Search Results (294)

Aphids are sap-sucking pests that cause substantial damage to fruit and fibre crops through direct feeding and transmission of plant viruses. While chemical pesticides remain the primary method of control, their use raises concerns related to human health, environmental contamination, pesticide resistance, and impacts on beneficial insects. As a sustainable alternative, spray-on double-stranded RNA (dsRNA) technology offers a promising approach to induce RNA interference (RNAi) in target pests. For RNAi to be effective against sap-sucking insects like the green peach aphid (Myzus persicae), it is essential to identify genes whose silencing disrupts vital physiological functions. In this study, artificial diet (AD)-based feeding assays were used to evaluate dsRNAs targeting eight genes involved in neural function, osmoregulation, feeding behaviour, and nucleic acid/protein metabolism. dsRNAs were administered individually, in combinations, or as a multi-target stacked construct. After 98 h of feeding, aphid mortality ranged from 14 to 72% (individual targets), 78–85% (combinations), and 54% (stacked construct). Transcript knockdown varied from 6.3% to ~54%, though a consistent correlation with mortality was not always observed. The gene targets and combinatorial dsRNA strategies identified in this study provide a foundation for developing RNAi-based crop protection technologies against M. persicae infestation. Full article

Cucumis sativus L. is a globally important vegetable crop that occupies a significant position in protected agriculture due to its high nutritional value, short cultivation cycle, and considerable economic benefits. As a cold-sensitive plant, however, cucumber is highly susceptible to low-temperature stress. which can severely inhibit growth and development, hinder seed germination, and reduce photosynthetic efficiency. Under low-temperature stress, cucumber plants typically incur damage to cellular membrane structures, experience an accumulation of reactive oxygen species (ROS), exhibit a disruption in hormonal homeostasis, and suffer from the inhibition of pivotal metabolic pathways. In response, cucumber plants activate an array of resistance mechanisms, encompassing osmotic adjustment, reinforcement of the antioxidant system, and modulation of cold-responsive gene expression. This review summarizes the physiological and molecular mechanisms underlying cucumber’s response to low-temperature stress, aiming to provide effective strategies for improving abiotic stress resistance. The main findings are as follows: (1) Low-temperature stress damages cucumber cell membranes, suppresses photosynthesis and respiration, suppresses water and nutrient uptake/transport, and suppresses growth retardation. (2) Cucumber counters these adverse effects by orchestrating the accumulation of osmoregulators (e.g., soluble sugars, proline), activating activation defenses (e.g., SOD, CAT), and rebalancing its phytohormone network (e.g., ABA, GA, SA, ethylene). (3) At the molecular level, cucumber activates low-temperature-responsive genes (e.g., COR, GoIS) through transcription factors such as CBF, MYB, and WRKY, thereby enhancing cold tolerance. (4) Application of exogenous protectants (e.g., hydrogen sulfide, melatonin, oligosaccharides) significantly improves cucumber’s low-temperature tolerance by modulating the antioxidant system, promoting osmoregulatory substances accumulation, and regulating hormone signaling pathways. Future research should focus on elucidating the molecular regulatory network in cucumber under low-temperature stress and developing gene editing with multi-omics techniques to advance the development of cold-resistant cultivars and cultivation practices. This study offers a scientific foundation for research on cucumber cold tolerance and proposes potential solutions to agricultural challenges in the context of global climate change. Full article

Drought limits plant growth, development and productivity, leading to more than 50% crop loss globally. Drought-induced oxidative stress disturbs the plant’s metabolism; however, plants activate signaling pathways to respond and adapt to drought stress. Although drought response mechanisms are well reported in several crops, these mechanisms are poorly understood in Amaranthus. As a highly nutritious crop, rich in antioxidants with the ability to survive in extreme agro-climatic environments, Amaranthus has the potential to serve as a climate-smart future crop. This review provides evidence of some drought response traits in grain and vegetable Amaranthus species. Grain amaranths are the most tolerant species, mainly through improved osmoregulation, antioxidant capacity, and gene expression. While biomass partitioning, efficient water use, and membrane stability have been reported in both grain and vegetable amaranth, the molecular response of vegetable amaranth remains limited. Thus, future research must focus on integrated biochemical, molecular, and multi-omics applications to screen and identify resilient Amaranthus genotypes under drought for sustainable agriculture. Full article

Drought stress is one of the primary abiotic factors negatively affecting garlic growth, development, and yield formation. The application of plant growth-promoting bacteria (PGPB) could enhance plant tolerance to drought stress. The aim of this study was to explore the regulatory effect of the PGPB Pseudomonas sp. UW4 on growth and physiological indexes of garlic under drought stress. The results revealed that drought stresses significantly reduced total root length, total root surface area, root projection area and total root volume, chlorophyll content, antioxidant enzyme activity and osmolyte content (proline and soluble proteins), and increased relative electrical conductivity and malondialdehyde (MDA) content, all of which could be significantly improved by inoculating the roots with strain UW4. Under drought stress, an increase in total surface area of roots of 87.06% and an increase in root projected area of 40.71% were observed upon inoculation with strain UW4. The a, b, and total content of chlorophyll were increased significantly by 83.63%, 217.33% and 100.02%, respectively. The osmolyte content in leaves significantly increased, and decreased significantly in roots. The content of antioxidants also significantly increased. Moreover, the relative electrical conductivity in leaves and roots was decreased by 23.18% and 41.20%, respectively, upon strain UW4 inoculation. The content of malondialdehyde (MDA) was decreased by 25.23% and 54.08%, respectively, in the presence of strain UW4. The result of principal component analysis (PCA) revealed that the key factors influencing drought tolerance in garlic inoculated with Pseudomonas sp. UW4 could be summarized into two categories: photosynthetic pigments and root growth-related factors, and leaf osmotic adjustment and root antioxidant enzyme-related factors. Based on the result of the Mantel test, it can be inferred that there was a connection between the osmoregulation and antioxidant enzyme systems in the roots and leaves. Based on the D values, the comprehensive evaluation result of drought resistance was that the drought resistance of the garlic inoculated with strain UW4 under drought stress was lower than that of the garlic inoculated with UW4 under normal treatment and higher than that of the garlic under normal treatment. Therefore, Pseudomonas sp. UW4 enhanced the drought resistance of garlic seedlings by improving root phenotype and antioxidant enzyme activity, and increasing the content of shoot chlorophyll. Full article

The physiological and gill health responses of juvenile spotted rose snapper (Lutjanus guttatus) were evaluated at four salinities—8, 16, 24, and 32‰—over a 70-day period. Fish reared at 8‰ exhibited the highest final body weight (126.8 ± 2.6 g), which was significantly higher than their congeners kept at 24‰ (116.0 ± 2.3 g) and 32‰ (116.0 ± 2.3 g). This superior growth at 8‰ coincides with the complete absence of parasitic monogenean infestations. In contrast, parasite prevalence increased with salinity, reaching 87.5% at 24‰, and was associated with gill pathologies like hyperplasia. Plasma osmolality and chloride levels decreased at lower salinities, while sodium and potassium levels showed a compensatory increase. Plasma cortisol and glucose levels remained stable across all treatments, indicating an absence of chronic stress. These findings suggest that the optimal rearing salinity for juvenile L. guttatus is near 8‰. The enhanced growth at this salinity appears to be the result of a net energy gain, stemming from a trade-off between the minor cost of osmoregulation in a hypo-osmotic environment and the major energetic benefit of avoiding parasitic disease. Full article

Salinity is a pivotal environmental factor that governs crustacean survival and development through its regulatory effects on key physiological processes, including osmoregulation and metabolic homeostasis. In the mud crab Scylla paramamosain, salinity tolerance of the megalopa plays an important role in larval survival rates and aquaculture yield. Here, we employed a combined transcriptomic and proteomic strategy to comprehensively dissect the molecular adaptive mechanisms of S. paramamosain megalopa exposed to acute and prolonged low-salinity stress (8‰) compared to control condition (17‰). Illumina-based transcriptome sequencing generated 81.71 Gb of high-quality clean data, which were assembled into 42,210 unigenes. LC-MS/MS-based proteomic profiling identified 51,390 unique peptides, corresponding to 5909 confidently quantified proteins. Transcriptomic profiling identified 2627 differentially expressed genes (DEGs) under acute low-salinity stress, comprising 1332 upregulated and 1295 downregulated genes compared to the control group. In contrast, a total of 733 DEGs were identified under prolonged low-salinity exposure, including 390 upregulated and 343 downregulated genes. Parallel proteomic analysis identified 199 differentially expressed proteins (DEPs) in the acute stress group, with 105 upregulated and 94 downregulated relative to the control group. Under prolonged stress, 206 DEPs were detected, including 124 upregulated and 82 downregulated proteins compared to the control group. Significant GO term and KEGG pathway enrichments contained metal ion binding, oxidoreductase activity, nucleus, apoptotic process, innate immune response, and amino acid metabolism, suggesting that megalopa employ coordinated regulatory mechanisms involving metabolic reprogramming, immunity system modulation, ion homeostasis maintenance and cell cycle regulation to adapt to hypoosmotic stress. Integrated multi-omics analysis identified 17 genes displaying significant concordant differential expression at both mRNA and protein levels during acute hypoosmotic stress, versus only 5 gene-protein pairs during prolonged stress exposure, indicating extensive post-transcriptional regulation and protein turnover mechanisms in sustained hypoosmotic condition. To the best of our knowledge, this study established the first integrative transcriptome-proteome framework elucidating hypoosmotic adaptation (8‰) mechanisms in S. paramamosain megalopa. The identified molecular signatures offer actionable targets for selective breeding of salinity-tolerant strains and precision management of megalopa culture under suboptimal salinity condition, while fundamentally advancing our mechanistic understanding of osmoregulatory plasticity across decapod crustaceans. Full article

Salinity, a critical environmental factor for fish survival, remains poorly understood in terms of how Triplophysa strauchii, a characteristic fish in Northwest China, physiologically responds to salinity stress. This study aimed to determine its salinity tolerance threshold and explore the associated physiological damage mechanisms. Six salinity gradients (11, 11.7, 12.5, 13.3, 14.3, 15.1 ppt) and a freshwater control group were established. Acute toxicity tests recorded mortality and behavior, while physiological–biochemical assays measured ion concentrations and enzyme activities in gills, kidneys, liver, intestines, and plasma over 96 h. The results showed a 96-hour median lethal concentration of 13.31 ppt and a safe concentration of 4.05 ppt. Gills and kidneys, as primary osmoregulatory organs, responded rapidly, whereas the liver and intestine lagged. Salinity ≤ 13.3 ppt allowed the fish to maintain homeostasis via physiological adjustments, but ≥14.3 ppt caused ion imbalance, immune function was significantly suppressed, and irreversible damage. These findings clarify the species’ salinity adaptation strategies, providing a basis for further research on chronic salinity stress. Full article

The anaerobic ammonium oxidation (anammox) process offers potential for saline wastewater treatment but is hindered by salt inhibition. This study investigates the salt tolerance mechanisms of granular (R1), biofilm-carrier (R2), and floccular (R3) sludge in up-flow anaerobic sludge blanket (UASB) reactors under 0–20 g/L NaCl. Granular sludge outperformed other biomass types, maintaining >90% ammonia nitrogen (${\mathrm{NH}}_4^{+}$-N) removal at 20 g/L NaCl due to structural stability and extracellular polymeric substances (EPS) adaptation (shift from hydrophobic proteins to polysaccharides). Microbial analysis revealed a transition from Planctomycetes/Proteobacteria to salt-tolerant Pseudomonadota, with Candidatus_Kuenenia replacing Candidatus_Brocadia as the dominant anaerobic ammonium oxidation bacteria (AnAOB) (reaching 14.5% abundance in R1). Genetic profiling demonstrated coordinated nitrogen metabolism: Hzs/Hdh inhibition (>85%) and NirBD/NrfAH activation (0.23%) elevated ${\mathrm{NH}}_4^{+}$-N, while NarGIV/NapA decline (1.10%→0.58%) increased nitrate nitrogen (${\mathrm{NO}}_3^{-}$-N). NxrB/NirSK maintained low nitrite nitrogen (${\mathrm{NO}}_2^{-}$-N), and GltBD upregulation (0.43%) enhanced osmoregulation. These findings underscore the superior resilience of granular sludge under high salinity, linked to microbial community shifts and metabolic adaptations. This study provides critical insights for optimizing anammox processes in saline environments, emphasizing the importance of biomass morphology and microbial ecology in mitigating salt inhibition. Full article

This study demonstrates that rearing duration (14 and 30 days) and environmental salinity (0, 4, 8, and 12 parts per thousand (ppt) of NaCl) synergistically modulate osmoregulation and muscle texture in adult freshwater drums (Aplodinotus grunniens). Salinity significantly reduced the hepatosomatic index at 30 days (p < 0.05). Furthermore, serum biochemical indices were markedly affected. Higher salinity and prolonged rearing time decreased triglycerides, total cholesterol, and low-density lipoprotein (LDL), while high-density lipoprotein (HDL) levels increased at 14 days (p < 0.05), indicating improved lipid metabolism efficiency. Crucially, osmotic pressure remained stable across salinities at 14 days but exhibited a dose-dependent increase at 30 days (p < 0.05), driven primarily by elevated Na⁺ and Cl⁻ concentrations. Salinity (8–12 ppt) markedly enhanced water-holding capacity, reducing cooking loss (~58%), centrifugal loss (~74%), drip loss (~83%), and thaw loss (~84%) versus 0 ppt controls (p < 0.05). Concurrently, key texture parameters also significantly improved, as reflected by hardness, chewiness, resilience, and gumminess. These enhancements might be attributed to hyperosmotic stress-induced cellular dehydration and ionic strength-mediated protein cross-linking. Full article

Environmental salinity is a critical factor influencing the physiological and metabolic processes of teleosts. Despite its importance, the molecular mechanisms underlying these responses, particularly those involving specific signaling pathways and gene expression regulation, remain poorly understood. To elucidate the role of lipid metabolism in osmotic regulation, the present study investigated the effects of varying salinity levels (2, 20, 40, and 60 ppt) on growth performance and metabolic status, including the biosynthesis of LC-FAs and VLC-FAs, respectively, in neural tissues (brain and eyes), of the euryhaline fish Fundulus heteroclitus over a 62-day period. The findings revealed multiple physiological adaptations to salinity variation, encompassing both molecular and metabolic responses. Salinity had a significant impact on growth performance, with fish exposed to the highest salinity level (60 ppt) exhibiting reduced growth. At this salinity, plasma levels of lipid-related metabolites, i.e., triglycerides and cholesterol, were decreased, whereas both osmolality and cortisol levels increased. Hepatic glucose and lactate levels increased with rising salinity, while glucose and triglyceride concentrations in muscle tissue declined. Additionally, intestinal lipase activity was significantly higher at 60 ppt. Although no significant differences were observed in the total UFAs content of both tissues, in the brain, significant differences were detected in the levels of 16:1n-7, 18:1n-9, 18:2n-6, 20:3n-3, 20:4n-6, and 20:5n-3, whereas in the eye, differences were observed only for 16:1n-7 and 20:5n-3. Gene expression analysis revealed that salinity exerts a regulatory effect on the expression of fads2b and elovl4a in the eye, with up-regulation observed at 60 ppt. In contrast, no significant changes in the expression of fads or elovl genes were detected in the brain. These findings highlight the contribution of non-osmoregulatory organs, such as the brain and eyes, in the osmotic adaptation of teleosts. Collectively, the results suggest that lipid metabolism plays a key regulatory role in the adaptation of F. heteroclitus to salinity fluctuations. Full article

Solute carrier family 12 (SLC12) encodes electroneutral cation-coupled chloride cotransporters responsible for transmembrane ion transport (Na⁺, K⁺, and Cl⁻), which play a critical role in aquatic osmoregulation. However, the SLC12 gene of Exopalaemon carinicauda (EcSLC12) has not been systematically identified or functionally characterized. In this study, six EcSLC12 genes were identified across the genome and classified into N(K)CC, KCC, CCC9, and CIP subfamilies. Three NKCC1 homologous genes (EcSLC12A2.1, EcSLC12A2.2, and EcSLC12A2.3) were reported for the first time in crustaceans. The EcSLC12 family exhibited distinct expression patterns in response to low-salinity, high-alkalinity, and saline–alkaline stress. EcSLC12A2.2 was highly expressed in the gill, and its expression was closely correlated with saline–alkaline acclimation. Additionally, EcSLC12A2.2 knockdown decreased E. carinicauda survival under saline–alkaline stress. Thus, EcSLC12A2.2 plays critical roles in osmotic regulation and saline–alkaline acclimation. This study provides crucial insights into E. carinicauda’s saline–alkaline tolerance mechanisms, and the discovery of multiple NKCC1 homologs fills a gap in the crustacean SLC12 gene family research. Full article

Nile tilapia (Oreochromis niloticus) is a key species due to its rapid growth, high nutritional value, and adaptability to diverse environments. However, changes in water salinity pose significant challenges to tilapia farming. Elucidating the adaptive strategies of tilapia to fluctuating salinity environments is crucial for improving aquaculture efficiency. This study investigated the transcriptional signature of growth-hormone-releasing hormone, somatostatin, growth hormone, and insulin-like growth factor (grhr-sst-gh-igf) axis in Nile tilapia under different salinity conditions (0 g/L, 16 g/L, and 30 g/L). The results showed that in brackish or seawater, Nile tilapia rapidly upregulate brain igfbp5 paralogues and their regulators (sst5, sstr2) to sustain growth-active IGF-1 signaling, while in the liver and gut, they downregulate sstr2b, igfbp1/7, and ghrh to reallocate energy toward osmoregulation. Physiological regulation, such as the use of ligand analogs, or genetic enhancement targeting these genes might hold promise for improving salt acclimation, which would enable profitable farming in brackish or coastal ponds and offer a simple tool for more resilient and efficient tilapia production. Full article

Freshwater ecosystems are increasingly stressed by drought and anthropogenic inputs that can increase specific conductivity (SPC) and pH; however, little is known about how harsher conditions affect fish. We evaluated how fish growth and diet composition changed along a natural gradient in SPC and pH in Wyoming, USA using Northern plains killifish (Fundulus kansae) and Fathead minnows (Pimephales promelas). We surveyed 201 sites where we measured water chemistry, sampled fish, and assessed invertebrate prey availability from May to September 2024. Northern plains killifish and/or Fathead minnows inhabited 12 sites, which were the focus of our study. We measured otoliths to assess growth and stomach contents to estimate dietary selectivity. Growth decreased at higher SPC (486–23,500 µS/cm) for Fathead minnows and pH (7.2–9.0) for both species, suggesting an energy trade-off with osmoregulation. Dietary analyses revealed variable selection for Chironomidae larvae, while other taxa such as Gammaridae and Coleoptera were avoided at higher SPC and pH. Despite the extreme conditions, these fish maintained some dietary preference, highlighting behavioral plasticity. Our findings suggest that while these species can tolerate harsh environments, sublethal effects on growth and diet may limit long-term fitness. This research offers a framework for assessing the viability of fish populations inhabiting ecosystems with increasing salinity and pH that can inform conservation and management strategies under future environmental change. Full article

In aquaculture, Pacific white shrimp (Litopenaeus vannamei) growth in low-salinity waters is limited by osmoregulatory stress; therefore, improving resistance to low-salinity stress via nutritional modulation is key. In the present study, shrimp postlarvae were provided with a taurine supplement under low-salinity stress, and then the survival rate, the histology, the Na⁺/K⁺-ATPase (NKA) expression pattern and transcriptomic sequencing were investigated to evaluate the postlarval responses. The results showed that the postlarva survival rate in low-salinity water was only 61.11%, which is significantly lower than that for postlarvae reared in saline water (92.67%). However, taurine supplementation significantly increased the postlarva survival rate in low-salinity culture to 76.67% and also increased the shrimp body length. Moreover, immunofluorescence and enzyme activity assays indicated that taurine alleviated NKA overactivation in the shrimp postlarvae under low-salinity stress. Furthermore, a GO enrichment analysis of differentially expressed genes suggested that the overactivation of hormone and receptor signaling under low-salinity stress was significantly downregulated after taurine supplementation. On the other hand, taurine supplementation may promote epithelial cell proliferation in shrimp postlarvae by negatively regulating the Wnt signaling pathway. These findings suggest that taurine may enhance the shrimp postlarval osmoregulatory capacity, thereby improving their ability to acclimatize to low-salinity environments. Full article

Staphylococcus shinii (S. shinii) is a coagulase-negative species primarily associated with the degradation of organic matter, contributing to nutrient cycling in natural environments. This species has been mainly studied in clinical and terrestrial contexts, with no previous reports of its presence in marine environments. In this study, we report the first isolation of S. shinii from a marine habitat. The strain SC-M1C was isolated from the Red Sea sponge Negombata magnifica. Whole-genome sequencing confirmed its taxonomic identity as S. shinii. The genome uncovers potential adaptive characteristics that facilitate survival in marine ecosystems, comprising genes associated with osmoregulation, nutrient acquisition, stress response, and resistance to heavy metals. Moreover, multiple genomic islands and plasmids were identified, suggesting a potential role in horizontal gene transfer and environmental adaptability. The presence of biosynthetic gene clusters linked to non-ribosomal peptides, siderophores, and terpene production indicates potential for biochemical versatility beyond traditional metabolic expectations. This study presents the first genomic insights into S. shinii in a marine context, highlighting its ecological significance and adaptive mechanisms in a high-salinity environment. These findings expand our understanding of staphylococcal ecology beyond terrestrial and clinical origins and provide a foundation for exploring the role of S. shinii in marine microbial interactions and environmental resilience. Full article