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Copepods are among the most abundant organisms on the planet and play critical functions in aquatic ecosystems. Among copepods, populations of the Eurytemora affinis species complex are numerically dominant in many coastal habitats and serve as food sources for major fisheries. Intriguingly, certain populations possess the unusual capacity to invade novel salinities on rapid time scales. Despite their ecological importance, high-quality genomic resources have been absent for calanoid copepods, limiting our ability to comprehensively dissect the genome architecture underlying the highly invasive and adaptive capacity of certain populations. Here, we present the first chromosome-level genome of a calanoid copepod, from the Atlantic clade (Eurytemora carolleeae) of the E. affinis species complex. This genome was assembled using high-coverage PacBio long-read and Hi-C sequences of an inbred line, generated through 30 generations of full-sib mating. This genome, consisting of 529.3 Mb (contig N50 = 4.2 Mb, scaffold N50 = 140.6 Mb), was anchored onto four chromosomes. Genome annotation predicted 20,262 protein-coding genes, of which ion transport-related gene families were substantially expanded based on comparative analyses of 12 additional arthropod genomes. Also, we found genome-wide signatures of historical gene body methylation of the ion transport-related genes and the significant clustering of these genes on each chromosome. This genome represents one of the most contiguous copepod genomes to date and is among the highest quality marine invertebrate genomes. As such, this genome provides an invaluable resource to help yield fundamental insights into the ability of this copepod to adapt to rapidly changing environments.

Pericardial edema - fluid accumulation within the pericardium - is a frequently observed malformation in zebrafish embryo-based chemical toxicity screens. We recently discovered that the severity of triphenyl phosphate (TPHP)-induced pericardial edema was dependent on the ionic strength of exposure media. TPHP is an aryl phosphate ester (APE) widely used as a plasticizer and flame retardant. APEs are characterized by having one or more aryl groups bound to a phosphate center, with TPHP containing only unsubstituted aryl groups. Therefore, the objective of this study was to begin investigating whether, similar to TPHP, pericardial edema induced by other structurally related APEs is dependent on the ionic composition of exposure media. We first mined the peer-reviewed literature to identify other APEs that 1) induced pericardial edema in zebrafish embryos within a minimum of three peer-reviewed publications, and 2) demonstrated a statistically significant induction of pericardial edema in at least 70 % of the studies evaluated. Based on this meta-analysis, we identified four other APEs that caused pericardial edema in zebrafish embryos: isopropylated triphenyl phosphate (IPTPP), cresyl diphenyl phosphate (CDP), tricresyl phosphate (TMPP), and 2-ethylhexyl diphenyl phosphate (EDHPHP). Using TPHP as a positive control and pericardial edema as a readout, we developed concentration-response curves for all four APEs based on static exposure from 24 to 72 h post-fertilization (hpf). We then conducted co-exposures with D-Mannitol (an osmotic diuretic) and exposures within reverse osmosis (RO) water determine whether the ionic composition of exposure media mitigated APE-induced pericardial edema at 72 hpf. Using pericardial edema as an endpoint, the approximate EC50s for TPHP (positive control), IPTPP, CDP, TMPP, and EDHPHP were 6.25, 3.125, 3.125, 25, and 100 µM, respectively, based on exposure from 24 to 72 hpf. Interestingly, similar to our findings with TPHP, co-exposure with D-Mannitol and exposure within ion-deficient water significantly mitigated IPTPP- CDP-, TMPP-, and EDHPHP-induced pericardial edema in zebrafish embryos, suggesting that chemically-induced pericardial edema may be 1) dependent on the ionic composition of exposure media and 2) driven by a disruption in osmoregulation across the embryonic epidermis. Therefore, similar to other assay parameters, our findings underscore the need to standardize the osmolarity of exposure media in order to minimize the potential for false positive/negative hits in zebrafish embryo-based chemical toxicity screens conducted around the world.

This study investigated the effects of salinity, ammonia, and stocking density on Nile tilapia (Oreochromis niloticus) fingerlings over a 74-days. In three separate experiments, fingerlings (initial weight 25 ± 2.4 g) were exposed to salinity levels (5, 10, 15, and 20 ppt), ammonia concentrations (0.01, 0.02, 0.1, and 0.2 mg/L), and stocking densities (10, 15, 20, and 25 fish per 96 L aquarium). Survival, growth performance, biochemical parameters, and gene expression changes were assessed. Salinity ≥ 15 ppt and ammonia ≥ 0.1 mg/L significantly impaired growth (final weight, weight gain, specific growth rate, and feed efficiency) and increased mortality rates, reaching 37% and 56% at 20 ppt salinity and 0.2 mg/L ammonia, respectively. Elevated salinity and ammonia also caused significant increases in the activities of ALT, AST, LDH enzymes, along with higher serum glucose levels, while disrupting serum protein and ion concentrations, indicating considerable metabolic and osmoregulatory disturbances. At the molecular level, the expression of the growth-promoting IGF-I gene was down-regulated, while inflammatory marker TNFα was up-regulated, suggesting compromised health. Stocking density had less pronounced effects, though densities ≥ 20 fish/aquarium led to reduced growth, altered biochemical markers, and gene expression changes compared to 10–15 fish/aquarium. These findings establish salinity and ammonia tolerance thresholds for tilapia fingerlings, emphasize optimal stocking density, and provide insights into the physiological and molecular responses to multifactorial stressors. The study contributes to sustainable management strategies for tilapia aquaculture under variable environmental conditions. [ABSTRACT FROM AUTHOR]

Wheat (Triticum aestivum L.) is a globally important staple crop; however, its growth and yield are severely limited by drought stress. This study evaluated the effects of a combined microbial inoculant, Streptomyces pactum Act12 and Streptomyces rochei D74, on wheat photosynthesis, physiological traits, and yield under drought conditions. Key physiological and yield parameters were measured during the jointing, heading, and grain-filling stages. Drought stress significantly reduced chlorophyll content, maximum photochemical efficiency of photosystem II (PSII) (Fv/Fm), and antioxidant enzyme activities, while increasing malondialdehyde (MDA) levels, leading to a notable yield decline. In contrast, inoculation with Streptomyces strains alleviated these adverse effects, with the combined inoculant (Act12+D74) group demonstrating the most significant improvement. Chlorophyll content increased by up to 32.60%, Fv/Fm improved by 43.07%, and antioxidant enzyme activities were enhanced, with superoxide dismutase (SOD) activity increasing by 19.32% and peroxidase (POD) activity by 75.44%. Meanwhile, MDA levels were reduced by 61.61%. The proline content in the combined inoculant group increased by 90.44% at the jointing stage and the soluble protein content increased by 60.17% at the heading stage. Furthermore, it improved the yield by 26.19% by increasing both effective spikes and grains per spike. For the first time, this study revealed the synergistic effects of Act12 and D74 in enhancing photosynthesis, strengthening antioxidant defenses, and optimizing osmotic regulation under drought conditions. These findings provide a theoretical basis for developing environmentally friendly drought management strategies and highlight the potential applications of this inoculant in sustainable agriculture. [ABSTRACT FROM AUTHOR]

Acid invertases (Ac-Invs) are crucial enzymes in plant physiology, regulating sucrose metabolism and hydrolyzing sucrose into glucose and fructose. These sugars serve not only as energy sources and structural components but also as signaling molecules, influencing diverse developmental processes, including seed and fruit growth, flowering, and stress responses. Ac-Invs are classified into cell wall invertases (CWINs) and vacuolar invertases (VINs) based on their subcellular localization, with both playing distinct roles in sucrose unloading, osmotic regulation, and sugar accumulation. Recent studies have also highlighted their involvement in abiotic stress adaptation and hormonal regulation, emphasizing their central role in plant resilience and productivity. However, gaps remain in understanding their regulatory mechanisms, particularly their interactions with plant hormones, defective invertases, and responses to environmental stresses. This review summarizes the biochemical characteristics, functions, and regulatory mechanisms of Ac-Invs, providing insights into their evolutionary significance and potential applications in crop improvement. Future research directions are proposed to elucidate unresolved questions and leverage Ac-Invs for enhancing agricultural sustainability. [ABSTRACT FROM AUTHOR]

The negative effects of global warming also directly affect aquatic populations. Consequences such as evaporation due to chronic temperature increase, increase in salinity, and increase in stock density per unit volume are potential stress factors. While creating the trial design, an attempt was made to simulate the effects of global warming, especially on species living in salty and brackish water biotopes. In this study, changes in the gills of rainbow trout (Oncorhynchus mykiss) acclimated to 0, 20, and 38 ‰ of saline in the laboratory were examined histologically and immunohistochemically and blood serum osmolarity. In addition, the water temperature was changed, and experiments were carried out at 16, 19, and 22 °C for each salinity group in parallel with the increase in salinity. However, to simulate the decrease in water volume and intensive stocking due to the potential impact of climate change, the study was carried out using 15 fishes in low-volume aquariums (45 L). Tap water that had been kept for at least 3 days was used in the aquariums. To protect the water quality, independent aquariums with sponge filters were used, and since the aim was to keep dissolved oxygen low, no ventilation system other than the sponge filter was used. In order to minimize the deterioration in water quality during the trial, a 15% water change was performed by performing a bottom flush every 4 days and water of the same temperature and salinity was added as much as the reduced volume. In addition, since increasing stock density due to temperature increase and water decrease will cause the amount of dissolved oxygen to decrease, pure oxygen was not entered into any tank throughout the experiment, and the concentration was requested to be at a low level (7 ± 0.13 mg/L) in all groups. The trials were terminated at the end of the 71st day. Increased serum osmolarity values were observed due to the increase in salinity, and the highest serum osmolarity value was measured at 644 mOsm/kg in the 38 ‰ salinity group. Differences between the groups were found to be statistically significant (p < 0.05). It was observed that the number of cells containing Na+/K+-ATPase increased depending on salinity. Also, the number of chloride cells reached the maximum level in the 38 ‰ salinity group. Due to increasing salt levels, an increase in mucus cells, limited onset hyperplasia, aneurysm, lamellar separation, and necrosis were observed in the gill tissue. [ABSTRACT FROM AUTHOR]

Vivipary is common in several mangrove species and is generally considered an adaptation to the intertidal saline environment. However, the coexistence of many nonviviparous mangroves makes this view controversial. This study investigated the propagule development of two nonviviparous mangrove species, Sonneratia alba and S. caseolaris , with marked differences in salt tolerance and distribution. Changes in the density, water content, and concentrations of the five main osmoregulatory elements (Cl, Na, K, Ca, and Mg) were determined. As the propagules of S. alba and S. caseolaris mature, the element concentrations (mg/g) in the propagules gradually decrease, indicating a desalination process. Moreover, the Cl, Na, Ca, and Mg content in the propagules were lower than in the mature leaves and calyx. Similar to viviparous mangroves, the development of the propagules of nonviviparous mangroves is also a desalination process. Although both viviparous and nonviviparous mangrove species undergo a desalination process during propagule development, our findings suggest that viviparity may not be solely defined by desalination, but rather by the extended period of low-salinity protection during early development on the maternal tree, which represents a key adaptation for survival in high-salinity environments. In contrast, nonviviparous mangroves, which rely on seed germination and early development in saline seawater, face additional challenges in high-salinity habitats, highlighting their distinct adaptive strategies. [ABSTRACT FROM AUTHOR]

Late embryogenesis abundant (LEA) proteins are a class of proteins associated with osmotic regulation and plant tolerance to abiotic stress. However, studies on the LEA gene family in the alpine cold-tolerant herb are still limited, and the phylogenetic evolution and biological functions of its family members remain unclear. In this study, we conducted genome-wide identification, phylogenetic evolution, and abiotic stress response analyses of LEA family genes in Notopterygium species, alpine cold-tolerant medicinal herbs in the Qinghai–Tibet Plateau and adjacent regions. The gene family identification analysis showed that 23, 20, and 20 LEA genes were identified in three Notopterygium species, N. franchetii, N. incisum, and N. forrestii, respectively. All of these genes can be classified into six LEA subfamilies: LEA_1, LEA_2, LEA_5, LEA_6, DHN (Dehydrin), and SMP (seed maturation protein). The LEA proteins in the three Notopterygium species exhibited significant variations in the number of amino acids, physical and chemical properties, subcellular localization, and secondary structure characteristics, primarily demonstrating high hydrophilicity, different stability, and specific subcellular distribution patterns. Meanwhile, we found that the members of the same LEA subfamily shared similar exon–intron structures and conserved motifs. Interestingly, the chromosome distributions of LEA genes in Notopterygium species were scattered. The results of the collinearity analysis indicate that the expansion of the LEA gene family is primarily driven by gene duplication. A Ka/Ks analysis showed that paralogous gene pairs were under negative selection in Notopterygium species. A promoter cis-acting element analysis showed that most LEA genes possessed multiple cis-elements connected to plant growth and development, stress response, and plant hormone signal transduction. An expression pattern analysis demonstrated the species-specific and tissue-specific expression of NinLEAs. Experiments on abiotic stress responses indicated that the NinLEAs play a crucial role in the response to high-temperature and drought stresses in N. franchetii leaves and roots. These results provide novel insights for further understanding the functions of the LEA gene family in the alpine cold-tolerant Notopterygium species and also offer a scientific basis for in-depth research on the abiotic stress response mechanisms and stress-resistant breeding. [ABSTRACT FROM AUTHOR]

Grain legumes are a rich source of dietary proteins and hence are essential for achieving food and nutritional security, worldwide. Grain legumes are negatively affected by salt stress, which results in decreased growth, yield, productivity, and other financial losses. Salt stress causes severe phytotoxicities, like specific ion toxicities, hormonal and nutritional imbalances, disruptions of stomatal conductance, and alterations in leaf water potential and rate of photosynthesis. To enhance agricultural productivity under salt stress conditions, several ecofriendly methods have been tried recently. Out of these, the use of biostimulants gained particular attention due to their ease of availability and high-stress ameliorative potential. It includes the use of non-microbial biostimulants like humic acid and seaweed extracts (SWE), as well as microbial biostimulants like mycorrhiza, plant growth-promoting and nitrogen-fixing bacteria, which promote plant growth and development. Biostimulants successfully alleviate salt stress-induced toxicities in legumes, when introduced either alone or in combination with other macro- or microorganisms in the soil. In response to salinity, plants raise their cellular levels of osmolytes (proline and glycine betaine) and polyamines, as well as phytohormones. The application of biostimulants in grain legumes alleviates the salt stress-induced toxicity by improving the seed germination, seedling growth, rate of photosynthesis, nitrogen fixation, absorption and uptake of minerals, grain development, yield, ROS homeostasis and osmoregulation. Many of the reviews have lacked the assessment of the effect of these ecofriendly biostimulants on mitigation of salt stress in grain legumes. The development of integrated, eco-friendly and sustainable use of various biostimulants and their mode of action in managing salt stress in legume production is discussed in the present review. [ABSTRACT FROM AUTHOR]

Soil salinization severely restricts the growth and development of crops globally, especially in the northwest Loess Plateau, where apples constitute a pillar industry. Nanomaterials, leveraging their unique properties, can facilitate the transport of nutrients to crops, thereby enhancing plant growth and development under stress conditions. To investigate the effects of nano zinc oxide (ZnO NP) on the growth and physiological characteristics of apple self-rooted rootstock M9-T337 seedlings under saline alkali stress, one-year-old M9-T337 seedlings were used as experimental materials and ZnO NPs were used as donors for pot experiment. Six treatments were set up: CK (normal growth), SA (saline alkali stress,100 mmol/L NaCl + NaHCO3), T1 (saline alkali stress + 50 mg/L ZnO NPs), T2 (saline alkali stress + 100 mg/L ZnO NPs), T3 (saline alkali stress + 150 mg/L ZnO NPs) and T4 (saline alkali stress + 200 mg/L ZnO NPs). The results were found to show that saline alkali stress could significantly inhibit the growth and development of M9-T337 seedlings, reduce photosynthetic characteristics, and cause ion accumulation to trigger osmotic regulation system, endogenous hormone and antioxidant system imbalances. However, the biomass, plant height, stem diameter, total leaf area and leaf perimeter of M9-T337 seedlings were significantly increased after ZnO NP treatment. Specifically speaking, ZnO NPs can improve the photosynthetic capacity of M9-T337 by increasing the content of photosynthetic pigment, regulating photosynthetic intensity and chlorophyll fluorescence parameters. ZnO NPs can balance the osmotic adjustment system by increasing the contents of soluble protein (SP), soluble sugar (SS), proline (Pro) and starch, and can also enhance the activities of enzymatic (SOD, POD, and CAT) and non-enzymatic antioxidant enzymes (APX, AAO, GR, and MDHAR) to enhance the scavenging ability of reactive oxygen species (H2O2, O2•−), ultimately reducing oxidative damage; ZnO NPs promoted the growth of M9-T337 seedlings under saline alkali stress by synergistically responding to auxin (IAA), gibberellin (GA3), zeatin (ZT) and abscisic acid (ABA). Additionally, the Na+/K+ ratio was reduced by upregulating the expression of Na+ transporter genes (MdCAX5, MdCHX15, MdSOS1, and MdALT1) and downregulating the expression of K+ transporter genes (MdSKOR and MdNHX4). After comprehensive analysis of principal components and correlation, T3 (150 mg/L ZnO NPs) treatment possessed the best mitigation effect. In summary, 150 mg/L ZnO NPs(T3) can effectively maintain the hormone balance, osmotic balance and ion balance of plant cells by promoting the photosynthetic capacity of M9-T337 seedlings, and enhance the antioxidant defense mechanism, thereby improving the saline alkaline tolerance of M9-T337 seedlings. [ABSTRACT FROM AUTHOR]

Plants have large amounts of the late embryogenesis abundant protein (LEA) family of proteins, which is involved in osmotic regulation. The Korla Pear (Pyrus sinkiangensis Yu) is an uncommon pear species that thrives in Xinjiang and can survive below-freezing conditions. We found that the PsLEA4 gene was more expressed after cold treatment by looking at the transcriptome data of the Korla Pear. In order to evaluate the biological function of the PsLEA4 protein under low-temperature stress and its potential for use in agricultural breeding, we cloned the PsLEA4 gene from the Korla Pear, made a plant overexpression vector, and transformed it into a tomato via Agrobacterium transformation. When exposed to low temperatures, we found that PsLEA4 overexpression can regulate proline metabolism and antioxidant enzyme activity in tomatoes compared to wild tomatoes. Because of this, transgenic tomatoes are more resilient to cold temperatures and produce more than their wild counterparts. Thus, expressing PsLEA4 has multiple advantages: (1) Improving frost resistance and reducing plant damage. (2) Increasing crop yield. Therefore, this study provides a theoretical basis for the role of the PsLEA4 protein in plants' resilience to low temperatures, as well as for its potential application in crop breeding. [ABSTRACT FROM AUTHOR]

Marine teleosts experience ion gain and water loss in their natural habitats. Among other tissues, the urinary bladder epithelium of marine fishes has been shown to actively transport ions to facilitate water absorption. However, transport properties of the urinary bladder epithelium of marine fishes and its plasticity in altered ambient salinities is relatively under-investigated. We describe urinary bladder epithelium electrophysiology, water flux, and expressions of ion transporters in urinary bladder tissue of Gulf toadfish (Opsanus beta) acclimated to either 35 ppt or 60 ppt seawater. Water absorption in bladder sac preparations increased ∼350% upon acclimation to 60 ppt. Increases in water transport coincided with a significant ∼137% increase in urinary bladder tissue mucosal-to-serosal short circuit current (Isc) and a ∼56% decrease in tissue membrane resistance. Collectively, these metrics indicate that an active electrogenic system facilitates water absorption via Na+ (and Cl−) transport in urinary bladder tissue. Furthermore, pharmacological inhibition of urinary bladder tissue Isc and expression of a suite of ion transporters and channels previously unidentified in this tissue provide mechanistic insights into the transport processes responsible for water flux. Analysis of water transport to overall Gulf toadfish water balance reveals a modest water conservation role for the urinary bladder of ∼0.5% of total water absorption in 35 ppt and 1.9% in 60 ppt acclimated toadfish. These results emphasize that electrogenic ion transport facilitates water-absorptive properties of the urinary bladder in Gulf toadfish—a process that is regulated to facilitate water homeostasis. NEW & NOTEWORTHY: Novel experiments showcasing increased urinary bladder water absorption, ion transport, and altered channel/transporter expression in a marine fish acclimated to high salinities. Our results provide additional and noteworthy mechanistic insight into the ionoregulatory processes controlling water transport at the level of the urinary bladder in marine teleosts. Experimental outcomes are applied to whole organism-level water transport values, and the relative importance of marine teleost urinary bladder function to overall organism water conservatory measures is discussed. [ABSTRACT FROM AUTHOR]

Simple Summary: The razor clam Sinonovacula constricta, a commercially valuable marine bivalve species, is typically found in estuaries and coastal mudflat areas. However, limited research has been conducted on their adaptation mechanisms to high salinity stress. The present study provides the first comprehensive analysis of the members, gene structure, chromosome location, systematic evolution, and expression characteristics of the ALDH family in S. constricta following acute high salt stress. In this study, a total of 16 ScALDH genes were identified. Under acute salt stress, the expression of 14 members of the ScALDH family significantly changed, compared with when they were at 0 h, suggesting that the ScALDH gene family plays a crucial role in facilitating the regulation of osmotic pressure under salinity stress and adaptation. This study elucidated the gene characteristics, systematic evolution, and response to acute high salt stress of the ScALDH family, contributing valuable data to the understanding of the ALDH gene family in bivalves and providing a reference for further exploration into their role in osmotic stress regulation. The razor clam Sinonovacula constricta, a significant marine bivalve species, inhabits estuaries and encounters salinity stress. Despite its commercial importance, there is limited understanding of its adaptive mechanisms to high salinity. Aldehyde dehydrogenases (ALDHs), which belong to the NAD(P)+-dependent superfamily, play a crucial role in stress resilience by participating in catabolic and anabolic pathways, such as carnitine synthesis, glycolysis, and amino acid metabolism. This study presents the first comprehensive analysis of the ALDH family in S. constricta under acute high salt stress conditions and identifies 16 ScALDH genes across 10 subfamilies. These genes are located on eight chromosomes, with tandem duplications observed on chromosome 10; they encode mostly acidic and hydrophilic proteins. Among them, ScALDH18A1 contains a conserved P5CS domain that is implicated in proline synthesis and osmotic regulation. The expression of 14 ScALDH members were significantly altered under acute salt stress conditions, with ScALDH8 and ScALDH18A1 showing increased expression levels, suggesting their involvement in osmotic pressure regulation. This research provides insights into the characteristics, evolution, and response to salinity stress of the ScALDH gene family while shedding light on ALDH function in bivalves, as well as serving as a foundation for further studies on osmotic stress regulation. [ABSTRACT FROM AUTHOR]

The purpose of this study was to investigate the effects of biostimulants on increasing the adaptive mechanisms of pea (Pisum sativum L.) under water deficit conditions, with an emphasis on optimising physiological functions, biochemical processes, and morphological development of plants. The experiment was conducted under controlled conditions that helped to accurately model the effect of water stress. The study used comprehensive evaluation methods, including physiological parameters (photosynthetic activity, transpiration), biochemical markers (antioxidant enzyme activity, proline level), and morphological parameters (length and weight of the root system). The findings confirmed that treatment with biostimulants significantly increased the adaptive potential of plants. Photosynthetic activity in the treated plants was 82%, which was substantially higher than in the control group, where this level reached only 60%. Transpiration in the treated plants stayed stable, ensuring optimised water balance even under stress. Biochemical analysis showed that the activity of superoxide dismutase and catalase in plants treated with biostimulants increased by 145% compared to control plants, which contributed to a major reduction in oxidative stress. The level of proline, as a key osmotic regulator, was also significantly higher in the treated plants, which maintained the stability of the cellular water balance. Morphological studies revealed that the plants treated with biostimulants had a more developed root system: the length of the roots was 10 cm longer, while the weight was greater than in the control. This helped the plants to use moisture from deeper soil layers, which improved their resistance to drought. As a result, the yield loss in the treated plants was half that of the control group. These findings highlighted the effectiveness of using biostimulants to increase pea resistance to water deficit and maintain productivity. This makes the proposed approach promising for implementation in agricultural technology, especially in arid regions where water deficit is the primary limiting factor for crops [ABSTRACT FROM AUTHOR]

Salinity stress is a major challenge for global agriculture, particularly in arid and semi-arid regions, limiting plant productivity due to water and soil salinity. These conditions particularly affect countries along the southern Mediterranean rim, including Algeria, which primarily focuses on pastoral and forage practices. This study investigates salinity tolerance and ecotypic variability in Vicia narbonensis L., a fodder legume species recognized for its potential to reclaim marginal soils. Morphological, physiological, and biochemical responses were assessed in three ecotypes (eco2, eco9, and eco10) exposed to different salinity levels (low, moderate, and severe). The study was conducted using a completely randomized block design with three blocks per ecotype per dose. The results from the two-way analysis of variance demonstrate significant effects across nearly all attributes studied, revealing distinct ecotypic responses. These findings underscore variations in growth parameters, osmotic regulation mechanisms, and biochemical adjustments. The substantial diversity observed among these ecotypes in their response to salinity provides valuable insights for breeders addressing both agronomic and ecological challenges. Multivariate analyses, including Principal Component Analysis (PCA), revealed key variables distinguishing between ecotypes under salinity stress. Moreover, Classification based on Salinity Tolerance Indices (STI) further differentiated ecotypic performance with more precision, and this is because of the combination of the different parameters studied. These results open up new prospects for the development of strategies to improve the salinity tolerance of forage legumes. [ABSTRACT FROM AUTHOR]

Summary: In theory, there is a trade‐off between hydraulic efficiency and safety. However, the strength and direction of this trade‐off at the leaf level are not consistent across studies, and habitat climate may impact this trade‐off.We compiled a leaf hydraulic efficiency and safety dataset for 362 species from 81 sites world‐wide, with 280 paired observations of both traits, and tested whether climate was associated with departure from the proposed trade‐off.The leaf hydraulic efficiency–safety trade‐off was weak (R2 = 0.144) at the global scale. Mean annual precipitation and solar radiation (SR) modified the trade‐off. Species from dry and high SR habitats (e.g. desert and tropical savanna) were generally located above the trade‐off line, indicating that these species tended to have higher leaf hydraulic safety and efficiency than species from wet habitats with low SR (e.g. subtropical monsoon forest and montane rainforest), which were located below the trade‐off line. Leaves with high vein density, dry leaf mass per area, and osmotic regulation enhanced safety without compromising hydraulic efficiency.Variation in the hydraulic efficiency–safety trade‐off at the leaf level likely facilitates plant survival in specific habitats and allows for a more nuanced view of leaf hydraulic adaption strategies at the global scale. [ABSTRACT FROM AUTHOR]

To clarify the differences between migratory and non‐migratory salmonids during the parr‐smolt transformation, we conducted experiments on steelhead (SH) and rainbow trout (RT) Oncorhynchus mykiss. We examined relationships among different parameters of osmoregulatory, endocrine, immune, and stress‐related regulation in these fish following free selection of salinities. For this, we used an experimental halocline aquarium in which the upper layer was filled with fresh water and the lower with seawater. There was no significant difference between the two trout strains in terms of the number of fish in the final positions after the overnight trial. However, the time spent by each fish in the lower tank during the overnight trial was significantly longer in SH than in RT. Additionally, the time spent by each fish in the lower tank and plasma cortisol concentration were significantly correlated in RT, but not in SH. Similarly, plasma osmolality after the trial had a significant positive correlation with plasma cortisol concentration in RT, but not in SH. The plasma cortisol and mRNA levels of sodium‐potassium ATPase‐α3 in the gill were negatively correlated, as were several types of cortisol receptors in the gill and brain, in RT. Meanwhile, the genes expressed in SH were positively correlated with plasma cortisol. In SH, plasma cortisol was also significantly correlated with immune and stress‐related factors, which was not seen in RT. Our results suggest that the studied factors are important to behavioral and physiological differences in anadromy among salmonid species. [ABSTRACT FROM AUTHOR]

The study of prolactin function evolution provides key insights into the diverse effects of this hormone in mammals, both in health and disease, which is relevant from both theoretical and practical perspectives. This article reviews both original and literature data concerning the role of prolactin and its receptors in regulating the sexual dimorphism of freshwater adaptation in the three-spined stickleback Gasterosteus aculeatus L. The mRNA (messenger RNA) expression of prolactin 1 gene (one of two prolactin paralogs) and of its receptor PRLRA (prolactin receptor A) in the brain increase only in female sticklebacks upon transition to fresh water. The brain and kidney of the stickleback are androgen-dependent organs characterized by sex-dependent expression of Prlra (prolactin receptor A gene) under seawater conditions. It is assumed that sex-dependent osmoregulatory effects of prolactin are realized through the PRLRA receptors in these organs. The PRLRB (prolactin receptor B) receptors are expressed in the kidney and brain of sticklebacks under seawater conditions regardless of sex, but the expression of these receptors is more sensitive to decrease in water salinity. Apparently, the PRLRB receptors participate more actively in the implementation of sex-independent osmoregulatory functions of prolactin. The gills and intestine are osmoregulatory organs expressing the PRLRA and PRLRB receptors regardless of sex in both seawater and freshwater. During freshwater adaptation of stickleback females, the expression of prolactin 1 gene Prl1 in the brain and the expression of Atp1a1 (α1a subunit of Na+/K+-ATPase), Nhe3 (sodium-proton antiport gene NHE3), and Ecac (epithelial calcium channel gene) in their gills increase concurrently. It is assumed that these gill genes are under the positive control of prolactin. Exploring the potential for prolactin osmoregulatory function in mammals brings to the idea that this hormone may manifest itself under conditions of certain pathologies accompanied by increased expression of prolactin receptor isoforms in osmoregulatory organs, such as cholestasis in female rats. The latter is accompanied by expression of Prlr (prolactin receptor gene) isoforms' increase and by the changes in the activity and ratio of Na+/K+-ATPase subunits in the kidneys. It is assumed that the osmoregulatory function of prolactin in fish is sex-dependent; in mammals, it may manifest itself at disrupted water-salt exchange. [ABSTRACT FROM AUTHOR]

Soil salinity is one of the main challenges that modern agriculture faces. Avocado, which is classified as a glycophyte, is very sensitive to salt stress. There are botanical varieties of avocado that differ in their salt tolerance. This study investigated how salt stress affects the in vitro germination of two avocado botanical varieties americana (West Indian breed) and drymifolia (Mexican native) with different salt tolerances. This study also assessed the potential role of the avocado PaHAK2 high-affinity K+ transporter HAK/KUP/KT in response to saline stress during germination. Salinity (60 mM NaCl) delayed the germination speed of the drymifolia variety relative to the americana variety. A computational 3D inference protein model of the PaHAK2 protein showed 10 highly conserved transmembrane domains. During the imbibition period, there was a differential increase in the expression of the PaHAK2 gene at 60 mM NaCl in both varieties, which suggests the presence of osmotic adjustment and regulation. The enhanced expression of PaHAK2 in the americana variety suggests an adaptive advantage to salinity. We conclude that PaHAK2 participates in the response of avocado to salt stress during seed germination. [ABSTRACT FROM AUTHOR]

Coconut holds significant importance as a fruit and oilseed crop in tropical and subtropical regions. However, low-temperature (LT) stress has caused substantial reductions in yield and economics and impedes coconut production, therefore constraining its widespread cultivation and utilization. The appropriate application of potassium (K) has the potential to enhance the cold tolerance of crops and mitigate cold damage, but the regulatory mechanisms by which K improves coconut adaptability to cold stress remain poorly understood. Transcriptome and metabolomic analyses were performed on coconut seedlings treated with LT (5 °C) and room temperature (25 °C) under various K conditions: K0 (0.1 mM KCL), KL (2 mM KCL), KM (4 mM KCL), and KH (8 mM KCL). Correlation analysis with physiological indicators was also conducted. The findings indicated that K absorption, nutrient or osmotic regulation, accumulation of substances, photosynthesis, hormone metabolism, and reactive oxygen species (ROS) clearance pathways played crucial roles in the adaptation of coconut seedlings to LT stress. LT stress disrupted the homeostasis of hormones, antioxidant enzyme activity, chlorophyll, K, and the regulation of nutrients and osmolytes. This stress also leads to the downregulation of genes and metabolites related to K transporters, hormone metabolism, transcription factors, and the metabolism of nutrients and osmolytes. Applying K helped maintain the homeostasis of hormones, antioxidant enzyme activity, chlorophyll, K, and the regulation of nutrients and osmolytes, promoted the removal of ROS, and reduced malondialdehyde, consequently diminishing the damage caused by LT stress to coconut seedlings. Furthermore, the comprehensive analysis of metabolomics and transcriptomics highlighted the importance of carbohydrate metabolism, biosynthesis of other secondary metabolites, amino acid metabolism, lipid metabolism, and ABC transporters in K's role in improving coconut seedlings' tolerance to LT stress. This study identified the pivotal biological pathways, regulatory genes, and metabolites implicated in K regulation of coconut seedlings to acclimate to LT stress. [ABSTRACT FROM AUTHOR]

Sunflower (Helianthus annuus L.) is an important oilseed crop cultivated extensively across the globe. High salinity adversely impacts plant growth and physiological processes. In this study, the data on the phenotypes, physiological indices, and expression of relevant genes from different pathways responding to the stress were collected to clarify the physiological mechanisms underlying sunflower's salt tolerance with the seedlings of two salt-tolerant (182265 and 182283) and two salt-sensitive (182093 and 186096) genotypes, which were exposed to 350 mM NaCl for 5 days. The findings revealed that, during the seedling stage, salt-tolerant sunflowers accumulated less Na+ and more K+, resulting in a higher K+/Na+ ratio that mitigated ionic toxicity throughout the plants, compared to the salt-sensitive resources. Furthermore, the salt-tolerant germplasms also exerted salt tolerance through the following several pathways: they maintained robust osmotic regulation by accumulating higher levels of proline, soluble sugars, and other osmolytes; they neutralized reactive oxygen species (ROS) by elevating the activity of antioxidant enzymes such as POD, SOD, CAT, APX, and GR; and they sustained optimal growth by boosting photosynthesis. Taken together, this study provided a more comprehensive assessment of the sunflower's physiological salt tolerance, providing insights that will inform further molecular studies on salt tolerance and accelerating the breeding process for sunflower varieties with improved salt resilience. [ABSTRACT FROM AUTHOR]

Winter rapeseed is a high-oil crop that exhibits significant sensitivity to low temperatures, leading to a substantial reduction in production. Hence, it is of great significance to elucidate the genomic genetic mechanism of strong freezing-resistant winter rapeseed to improve their freezing-resistant traits. In this study, global transcriptome expression profiles of the freezing-resistant cultivar NTS57 (NS) under freezing stress were obtained for the years 2015, 2016, and 2017 by RNA sequencing (RNA-seq). Most differentially expressed genes (DEGs) were involved in the plant hormone signal transduction, alpha-linolenic acid metabolism, protein processing, glutathione metabolism, and plant-pathogen interaction pathways. Antioxidant enzyme activities and lipid peroxidation levels were significantly positively and negatively correlated with overwintering rate (OWR), respectively. After freezing treatment, the formation of freezing resistance of NS was attributed to the increase in antioxidant enzyme activities and content of osmotic regulation substances, as well as the decrease in lipid peroxidation level. Furthermore, quantitative reverse transcription polymerase chain reaction (qRT-PCR) and phenotypic verification indicated that heat stress transcription factor A2 (HSFA2) and 17.6 kDa class II heat shock protein (HSP17.6) participated in the response to freezing stress. This study will further refine the regulatory network of plants against freezing stress and help to screen candidate genes for improving plant freezing resistance. [ABSTRACT FROM AUTHOR]

This study investigates the physiological responses of three grapevine cultivars to salt stress. Cuttings from cv. 'Sultana seedless', cv. 'Hamburg muscat' and the local variety cv. 'Ercis uzumu', were utilized. After rooting, the cuttings were brought to the vegetative stage with a single internode before subjecting them to salt treatments. Salt stress was induced using NaCl solutions at concentrations of 0, 50, and 100 mM at four-day intervals. Throughout the experiment, various physiological parameters were assessed, including ion homeostasis, osmotic regulation, antioxidant activity, and mineral uptake in different plant tissues. Our findings revealed significant variations in salt tolerance among the tested grapevine cultivars. Specifically, cv. 'Ercis uzumu' exhibited robust physiological responses to salt stress, indicating high tolerance, while cv. 'Sultana seedless' demonstrated moderate responses, and cv. 'Hamburg muscat' displayed heightened sensitivity to salt stress at the physiological level. [ABSTRACT FROM AUTHOR]

Many flatfish species are partially euryhaline, such as the Pacific sanddab which spawn and feed in highly dynamic estuaries ranging from seawater to near freshwater. With the rapid increase in saltwater invasion of freshwater habitats, it is very likely that in these estuaries, flatfish will be exposed to increasing levels of dissolved organic carbon (DOC) of freshwater origin at a range of salinities. As salinity fluctuations often coincide with changes in DOC concentration, two natural freshwater DOCs [Luther Marsh (LM, allochthonous) and Lake Ontario (LO, autochthonous) were investigated at salinities of 30 and 7.5 ppt. Optical characterization of the two natural DOC sources indicate salinity-dependent differences in their physicochemistry. LO and LM DOCs, as well as three model compounds [tannic acid (TA), sodium dodecyl sulfate (SDS) and bovine serum albumin (BSA)] representing key chemical moieties of DOC, were used to evaluate physiological effects on sanddabs. In the absence of added DOC, an acute decrease in salinity resulted in an increase in diffusive water flux (a proxy for transcellular water permeability), ammonia excretion and a change in TEP from positive (inside) to negative (inside). The effects of DOC (10 mg C L-1) were salinity and source-dependent, with generally more pronounced effects at 30 than 7.5 ppt, and greater potency of LM relative to LO. Both LM DOC and SDS increased diffusive water flux at 30 ppt but only SDS had an effect at 7.5 ppt. TA decreased ammonia excretion at 7.5 ppt. LO DOC decreased urea-N excretion at both salinities whereas the stimulatory effect of BSA occurred only at 30 ppt. Likewise, the effects of LM DOC and BSA to reduce TEP were present at 30 ppt but not 7.5 ppt. None of the treatments affected oxygen consumption rates. Our results demonstrate that DOCs and salinity interact to alter key physiological processes in marine flatfish, reflecting changes in both gill function and the physicochemistry of DOCs between 30 and 7.5 ppt. [ABSTRACT FROM AUTHOR]

The previously available coding region for the spiny dogfish (Squalus acanthias) AQP3-2 gene was amplified from cDNAs using PCR. Agarose gel electrophoresis gave a band of the AQP3-2 coding region, as well as multiple smaller splice variant bands. The main AQP3-2 band and the largest and most fluorescently intense pair of these splice variant bands were cloned and sequenced. Amplifications were performed on a range of tissue cDNAs, but AQP3-2 was only expressed in the kidney and brain. Quantitative PCR amplifications using pre-existing kidney cDNA from an environmental salinity acclimation experiment showed that the abundance of mRNA from both the main AQP3-2 transcript and the largest splice variant (Splice Variant 1) was lower in 120% seawater (SW) acclimated fish, although only the values for Splice Variant 1 were statistically significant. A custom-made affinity-purified rabbit polyclonal AQP3-2 antibody was produced, and this gave four bands of around the correct sizes (which were 27 and 32 kDa) for the complete AQP3-2 and Splice Variant 1 proteins. Two of the bands may have been N-glycosylated forms of these proteins. Other bands were also present on the Western blot. No bands were present when the antibody was pre-blocked by the peptide antigen. In tissue sections of the dogfish kidney, immunohistochemical localization experiments showed that AQP3-2 was expressed in the early distal tubule (EDT) and late distal tubule (LDT) nephron segments. The results suggest that AQP3-2 may be involved in cell volume regulation in the EDT and water and urea absorption in the LDT nephron segment. [ABSTRACT FROM AUTHOR]

Ustilago esculenta is a dimorphic fungus that specifically infects Zizania latifolia, causing stem swelling and the formation of an edible fleshy stem known as jiaobai. The pathogenicity of U. esculenta is closely associated with the development of jiaobai and phenotypic differentiation. Msb2 acts as a key upstream sensor in the MAPK (mitogen-activated protein kinase) signaling pathway, playing critical roles in fungal hyphal growth, osmotic regulation, maintenance of cell wall integrity, temperature adaptation, and pathogenicity. In this study, we cloned the UeMsb2 gene from U. esculenta (GenBank No. MW768949). The open reading frame of UeMsb2 is 3015 bp in length, lacks introns, encodes a 1004-amino-acid protein with a conserved serine-rich domain, and is localized to the vacuole. Expression analysis revealed that UeMsb2 is inducibly expressed during both hyphal growth and infection processes. Deletion of UeMsb2 did not affect haploid morphology or growth rate in vitro but significantly impaired the strain's mating ability, suppressed filamentous growth, slowed host infection progression, and downregulated the expression of b signaling pathway genes associated with pathogenicity. Notably, the deletion of UeMsb2 did not influence the in vitro growth of U. esculenta under hyperosmotic, thermal, or oxidative stress conditions. These findings underscore the critical role of UeMsb2 in regulating the pathogenicity of U. esculenta. This study provides insights into the interaction between U. esculenta and Z. latifolia, particularly the mechanisms that drive host stem swelling. [ABSTRACT FROM AUTHOR]

Aim: As an environment friendly regulating factor, acetic acid (AA) plays an important role in linking basic physiological progresses and hormone signaling. Methods: In this study, seedlings of Cunninghamia lanceolate collected from two different rainfall regions were used to explore the effects of exogenous AA. Results: The results indicated that exogenous AA (200 mM) could eliminate drought-induced damages. The application of AA to soils could induce needle abscisic acid accumulation to decrease stomatal conductance and transpiration rate and further lead to the maintenance of needle water content and water use efficiency. Meanwhile, AA promotes the photosynthetic activity and photo-protection by increasing the contents of chlorophyll pigments and the activity of PSII reaction center. The alleviation of electrolyte leakage and malondialdehyde induced by drought, accompanied by the enhancement of the ROS scavenging system and osmotic regulation indicated that AA could protect cell membrane and eliminate oxidative toxicity. Additionally, this work further showed the provenance-specific responses to exogenous AA and demonstrated the feasibility of exogenous AA in larger pot experiments for woody plants. Conclusion: Overall, our study provides evidence that exogenous AA can strengthen the ability of C. lanceolate seedlings against drought as a positive regulator. Therefore, the irrigation of appropriate doses of AA into soils can be an effective practice against drought for Chinese fir forests. [ABSTRACT FROM AUTHOR]