Salinity Stress Research Articles

Severe hydronephrosis complicated with primary aldosteronism: a case report and review of the literature

BackgroundPrimary aldosteronism is characterized by high plasma aldosterone and low renin. The plasma aldosterone-to-renin ratio is recommended for screening. Severe hydronephrosis leads to renal parenchymal ischemia, resulting in increased renin secretion. Since nonsuppression of renin may cause a negative result in the aldosterone-to-renin ratio test, severe hydronephrosis and primary aldosteronism occurring simultaneously in a patient are challenging to diagnose.Case presentationA 54-year-old Chinese man of Han ethnicity was diagnosed with hypertension and severe hypokalemia (minimum 1.57 mmol/L) 13 years prior, and was also diagnosed with severe hydronephrosis due to congenital ureteral stenosis on the left side. His clinical features suggested primary aldosteronism, but the aldosterone-to-renin ratio result of the patient was negative every time he underwent the primary aldosteronism screening test. No further treatment for primary aldosteronism was performed, which led the patient to suffer from severe hypokalemia, such that he was taking 12–15 g/day potassium chloride orally to keep his blood potassium between 3.0 and 3.5 mmol/L (reference value, 3.5–5.5 mmol/L) for 13 years, and the patient needed to be hospitalized in the intensive care unit for rescue several times. At admission, although the aldosterone-to-renin ratio result of the patient was negative, we still did the saline stress test and captopril inhibition test, and the results showed that the plasma aldosterone level was not lower after the test than before the test. Adrenal enhanced computed tomography suggested an adenoma in the left adrenal gland, and the results of adrenal vein sampling suggested that the left side was the dominant side. Therefore, laparoscopic total resection of the left adrenal gland was performed, and 2 weeks later, the patient developed short-term renal function impairment and hyperkalemia, but his renal function and blood potassium returned to normal after treatment that included fluid rehydration. The patient’s biochemical test results and clinical symptoms were completely normal after 1 year.ConclusionWe suggest that for patients with a high suspicion of primary aldosteronism in the clinic, comprehensive analysis must be performed in combination with clinical characteristic assessments, such as severe hydronephrosis, if renin is within the normal range or if the aldosterone-to-renin ratio result is negative at screening and diagnostic tests, and adrenal vein sampling should be performed if necessary. It can help avoid misdiagnoses and contribute to the treatment of patients with severe hydronephrosis and primary aldosteronism.

Copper mitigates salinity stress by regulating water status, photosynthetic pigments and ion homeostasis and increases the yield of Eggplant (Solanum melongena)

Eggplant (Solanum melongena) is moderately sensitive to salinity. Seed priming and exogenous supplementation are technique that enhances germination, growth, and crop yield by overcoming salt stress. Therefore, this study was designed to understand the role of seed priming and copper (Cu) supplementation in modulating salt tolerance in eggplant. When exposed to salt stress, eggplant seedlings showed significantly higher Na+ content, an increased Na/K ratio, prolonged mean germination time, higher relative water loss, more days to flower bud initiation and first flowering, along with decreased germination rate, growth factors, water content, photosynthetic pigments, ionic contents (K+, Ca2+, Mg2+), and yield. The results demonstrated that the germination rate, final germination percentage, germination index, germination energy, and seed vigor index significantly improved, while the mean germination time decreased in Cu-primed seeds. The results also revealed that Cu supplementations increased seedling traits, leaf water content, photosynthetic pigment contents, ionic contents (K+, Ca2+, and Mg2+), and yield while decreasing the contents of Na+, and Na/K ratio, mean germination time, relative water loss, days to flower bud initiation, and days to 1st flowering under salt stress. Germination of seeds, seedlings growth traits, plant water status, plant pigments, yield, and ionic contents with the NaCl and Cu treatments were found to substantially interact with each other according to both hierarchical clustering and PCA. Overall, Cu seed priming and exogenous supplementation emerged as a promising strategy to enhance salt tolerance and promote germination, growth, and yield by regulating water status, photosynthetic pigments, and ion homeostasis in eggplant seedlings under NaCl stress. These findings provide valuable insights into the mechanisms of Cu-mediated stress alleviation in eggplant, with implications for sustainable crop production in saline environments.

Biostimulant Effects of Glycine Betaine in Strawberry Exposed to Salinity Stress

Biostimulant Effects of Glycine Betaine in Strawberry Exposed to Salinity Stress

A Novel MsEOBI-MsPAL1 Module Enhances Salinity Stress Tolerance, Floral Scent Emission and Seed Yield in Alfalfa.

Alfalfa (Medicago sativa L.) is an important and widely cultivated forage legume, yet its yield is constrained by salinity stress. In this study, we characterized an R2R3-MYB transcription factor MsEOBI in alfalfa. Its salt tolerance function and regulatory pathways were investigated. The nuclear-localized MsEOBI functions as a transcriptional activator, enhancing salinity tolerance by promoting the biosynthesis of flavonoids and lignin, as well as facilitating the scavenging of reactive oxygen species (ROS). Additionally, MsEOBI promotes pollinator attraction and increases seed yield by activating the biosynthesis of volatile phenylpropanoids. Yeast one-hybrid (Y1H), dual-luciferase reporter and chromatin immunoprecipitation coupled with quantitative PCR (ChIP-qPCR) assays demonstrated that MsEOBI directly binds to the promoter regions of MsPAL1, a key gene in the phenylpropanoid pathway, thereby activating its expression. Overexpression of MsPAL1 enhances salinity tolerance in alfalfa. These findings elucidate the role of the MsEOBI-MsPAL1 regulatory module and provide valuable genetic resources for the future breeding of salt-tolerant alfalfa varieties.

Tetraspanin 5 orchestrates resilience to salt stress through the regulation of ion and reactive oxygen species homeostasis in rice.

Tetraspanins (TETs) are integral membrane proteins, characterized by four transmembrane domains and a unique signature motif in their large extracellular loop. They form dynamic supramolecular complexes called tetraspanin-enriched microdomains (TEMs), through interactions with partner proteins. In plants, TETs are involved in development, reproduction and immune responses, but their role in defining abiotic stress responses is largely underexplored. We focused on OsTET5, which is differentially expressed under various abiotic stresses and localizes to both plasma membrane and endoplasmic reticulum. Using overexpression and underexpression transgenic lines we demonstrate that OsTET5 contributes to salinity and drought stress tolerance in rice. OsTET5 can interact with itself in yeast, suggesting homomer formation. Immunoblotting of native PAGE of microsomal fraction enriched from OsTET5-Myc transgenic rice lines revealed multimeric complexes containing OsTET5, suggesting the potential formation of TEM complexes. Transcriptome analysis, coupled with quantitative PCR-based validation, of OsTET5-altered transgenic lines unveiled the differential expression patterns of several stress-responsive genes, as well as those coding for transporters under salt stress. Notably, OsTET5 plays a crucial role in maintaining the ionic equilibrium during salinity stress, particularly by preserving an elevated potassium-to-sodium (K+/Na+) ratio. OsTET5 also regulates reactive oxygen species homeostasis, primarily by modulating the gene expression and activities of antioxidant pathway enzymes and proline accumulation. Our comprehensive investigation underscores the multifaceted role of OsTET5 in rice, accentuating its significance in developmental processes and abiotic stress tolerance. These findings open new avenues for potential strategies aimed at enhancing stress resilience and making valuable contributions to global food security.

Plant growth regulators affecting the physiological and yield responses of field barley genotypes to the drought and salinity stresses

Plant growth regulators affecting the physiological and yield responses of field barley genotypes to the drought and salinity stresses

Phlorotannins contribute to the ameliorative bioactivities of Ecklonia maxima-derived bioproduct in salt-stressed Solanumlycopersicum

Seaweed-derived bioproducts are increasingly being deployed as an environmentally friendly and sustainable approach to crop management under stressful growth conditions including salinity. The bioactivities of seaweed-derived extracts are linked to the presence of diverse groups of bioactive compounds. In the present study, the phlorotannins present in the seaweed Ecklonia maxima and Kelpak®, an E. maxima-derived bioproduct, were quantified and identified. Three phlorotannins were identified in E. maxima, namely eckol, 2-phloroeckol, and dibenzodioxin-fucodiphloroethol. Eckol (589.11 – 822.54 μg l−1) and dibenzodioxin-fucodiphloroethol (85 – 895 μg l−1) were present in Kelpak®. Phlorotannin bioactivity was investigated in tomato seedlings grown under NaCl-induced salinity stress. The seedlings treated with either individual phlorotannins (i.e., eckol or a fraction containing 2-phloroeckol and dibenzodioxin-fucodiphloroethol) or Kelpak® resulted in a reprogramming of biomass allocation as indicated by an increased root-to-shoot ratio. Phlorotannin and Kelpak® treatments induced the accumulation of antioxidants with an attendant augmentation of the antioxidant capacities and inhibition of membrane damage in the NaCl-stressed seedlings. Kelpak® treatment induced an increase in abscisic acid (ABA) accumulation and phlorotannin treatments lowered the ABA content of the stressed seedlings. These results demonstrated that phlorotannins contributed to the ameliorative actions of Kelpak®. The more potent effects of Kelpak®, in comparison to phlorotannins, in improving dry matter accumulation, ABA content, antioxidative properties, and inhibiting tissue injury of the salt-stressed tomato seedlings may be attributed to the presence of other bioactive components in the Kelpak® product.

Role played by arbuscular mycorrhizal fungi in amelioration of salinity stress: a review

Role played by arbuscular mycorrhizal fungi in amelioration of salinity stress: a review

Water and nutrient availability modulate the salinity stress response in Olea europaea cv. Arbequina

Salinity stress represents a key factor for global agriculture. Plants can respond to salinity stress by adapting their physiology in different ways with the aim of limiting reductions in growth and development. Importantly, moisture retention capacity, permeability and nutrient availability of substrates represent critical variables for plants as they may further influence the effect of osmotic stress. Here, a multidisciplinary approach was applied to evaluate the role of two different substrates, peat and perlite, on 2-year-old potted cuttings of Olea europaea (cultivar Arbequina) under different salinity stress conditions (0, 100 and 200 mM NaCl). Biometric and physiological data indicate that plants potted in perlite (AP) generally present lower growth and photosynthetic rates when compared with peat (AS) in combination with salinity stress. Ion measurements indicate a rise in Na+ accumulation with increasing stress severity, which alters the ion ratio in both substrates. In addition, differences occurred in polyphenol contents, with a general increase in quinic acid and rutin contents in AS and AP samples, respectively. Metabolomic and biometric data were also coupled with metabarcoding analysis, which indicates that the moderate salinity treatment (100 mM NaCl, T100) reshaped the endophytic community of plants grown on both substrates. Taken together, the data suggest that the strategy used by a glycophytic species such as the olive tree to cope with salinity stress seems to be highly related to availability of water and nutrients. The lack of both may be simulated by perlite, enhancing the effect of salinity stress response in woody plants. Lastly, applying the beneficial endophytic bacterial taxa identified here could represent a step forward in increasing plant defence and nutrient uptake and reducing inputs for modern and more sustainable agriculture.

New insights into biofouling worsening induced by salinity stress in membrane bioreactor: Response of quorum sensing system and its regulation role

Severe worsening of biofouling under salinity stress remains one of the biggest hinderances to membrane bioreactor (MBR) treating saline wastewaters and other membrane technologies applied in saline conditions e.g. seawater desalination. The underlying influential mechanism of salinity stress on biofouling was firstly investigated from the perspective of quorum sensing (QS); Response of QS to salinity stress and its role in regulating biofouling behavior were clarified. Results showed that high salinity stress (over 20 g/L of NaCl) greatly stimulated QS activity, acyl-homoserine lactones (AHLs) were increased by over 200 % and 300 % in mixed liquor and cake layer, respectively; C4-OXO-HSL, C8-OXO-HSL, C10-OXO-HSL and C12-OXO-HSL became the dominant AHLs and showed strong correlations (R2＞0.95) with changes of fouling tendency and extracellular polymeric substances (EPS) characteristics. Metagenomic sequencing further revealed that balance between QS and quorum quenching (QQ) was broken when salinity was over 20 g/L; QS related bacteria and genes were significantly enriched, meanwhile QQ related bacteria and genes were radically suppressed. QS enhancing (by exogenous AHLs) and suppressing experiments (by vanillin) collectively verified the critical regulation role that QS played in biofouling worsening under high salinity stress (mainly via altering EPS characteristics); More importantly, it was demonstrated that suppressing the highly activated QS under high salinity stress was a feasible way to curb the worsening of biofouling. Present study provided new insights into biofouling worsening induced by high salinity stress in MBR; Also, the findings could help to understand biofouling phenomenon in other membrane processes facing salinity stress.

Integrated transcriptomics, metabolomics and physiological analyses reveal differential response mechanisms of wheat to cadmium and/or salinity stress.

Many soils face dual challenges of cadmium (Cd) contamination and salinization. However, the response of crops, especially wheat, to combined Cd and salinity stress is not understood. Here, wheat was grown in a hydroponic model for 14 days under single and combined Cd and NaCl stresses. Growth parameters, tissue Cd2+ and Na+ contents, and leaf chlorophyll (Chl), O2•-, and MDA levels were determined. Comparative transcriptomic and metabolomic analyses of the leaves were performed. The results showed that combined stress had a greater inhibitory effect on Chl contents and generated more O2•- and MDA, resulting in more severe wheat growth retardation than those under Cd or NaCl stress. Stress-induced decrease in Chl levels may be attributed to the inhibition of Chl biosynthesis, activation of Chl degradation, or a decline in glutamate content. Cd addition weakened the promotional effect of NaCl on SOS1 gene expression, thereby increasing the Na+ content. Contrastingly, NaCl supplementation downregulated the Nramp and ZIP gene expressions related to Cd uptake and transport, thereby impeding Cd2+ accumulation. All stresses enhanced tryptophan content via promoting tryptophan biosynthesis. Meanwhile, Cd and NaCl stresses activated phenylpropanoid biosynthesis and purine metabolism, respectively, thereby increasing the levels of caffeic acid, fumaric acid, and uric acid. Activating the TCA cycle was important in the wheat's response to combined stress. Additionally, NaCl and combined stresses affected starch and sucrose metabolism, resulting in sucrose and trehalose accumulation. Our findings provide a comprehensive understanding of the response of wheat to the combined Cd and salinity stress.

Exploring genetic variation and genetic components under salinity stress among Basmati and Non-Basmati rice (Oryza sativa L.) cultivars

Rice (Oryza sativa L.) is an essential cereal crop which feeds more than half of the world’s population. Rice is cultivated on one-tenth of the world's arable land (approximately 150 million hectares (ha)). Its production is critically affected by salinity stress, which harms photosynthesis and growth, causing biomass loss and partial sterility. The extent of salinization of cultivable soil is increasing by 10% annually. It is predicted that more than 50% of the world's land will be damaged by salinization by 2050. In Pakistan, approximately 6.30 Mha of land is severely affected by salt stress. To cope with this problem, this study was conducted to identify saline-tolerant rice cultivars, 14 rice cultivars (PK1121 aromatic, Nonabokra, Kalomonok, PK10683, PK8892 Tol-19, Shaheen Tol-19, Chenab Tol-19, Punjab Basmati, Super Basmati 2019, Basmati 2000, Basmati 370, Basmati 385, Super Basmati, and Basmati 515 Tol-19) were grown in a 5.5 electrical conductivity (EC) salinity block to investigate their tolerance to salinity stress. Seven rice cultivars (Nonabokra, Basmati 2000, Kalomonok, Basmati 370, Basmati 385, Super Basmati, and Basmati 515 Tol-19) exhibited tolerance to salinity. Basmati 370 was tolerant to a high salinity level of 5.5 EC and showed high yield than other cultivars, however, Nonabokra outperformed other cultivars in terms of all yield attributes investigated in this study. These results were also verified via molecular screening of these genotypes by using already reported DNA markers. Polymorphic SSR marker (RM7075) associated with the SaltTOl QTL to evaluate the tolerance of rice varieties to salinity. This study showed that Nonabokra, Basmati 2000, Kalomonok, Basmati 370, Basmati 385, Super Basmati, and Basmati 515 Tol-19 performed better against salt stress and may be used as salinity-tolerant lines for future rice breeding programs.

Fulvic and Salicylic Acids Improve Morpho-Physio-Biochemical Attributes, Yield and Fruit Quality of Two Mango Cultivars Exposed to Dual Salinity and Heat Stress Conditions

Abstract Purpose The present research’s main objective was to explore the potential stimulative effect of fulvic acid (FA) as a soil conditioner and salicylic acid (SA) as foliar spraying on morpho-physio-biochemical attributes, fruit yield, and quality of ‘Sediek’ and ‘Ewais’ mango cultivars (cvs.) grown under saline calcareous soil and heat stress conditions Methods Eight treatments, namely, 200 (FA200) and 400 (FA400) g FA tree−1 as a soil addition, 200 (SA200) or 400 (SA400) mg SA L−1 as foliar spraying, and their bilateral combinations (e.g., FA200 + SA200, FA200 + SA400, FA400 + SA200, and FA400 + SA400) compared to untreated control on morpho-physio-biochemical attributes, yield, and fruit quality of ‘Sediek’ and ‘Ewais’ mango cvs. grown under saline calcareous soil and heat stress conditions were assessed. These treatments were carried out using a split-plot arrangement in a randomized complete block design replicated three times during the 2022 and 2023 seasons. Results Cultivar Sediek had higher SPAD value, leaf proline and phenolic content, leaf area, fruit weight, yield and vitamin C than Ewais which had higher tree water status and shoot length. Saline calcareous and heat-stressed mango trees without FA or/and SA treatment had a significant decline in their water status, photosynthetic traits, biochemical responses that adversely affected growth and yield and fruit quality. However, soil FA addition and foliar SA spraying alone or in combination at any application level attenuated the negative effects of saline calcareous and heat-stress conditions via enhancing the morpho-physio-biochemical attributes, positively reflecting in tree growth, yield, and fruit quality. FA treatment alone improved tree water status (membrane stability index; MSI and relative water content; RWC), photosynthetic traits (SPAD value and maximum photochemical efficiency; Fv/Fm), leaf area, fruit weight, fruit yield, and fruit vitamin C (fruit vit.C), while SA treatment alone enhanced leaf proline and phenolic content, shoot length, and fruit total soluble solids (fruit TSS) compared to the non-FA or SA-treated control. Moreover, co-application of FA400 and SA400 effectively alleviated the harmful impacts of dual stress of heat and salinity on mango trees by improving MSI, RWC, SPAD value, Fv/Fm, proline and phenolic content, fruit weight, fruit yield, fruit TSS, fruit vit.C by 19.7, 26.1, 46.7, 18.7, 101.7, 390.7, 42.7, 6.8, 22.6, 69.6% (averages of the two seasons), respectively, compared to the non-FA or SA-treated trees. Conclusion It is recommended to add 400 g FA tree−1 to soil integrated with 400 mg SA L−1 foliar spraying four times at 30-day intervals for improving water status and photosynthetic traits, proline and phenolic accumulation, thereby growth, yield, and fruit quality of mango trees exposed to dual stress of heat and salinity under arid conditions.

Tolerance of local gogo rice sprouts under salinity stress conditions

The expansion of rice planting areas in the future needs to be carried out outside Java, as fertile land in Java is shrinking due to land conversion. Most of the land outside Java consists of marginal land, such as areas with high salinity. High salinity levels in the soil cause a decrease in plant germination, growth, and production. The research aimed to examine the tolerance of each cultivar at each level of NaCl concentration, to obtain cultivars that were tolerant to salinity stress, and to determine the NaCl concentration that suppresses the germination of local upland rice. The research was structured using a completely randomized design with a two-factor factorial pattern. The first was the six upland rice cultivars, namely, dongan, jahara, Pulu Konta, pomegranate, kalendeng, and pulu tau leru, while the second factor was the NaCl concentration consisting of 0%, 0.2%, 0.4%, 0.6%, 0.8% and 1%. Thus, there were 36 experimental units, which were repeated three times so that there were 108 experimental units. The results of the research showed that there was no interaction with all germination variables; cultivar and concentration had a significant effect on maximum growth potential, germination capacity, germination time, plumule length, radicle length and dry weight of sprouts, while cultivar affected the wet weight of sprouts. Kalendeng has a high salinity tolerance. The use of NaCl concentrations of up to 0.6% has been able to reduce the germination capacity of local upland rice. The conclusion of the research showe that there was no interaction between all germination variables.

Mutual impact of salinity and climate change on crop production water footprint in a semi-arid agricultural watershed: Application of SWAT-MODFLOW-Salt

Sustainable agriculture in intensively irrigated watersheds, particularly those in arid and semi-arid regions, requires enhanced management practices to maintain crop production, which depends on climate, available water resources, soil conditions, irrigation practices, and crop type. Among these factors, soil salinity and climate change are significant challenges to agricultural productivity. To investigate the long-term influence of salinity and climate change on crop production from 1999 to 2100 in irrigated semi-arid regions, we apply the water footprint (WF) concept using the hydro-chemical watershed model SWAT-MODFLOW-Salt, driven by five General Circulation Models (GCMs) and two climate scenarios (RCP4.5 and RCP8.5), to a 732 km2 irrigated stream-aquifer system within the Lower Arkansas River Valley (LARV), Colorado, USA. The study focused on calculating the green (WFgreen), blue (WFblue), and total (WFtotal) crop production WFs for 29 crops in the region, with and without including salinity effect on crop yield. Results reveal that during the baseline period (1999–2009), the total annual average WFgreen, WFblue, and WFtotal increased by 7.6 %, 4.4 %, and 6.5 %, respectively, under salinity stress, as crops experienced reductions of up to 4.6 %, 1.6 %, and 2.3 % in green, blue, and total crop yield. The mutual impact of salinity and the worst-case climate model (IPSL_CM5A_MR) under the higher emission scenario (RCP8.5) led to a 3.3 %, 1.9 %, and 3 % increase in green, blue, and total crop production WFs. Furthermore, the study highlighted that the proportion of green, blue, and total crop production WFs in the LARV exceeded the world average. This discrepancy was attributed to various factors, including different spatial and temporal crop distribution, irrigation practices, soil types, and climate conditions. Notably, salinity stress affected green crop yield and green WF more significantly than blue crop yield and blue WF across all GCM models. This finding underscores the importance of prioritizing management practices to control salinity-associated challenges within the region.

Effects of salinity and nutrient stress on a toxic freshwater cyanobacterial community and its associated microbiome: An experimental study.

We aimed to evaluate the ability of naturally occurring colonies of Microcystis, embedded in a thick mucilage, to persist in estuarine waters. In two batch experiments, we examined the dynamics of microbial communities, including cyanobacteria and associated heterotrophic bacteria, sampled from the field during both a cyanobacterial bloom (non-limiting nutrient condition) and the post-bloom period (limiting nutrient condition), and subjected them to a salinity gradient representative of the freshwater-marine continuum. We demonstrated that both Microcystis aeruginosa and M. wesenbergii survived high salinities due to osmolyte accumulation. Specifically, prolonged exposure to high salinity led to betaine accumulation in the cyanobacterial biomass. The relative abundance of the mcyB gene remained around 30%, suggesting no selection for toxic genotypes with salinity or nutrient changes. Microcystins were predominantly intracellular, except at high salinity levels (>15), where more than 50% of the total microcystin concentration was extracellular. In both nutrient conditions, over 70% of the heterotrophic bacterial community belonged to the Gammaproteobacteria family, followed by the Bacteroidota. Bacterial community composition differed in both size fractions, as well as along the salinity gradient over time. Finally, genus-specific core microbiomes were identified and conserved even under highly stressful conditions, suggesting interactions that support community stability and resilience.

The evolutive role of shoot apical meristems in the adaptation of angiosperms to life at sea and the jump to potential environmental biotechnology applications

Seagrasses have adapted to a submerged lifestyle in seawater through a complex set of evolutionary processes. However, they show sensitivity to increases in natural salinity levels such as those commonly found in discharges of desalination plants, which have exponentially grown due to water scarcity in highly populated temperate areas, such as the Mediterranean basin. This study assessed the effects of brine-derived hypersalinity on the Mediterranean seagrass Posidonia oceanica, focusing on the metabolic responses of shoot apical meristems (SAMs). Although most physiological and genetic studies have used leaves, SAMs are more directly correlated with plant survival and might be more responsive to salinity stress. The experiments were: a controlled mesocosm of more than six practical salinity units (psu) over natural levels using either artificial salts or desalination brine and field transplantation experiments comparing two sites following the dilution plume of the brine (+5 and + 2 psu) with control. Hydrogen peroxide (H2O2), thiobarbituric acid reactive substances (TBARS), and ascorbate were measured to determine oxidative stress and damage, as well as relative expression of genes related to osmotic regulation and oxidative responses. Overall, relative expression of genes related to osmotic regulation (SOS1, SOS3, AKT 2/3) and oxidative stress (STRK1, CAT, MnSOD, FeSOD, APX, GR) was higher in SAMs at higher brine exposures, indicating a more active metabolic response in this organ. Similarly, reactive oxygen species (ROS) production and lipid peroxidation were higher closer to brine discharge and total ascorbate lower, indicating a correlative response with stressor intensity. These findings confirm that SAMs play an essential role in P. oceanica hypersalinity responses and its adaptation to life in the marine environment. Finally, the use of P. oceanica SAMs in this study is highly recommended for an early detection of threats caused by desalination brines that may cause physiological damage and meadow regression.

Comparative Transcriptomic Analyses Reveal Differences in the Responses of Diploid and Triploid Eastern Oysters to Environmental Stress.

Triploid oysters are commonly used as the basis for production in the aquaculture of eastern oysters along the USA East and Gulf of Mexico coasts. While they are valued for their rapid growth, incidents of triploid mortality during summer months have been well documented in eastern oysters, especially at low salinity sites. We compared global transcriptomic responses of diploid and triploid oysters bred from the same three maternal source populations at two different hatcheries and outplanted to a high (annual mean salinity = 19.4 ± 6.7) and low (annual mean salinity = 9.3 ± 5.0) salinity site. Oysters were sampled for gene expression at the onset of a mortality event in the summer of 2021 to identify triploid-specific gene expression patterns associated with low salinity sites, which ultimately experienced greater triploid mortality. We also examined chromosome-specific gene expression to test for instances of aneuploidy in experimental triploid oyster lines, another possible contributor to elevated mortality in triploids. We observed a strong effect of hatchery conditions (cohort) on triploid-specific mortality (field data) and a strong interactive effect of hatchery, ploidy, and outplant site on gene expression. At the low salinity site where triploid oysters experienced high mortality, we observed downregulation of transcripts related to calcium signaling, ciliary activity, and cell cycle checkpoints in triploids relative to diploids. These transcripts suggest dampening of the salinity stress response and problems during cell division as key cellular processes associated with elevated mortality risk in triploid oysters. No instances of aneuploidy were detected in our triploid oyster lines. Our results suggest that triploid oysters may be fundamentally less tolerant of rapid decreases in salinity, indicating that oyster farmers may need to limit the use of triploid oysters to sites with more stable salinity conditions.

Transcriptome signature of juvenile Litopenaeus vannamei cultured under different salinity levels in response to Vibrio harveyi infection

Although the widely cultured Litopenaeus vannamei is highly tolerant to varying salinity levels, the rapid fluctuation of abiotic and biotic factors due to climatic changes may become stressors to the shrimp's physiology, resulting in impaired immunity and increased disease susceptibility. This study aimed to investigate the combined effects of both factors towards L. vannamei at transcriptomic level. L. vannamei were cultured at three different salinity levels (5 ppt, 20 ppt and 30 ppt) for 60 days and were challenged with Vibrio harveyi. RNA-seq analysis was conducted on the hepatopancreas to assess the differential expressed genes (DEGs) in both control and V. harveyi infected groups. Our results revealed 5,725 DEGs was observed in shrimp reared at 5 ppt, 3,643 DEGs at 20 ppt and 1,560 DEGs at 30 ppt. Most DEGs were identified to be associated with osmoregulation and transport activities, immune and stress regulation, nutrient metabolism, growth, chitin binding, gonadal development, and metal ion binding and toxicity. We identified that shrimp cultured at intermediate salinity of 20 ppt exhibits the greatest immunity level after infection by V. harveyi, given that low salinity (5 ppt) may augment the free ion metal toxicity, resulting in higher disease susceptibility. Both V. harveyi and salinity stress function together or separately to activate a wide range of immune and stress regulatory genes, which could be potential candidate markers for future RNAi and knockdown research in developing efficient prophylactic management strategies for L. vannamei.

A Sustainable Methodological Approach for mitigation of Salt Stress of Rice Seedlings in Coastal Regions: Identification of Halotolerant Rhizobacteria from Noakhali, Bangladesh and their impact

Salinity hinders the growth of many crops common in the diet, such as rice, wheat and maize when cultivated in coastal salinity areas. Given the limited availability of cultivable land and the increasing growth of the population, it is necessary to enhance productivity. In this paper, we present an innovative approach to adopting Halotolerant Plant Growth Promoting Rhizobacteria (HPGPR) to enhance salt-tolerant rice varieties to solve salinity stress and enhance crop production. HPGPR has functions to overcome plant growth and development and is the most efficient bioinoculant for rice in saline environments. This approach can be considered a potential method because of the cost-effective and environmentally friendly impacts in agricultural production, which involves salt-affected areas.