Stress biology最新文献

Ferroptosis has been increasingly implicated in adipose and muscle dysfunction, systemic metabolic disturbances, and several diseases in livestock, which necessitates effective and side-effect-free inhibition strategies. Phloretin, a dihydrochalcone with excellent antioxidant and anti-inflammatory properties, may have the potential to restrain cell ferroptosis. Herein, phloretin was verified to significantly inhibit (1S,3R)-RSL3-induced ferroptosis by reducing intracellular MDA, Fe²⁺, and ROS levels and restoring cell total antioxidant capacity in bovine and mouse preadipocytes or myoblasts. It also alleviated oxidative stress (OS), a vital inducer of ferroptosis, by restoring antioxidant enzyme activity in the above cells and obese mice. In vivo, phloretin gavage significantly reversed the trend where high-fat diet (HFD)-induced OS promoted the expression of ferroptosis-promoting genes and proteins (e.g., ACSL4 and PTGS2) while inhibiting the expression of ferroptosis-negative regulators (e.g., Fth1 and Gpx4). Unlike most flavonoids that exert anti-inflammatory or antioxidant activities by altering the gut microbiota composition, metagenomic sequencing analysis of cecal contents from phloretin-gavaged and HFD mice revealed that phloretin exerts its antioxidative and ferroptosis-inhibitory effects independent of modulating gut microbiota diversity. Further transcriptomic analyses of mouse adipose tissues revealed that phloretin alleviated ferroptosis in adipocytes by modulating the transcription of genes enriched in AMPK and PPAR signaling pathways, such as Camkk2. Hence, based on multi-omics analysis combined with in vivo and in vitro verification, phloretin effectively alleviated the OS to further inhibit ferroptosis of adipose or muscle cells through the AMPK-PPAR pathway, which can provide new research ideas for ameliorating adipose or myocyte dysfunction induced by ferroptosis in animals.

Phytophthora pathogens are devastating agricultural threats that cannot synthesize sterols and must scavenge them from host plants. This study exploits their sterol auxotrophy by engineering a dual-function elicitin protein, SOJ5^V84F, for enhanced disease control. The V84F mutation in the sterol-binding pocket of the Phytophthora sojae elicitin SOJ5 abolishes sterol binding but retains interaction with the pathogen's sterol-sensing receptor kinase SSRK1. SOJ5^V84F acts as a dominant-negative inhibitor: it competitively disrupts SSRK1-mediated sterol signaling (calcium influx, MAPK activation) and significantly inhibits P. sojae growth in an SSRK1-dependent manner. Crucially, SOJ5^V84F retains its ability as a microbe-associated molecular pattern to robustly elicit reactive oxygen species burst in soybean, pepper, tomato, and potato plants. Consequently, pre-treatment with SOJ5^V84F provided superior protection compared to wild-type SOJ5 against P. sojae in soybean, and against Phytophthora capsici and Phytophthora infestans in pepper, tomato, and potato under greenhouse conditions. This work demonstrates that engineered SOJ5^V84F combines direct pathogen inhibition with host immune activation, establishing a novel dual-mechanism strategy for protein-based biocontrol against sterol-auxotrophic oomycetes.

Drought, high salinity, and low temperatures impose osmotic stress, hindering water uptake and severely limiting plant growth and crop productivity. Osmotic stress not only perturbs cellular osmotic homeostasis but also disrupts multiple metabolic processes, including reactive oxygen species (ROS) metabolism. However, the transcriptional regulation underlying these redox processes in plants remains poorly understood. Here, we report that rice NAC WITH TRANS-MEMBRANE MOTIF1- LIKE 2 (OsNTL2) is required for tolerance to salt and osmotic stresses. DNA affinity purification-sequencing (DAP-seq) revealed that OsNTL2 directly targets key genes in the ascorbate-glutathione (ASC-GSH) redox cycle, including ascorbate peroxidase 2 (APX2), monodehydroascorbate reductase 1 (MDHAR1), glutathione reductase 2 (GR2), and glutathione peroxidase 5 (GPX5), as well as peroxidase 3/70 (PRX3/70), which function in the hydrogen peroxide catabolic process. Consistently, OsNTL2 activity was associated with enhanced ASC-GSH cycle enzyme activities, elevated ASC and GSH contents, and reduced ROS accumulation, as confirmed by histochemical staining. Furthermore, integrating DAP-seq with transcriptome analysis, we identified 325 direct transcriptional targets of OsNTL2, with a significant enrichment of genes involved in lignin and xylan biosynthesis. Notably, OsNTL2 bound directly to the promoters of, 4-coumarate-CoA ligase 5 (Os4CL5), and cinnamoyl-CoA reductase (OsCCR), activating their transcription. Correspondingly, stress-induced lignin, xylan, and cellulose accumulation was markedly reduced in ntl2 mutants but enhanced in OsNTL2-overexpressing lines. Together, these findings identify OsNTL2 as a key transcriptional regulator that coordinates the ASC-GSH redox cycle and cell wall biosynthesis to confer osmotic stress tolerance in rice.

The occurrence of apple replant disease (ARD) is closely related to the increase of soil pathogenic fungi abundance. However, the relationship between ARD and fungal community structure remains poorly understood. In this study, Illumina high-throughput sequencing was used to investigate the composition, diversity, and function of rhizosphere fungal communities associated with healthy (HRS) and diseased apple trees (DRS). Microbial taxa related to ARD were also identified. The severity of ARD varied among the sampled orchards. We found that Ascomycota was the dominant phylum in the DRS fungal taxa, and the fungal community abundance and Simpson index of DRS were significantly higher than those of HRS. Cluster and FUNGuild database analyses revealed significant differences in the relative abundance and function of fungal taxa between DRS and HRS. Most fungi isolated from DRS were plant pathogens, predominantly from the genus Fusarium (Ascomycota, Nectriaceae), which was also the predominant fungal genus detected in DRS. In contrast, Mortierella was more abundant in HRS. To validate the sequencing results, Fusarium isolates, including F. proliferatum, F. oxysporum, and F. solani, were verified as pathogens and showed high virulence. Structural equation modeling indicated that the occurrence of ARD was directly or indirectly influenced by Fusarium, Mortierella, phloridin, available phosphorus, and soil organic matter. Further research is needed to elucidate how soil parameters affect ARD. Laboratory tests demonstrated that F. proliferatum MR5 can produce pectinase and cellulase and is sensitive to two fungicides: flusilazole and bromothalonil. In conclusion, the deterioration of rhizosphere fungal community structure may be a key biological factor driving ARD, with Fusarium in DRS identified as a major causative agent of ARD in China. The findings of this study provide valuable insights for developing preventive strategies against ARD.

To elucidate the molecular mechanisms by which choline regulates hepatic lipid metabolism under negative energy balance conditions, we established non-esterified fatty acid (NEFA)-induced hepatic steatosis models in both calf primary hepatocytes and human LO2 hepatocytes. Choline supplementation significantly reduced intracellular triglyceride accumulation and cytotoxicity induced by NEFA exposure. Transcriptomic profiling identified glycine N-methyltransferase (GNMT) as a key differentially expressed gene. Subsequent experiments confirmed that choline upregulated GNMT expression at both the mRNA and protein levels in a concentration-dependent manner. Knockdown of GNMT reversed the beneficial effects of choline on genes related to lipid synthesis (FAS, ACC), fatty acid oxidation (CPT1), lipoprotein assembly (ApoB100, MTTP), and bile acid metabolism (CYP7A1, CYP27A1, BSEP). Furthermore, inhibition of AMP-activated protein kinase (AMPK) reduced GNMT protein expression and elevated Myc, a negative transcriptional regulator of GNMT, suggesting that choline may regulate GNMT through the AMPK/Myc axis. Collectively, our findings demonstrate that choline alleviates NEFA-induced lipid accumulation and hepatocellular damage by modulating lipid and bile acid metabolism through GNMT, with the AMPK/Myc/GNMT signaling axis playing a pivotal regulatory role. These results provide mechanistic insights into the hepatic protective effects of choline and suggest GNMT as a potential therapeutic target for metabolic disorders in dairy cows and beyond.

Mosses play a crucial role in environmental protection, ecological preservation, and horticulture. While the effects of nanomaterials on angiosperms have been widely studied, their impact on bryophytes remains underexplored. In this study, we investigated the effects of mesoporous silica nanoparticles (MSNs) and virus-like mesoporous silica nanoparticles (VMSNs) on the model moss species Physcomitrium patens (P. patens). Our results revealed that MSNs, with an average size of approximately 123 nm, are nontoxic to P. patens and enhance its salt tolerance. The expression of key genes involved in stress responses were significantly induced in MSN-treated plants under salt stress, including peroxidase (POX), L-ascorbate oxidase (L-AO), alternative oxidase (AOX), and calcium-dependent protein kinase (CPK). MSN treatment reduced the accumulation of H₂O₂ and O₂^·-, increased Ca²⁺ signaling, and modulated reactive oxygen species (ROS) homeostasis, collectively improving moss tolerance to salt stress. MSNs were observed on the cell surface, in intercellular space, and within the cytosol and vesicles. They were transported bidirectionally between rhizoids and apical leaves. This study provides novel insights into the distribution, transport, and functional mechanisms of MSNs in mosses, offering a valuable foundation for the application of nanomaterials in plant stress biology and ecological management of bryophytes.

Desert plants have evolved remarkable adaptations to survive in arid environments, where water scarcity and extreme temperatures pose significant challenges to life. The desert moss Syntrichia caninervis stands out as an exemplary model of extreme desiccation tolerance (DT), offering invaluable insights into plant adaptation to water deficit. This study presents a comprehensive multi-omics analysis of S. caninervis during controlled dehydration and rehydration process, integrating transcriptomic, proteomic, and metabolomic data to elucidate the molecular mechanisms underlying its remarkable resilience. Our findings reveal a sophisticated, multilayered response characterized by extensive transcriptional reprogramming (3,153 differentially expressed genes), dynamic proteome remodeling (873 differentially expressed proteins), and strategic metabolic reconfiguration (185 differentially abundant metabolites). Key adaptations include the coordinated downregulation of photosynthetic processes, upregulation of stress-responsive genes and proteins, accumulation of protective metabolites, and enhancement of antioxidant systems. Notably, we observed significant temporal asynchrony between transcript and protein levels, underscoring the complexity of post-transcriptional regulation in stress responses. The core mechanisms of S. caninervis DT comprises cellular protection and metabolic dormancy during dehydration, followed by efficient repair and recovery processes upon rehydration. These findings not only advance our understanding of plant evolution and adaptation to extreme environments but also identify potential targets for enhancing drought tolerance in crops and exploring plant survival under extreme environment. By deciphering the molecular basis of extreme DT, this research opens new avenues for addressing agricultural challenges in water-limited environments and expands our knowledge of plant life's adaptability to harsh terrestrial.

Clothianidin, a widely used neonicotinoid pesticide, poses potential ecological risks to aquatic ecosystems due to its unique mode of action and widespread environmental dispersal. This study investigates the toxic effects of clothianidin on Penaeus vannamei at different concentrations over 28 days. High concentrations of clothianidin significantly affected shrimp physiology, as evidenced by changes in survival rate and weight gain. Markers of oxidative stress, including decreased respiratory burst, reduced glutathione levels, and diminished antioxidant enzyme activities, indicated that clothianidin triggered oxidative stress responses in shrimp. Additionally, changes in lactate dehydrogenase, succinate dehydrogenase, and isocitrate dehydrogenase activities suggested disruptions in energy metabolism in the hepatopancreas. Analysis of the nervous system revealed significant disturbances in neural signaling, reflected by altered levels of acetylcholine, acetylcholinesterase, and dopamine. Transcriptomic analysis highlighted significant changes in gene expression and metabolic processes in the nervous system. This study demonstrates that clothianidin disrupts oxidative balance, energy metabolism, and neural signaling, affecting the growth of P. vannamei and providing valuable insights into its biochemical and transcriptomic toxicity in aquatic environments.

Plants are continuously exposed to environmental abiotic and biotic stressors that can significantly impact their growth, development, productivity, and lifespan. However, plants have developed exceptionally complex signaling pathways that enable their ability to sense, transduce, and respond to these diverse stress stimuli. Salicylates (SA) and jasmonates (JA) are two key phytohormones that significantly influence plant adaptation to environmental and biotic stressors, pivotal in enhancing stress resilience. The interaction and crosstalk between SA and JA signaling cascades are essential for orchestrating appropriate physiological and biochemical responses to biotic (e.g., pathogen attack, herbivory) and abiotic (e.g., oxidative stress, drought, temperature extremes, UV radiation, salinity, heavy metal toxicity) stresses. Salicylates are primarily recognized for being involved in systemic acquired resistance (SAR) against biotic stressors like pathogens. Conversely, jasmonates are well-documented in their function in defenses aimed at herbivorous insects and in mitigating the outcomes of abiotic conditions such as salinity and drought. However, the crosstalk between SAs and JAs is complex, involving both synergistic and antagonistic interactions that finely tune the natural defensive mechanism of the plant toward both biotic and abiotic stresses. This comprehensive review summarizes the most recent research on how SA and JA biosynthesis, signaling, and interactions govern diverse stress adaptive mechanisms in plants. It covers emerging evidence on the importance of SA-JA crosstalk in regulating physiological, biochemical, and molecular adaptations to combined biotic and abiotic stresses.

Exosomes as bilayer membranous vesicles are abundant in seminal plasma and mediate intercellular communication by transferring active biomolecules. Numerous studies have revealed the involvement of exosomes in regulating various biological properties of spermatozoa. However, the beneficial roles of seminal plasma exosomes in maintaining spermatozoon motility and mitochondrial function during liquid storage have not yet been unexplored in goat. In this study, the reduction of ATP content in goat spermatozoa was detected along with the decrease in spermatozoon motility under liquid storage, and the level of oxidative phosphorylation was also decreased. The interaction of exosomes and spermatozoon mitochondria was observed using high pressure freezing/freeze-substitution in combination with transmission electron microscope. Seminal plasma exosomes of goat were isolated and used to incubate with spermatozoa, and the binding and fusing of exosomes with spermatozoa was further validated. Furthermore, the addition of seminal plasma exosomes exhibited an increase in motility and oxidative phosphorylation in liquid-stored spermatozoa. Several mitochondrial functional parameters, including mitochondrial membrane potential, the levels of mitochondrial ROS and intracellular Ca²⁺, and the copy number and integrity of mitochondrial DNA, were also improved in spermatozoa after incubating with exosomes. Notably, the level of TFAM protein was increased in exosome-treated spermatozoa, indicating that the enhanced proteins may be delivered by exosomes to spermatozoa. These results suggest that seminal plasma exosomes could improve spermatozoon motility and mitochondrial function by regulating oxidative phosphorylation, which would provide insights into the understanding of protective roles of exosomes in goat spermatozoa during liquid storage.