FSD1-GFP temporarily accumulated at the site of endosperm rupture during seed germination. In emerged roots, it showed the highest abundance in cells of the lateral root cap, columella, and endodermis/cortex initials. The largest subcellular pool of FSD1-GFP was localised in the plastid stroma, while it was also located in the nuclei and cytosol. The majority of the nuclear FSD1-GFP is immobile as revealed by fluorescence recovery after photobleaching. We found that fsd1 knockout mutants exhibit reduced lateral root number and this phenotype was reverted by genetic complementation. Mutant analysis also revealed a requirement for FSD1 in seed germination during salt stress. Salt stress tolerance was coupled with the accumulation of FSD1-GFP in Hechtian strands and superoxide removal. It is likely that the plastidic pool is required for acquiring oxidative stress tolerance in Arabidopsis. This study suggests new developmental and osmoprotective functions of SODs in plants.

Exogenous kinetin and putrescine synergistically mitigate salt stress in Luffa acutangula by modulating physiology and antioxidant defense.

Salinity is one of the most vicious environmental constraints that hamper agricultural production. Experiments were done to explore the significant role of sole and synergistic supplementation of kinetin (100 µM KN) and putrescine (100 µM PUT) on Luffa acutangula in NaCl (100 mM) treatment. The harmful effects of salinity on growth were manifested by decreased seedling length, biomass, and pigment contents. We studied the effect of KN, and PUT in preventing salt (NaCl) induced physiological disorders and oxidative damages in 20-day-old Luffa acutangula seedlings. The individual application of KN and PUT increased growth and biochemical parameters, whereas combined KN + PUT treatment showed significant enhancement in growth, photosynthetic pigment content, and osmolyte accumulation in salt-affected plants. Application of KN and PUT also prevented hydrogen peroxide and superoxide production as confirmed by inhibition in electrolyte leakage and lipid peroxidation. Kinetin and PUT application upregulated the antioxidant defense system by enhancing antioxidant enzymes and non-enzymatic contents. Luffa seedlings treated with NaCl + KN + PUT showed 79, 26, 74, and 73% rise in superoxide dismutase, catalase, ascorbate peroxidase, and glutathione reductase enzymes, respectively, in comparison to NaCl-stressed Luffa acutangula. Findings revealed that synergistic utilization of KN and PUT modulate growth and biochemical processes in seedlings efficaciously in comparison to the individual application under salt stress, and it may be due to a regulatory crosstalk mechanism.

Potential osmoprotective roles of branchial heat shock proteins towards Na+, K+-ATPase in milkfish (Chanos chanos) exposed to hypotonic stress.

In euryhaline teleosts, osmoregulatory mechanisms vary with osmotic stresses, and heat shock proteins (HSPs) play a central role in maintaining cellular homeostasis. The present study aimed to investigate the expression and potential roles of HSP70 and HSP90 in the gills of seawater (SW)- and freshwater (FW)-acclimated milkfish (Chanos chanos). Four HSP genes, including Cchsc70 (heat shock cognate 70), Cchsp70, Cchsp90α, and Cchsp90ß, were analyzed in milkfish gills. Among these genes, only the mRNA abundance of branchial Cchsp90α was significantly lower in the FW-acclimated than in the SW-acclimated milkfish. Immunoblotting showed no significant difference in the relative protein abundance of branchial HSP70 and HSP90 between the two groups. The time-course experiments (from SW to FW) showed that the protein abundance of HSP70 and HSP90 at the 3 h and 6 h post-transfer and then declined gradually. To further illustrate the potential osmoregulatory roles of HSP70 and HSP90, their interaction with Na+, K+-ATPase (NKA, the primary driving force for osmoregulation) was analyzed using co-immunoprecipitation. The results showed the interaction between HSP70, HSP90 and NKA after acclimation to SW or FW increased within 3 h; and then returned to normal levels within 7 days. To our knowledge, the present study was the first to demonstrate that the interaction between HSP70, HSP90 and NKA changes with hypotonic stress in euryhaline teleosts. Before the transfer, no interaction was detected. When transferred to FW from SW, the interaction of HSP70 and HSP90 with NKA were detected. The results suggested that HSP70 and HSP90 participated in the acute responses of osmoregulatory mechanisms to protect branchial NKA from hypotonic stress in milkfish.