Irritable bowel syndrome (IBS) is a functional gastrointestinal disorder characterized by abdominal pain, abdominal distension, and abnormal bowel movements. Its pathogenesis involves multiple factors such as imbalance of gut microbiota, immune activation, and dysfunction of the gut-brain axis. Although conventional therapies can alleviate symptoms temporarily, the limitations such as drug side effects and insufficient efficacy persistence have made microbial-targeted therapy a research hotspot. Probiotics are live microorganisms and have been proven to be beneficial to human health. Studies have shown that probiotics inhibit pathogen adhesion through competitive colonization, regulate immune responses, and repair the intestinal barrier function through metabolic products, thereby improving intestinal motility and osmotic balance. This review discusses the specific effects and potential pathways of probiotics on constipation, diarrhea, abdominal pain and distension, and mental symptoms in IBS patients. However, the clinical application of probiotics still faces challenges, including strain heterogeneity, host individual differences, and the lack of standardized treatment plans. In the future, it is necessary to combine multi-omics technologies to screen biomarkers, develop individualized intervention strategies, and optimize efficacy through dynamic monitoring, which are expected to provide more precise microbial-targeted therapy for the treatment of IBS.

[Objective] To explore the control effects of Streptomyces TOR3209 and its volatile organic compounds (VOCs) on tomato Fusarium wilt and mine the differentially expressed genes related to disease resistance, thus providing effective strategies for the development of environmentally friendly biofungicides. [Methods] Strain TOR3209 suspensions of different concentrations (1.0×10¹, 1.0×10³, 1.0×10⁵, and 1.0×10⁷ CFU/mL) were co-cultured with tomato seedlings, and Fusarium equiseti was inoculated on the seedlings. The disease severity was graded. The co-culture experiment of VOCs from strain TOR3209 with tomato seedlings was conducted in a micro-greenhouse to evaluate the effect of VOCs on tomato seedlings infected by F. equiseti. Transcriptomic analysis was conducted on tomato seedlings with significant disease resistance to mine the differentially expressed genes induced by VOCs, which were then verified by RT-qPCR. [Results] The suspensions of strain TOR3209 at different concentrations all had control effects on tomato Fusarium wilt. Among them, the 1.0×10⁷ CFU/mL suspension had the best control effect (P<0.01). The biocontrol effects of different quantities of small dishes cultured with strain TOR3209 on tomato Fusarium wilt were significantly different from that of the control group. The group of 30 small dishes showed the best control effect (P<0.01). The transcriptomic analysis showed that the expression levels of disease-resistance genes encoding CXE17, LRR-RLK, F-box, TIP1-1 Aquaporin, and Peroxidase were upregulated. Fluorescence quantitative analysis indicated that co-culture of VOCs from the strain with tomato seedlings upregulated the expression levels of disease-resistance genes, indicating that the transcriptomic sequencing results were reliable. [Conclusion] The VOCs of strain TOR3209 effectively prevent and control tomato Fusarium wilt caused by F. equiseti infection by inducing the upregulated expression of disease-resistance genes in tomato seedlings. The findings lay a theoretical foundation for the research and development of biofungicides for the prevention and control of Fusarium wilt.

[Objective] To explore the structural differences and associated environmental factors of bacterial communities in the water and sediment of river ecosystems during winter. [Methods] Fourteen sampling sites were established for Diannong River in winter. We employed high-throughput 16S rRNA gene sequencing to systematically analyze the bacterial community composition and diversity, constructed co-occurrence networks, and evaluated the roles of random processes in community assembly. Furthermore, we performed correlation analysis with environmental factors. [Results] The bacterial communities in the sediment had higher alpha diversity indexes than those in the water (P<0.001) and more stable community structures. The beta diversity decomposition showed that the community differences between water and sediment were mainly related to species turnover. Random processes dominated community assembly in both habitats. The co-occurrence network of bacteria in the sediment was more complex with stronger cooperation. Key species were primarily involved in carbon and sulfur cycles, and rare taxa played an important role in network stability. The bacterial communities in water were mainly influenced by environmental factors such as dissolved oxygen, chlorophyll a, and water temperature, while those in the sediment were influenced by pH, organic matter, and nitrogen factors. [Conclusion] This study systematically reveals the differences in the structure, co-occurrence network, and related environmental factors of bacterial communities in the water and sediment of Diannong River during winter, providing scientific evidence for a deeper understanding of the ecological adaptability of river bacterial communities in the freezing period and the different patterns of bacterial communities between water and sediment.

[Objective] To unravel the mechanism underlying the high-yield performance of hybrid pepper (Capsicum annuum L.) progenies and dissect parent-progeny differences across four interconnected dimensions: plant nutrient accumulation, rhizosphere soil physicochemical properties, microbial community composition, and nutrient metabolism-related functional genes. [Methods] For both parental lines and their hybrid progenies, the yields and the content of nitrogen (N), phosphorus (P), and potassium (K) in roots, fruits, and rhizosphere soil were determined, alongside rhizosphere soil physicochemical properties. High-throughput sequencing was adopted to analyze the structures of root endophytic and rhizosphere microbial communities, while metagenomic sequencing was used to quantify the abundance differences of genes associated with rhizosphere nutrient metabolism. [Results] Hybrid progenies exhibited a significant yield increase, with the highest yield increase observed in the Z3 line. All hybrids showed elevated K content in fruits, and Z3 specifically achieved transgressive accumulation of N and P in roots. A distinct turnover of the root endophytic microbial community was detected between parents and progenies. In the hybrids, functional genera including Dyella, Burkholderia-Caballeronia-Paraburkholderia, and Trichoderma were enriched, which were significantly correlated with plant nutrient uptake. In terms of rhizosphere soil properties, all hybrids had higher available phosphorus content and lower rhizosphere pH than parental lines. Notably, Z3 possessed unique advantages of high total nitrogen reserve and increased organic matter content in the rhizosphere. Additionally, the abundance of genes related to P and K metabolism was higher in hybrids than in parents, which was particularly prominent in Z3. [Conclusion] The transgressive yields of pepper hybrids is driven by the synergy among the rhizosphere environment, microbial communities, and the host plant. Specifically, hybrid progenies constructed an efficient microecosystem by enriching functional microbes (e.g., Dyella) and enhanced nutrient metabolism efficiency through increased abundance of P and K metabolism-related genes. These improvements ultimately led to the formation of nutrient utilization advantages, characterized by efficient nutrient absorption in roots and effective nutrient translocation to fruits. This study provides a novel theoretical framework for deciphering the microbial-driven mechanisms underlying parent-progeny differences in nutrient use efficiency of crops and further enriches the theory of plant-microbe-soil interactions.

Chitin is the second largest renewable resource only after cellulose on Earth. Chitinases are the key enzymes for degrading chitin. Chitinases of the glycoside hydrolase family 19 (GH19) mainly exist in higher plants. In recent years, microbial GH19 chitinases have been widely discovered. This paper reviews the research progress in microbial GH19 chitinases regarding their distribution, structures, enzymatic properties, and applications and prospects the research directions in the future.

[Objective] To investigate the biocontrol potential of Penicillium sinense GS218, a new endophytic fungus, and to analyze the antifungal mechanism, so as to provide elite strain resources and lay a theoretical foundation for the biocontrol of Colletotrichum gloeosporioides in pepper. [Methods] Plate assays were employed to determine the hydrolase activity and siderophore production capacity of GS218. The inhibitory effects of GS218 on different phytopathogenic fungi were evaluated by the plate confrontation method. Whole genome sequencing was performed to obtain insights into the genetic information and physiological functions of the strain. The metabolome of strain GS218 co-cultured with C. gloeosporioides was analyzed to explore the potential active substances for the inhibitory effects. The medicated plate method was employed to validate the inhibitory activities of differential metabolites. [Results] Strain GS218 had hydrolase activity, produced siderophores, and exhibited strong inhibitory effects on five pathogenic fungi (with the inhibition rate of 72.76% on C. gloeosporioides in pepper). The sterile fermentation filtrate of strain GS218 demonstrated a good control effect on pepper anthracnose. The genome size of strain GS218 was 27.77 Mb, which has abundant metabolic pathways, and its genome contained 30 synthetic gene clusters for secondary metabolites. The metabolomics analysis showed that strain GS218 contained rich antimicrobial substances in organic acids and derivatives, phenylpropanoids and polyketides, and lipids and lipid-like molecules (including terpenoids). Compounds such as 7-ethoxycoumarin and pyruvic acid showed inhibitory effects against C. gloeosporioides in pepper. [Conclusion] The new strain, P. sinense GS218, has significant inhibitory effects on C. gloeosporioides and promising application prospects in the green development of agriculture. Whole genome sequencing and metabolomics analysis provide a theoretical basis for deciphering the biocontrol mechanism of strain GS218.

[Objective] To analyze the evolutionary conservation and structural characteristics of the heat shock protein GrpE from Mycoplasma bovis, elucidate its subcellular localization, and investigate its biological properties in mediating the adhesion process. [Methods] Primers were designed based on the GrpE gene sequence (GenBank accession number: CP002188.1) of Mycoplasma bovis PG45, and the prokaryotic expression vector pET-GrpE was constructed. Following gene sequencing, bioinformatics methods were employed to analyze the homology, phylogenetic relationships, physicochemical properties, and structural characteristics of GrpE. Following transformation of the recombinant plasmid and induced expression, the yielded recombinant GrpE protein was purified via nickel affinity chromatography, and then SDS-PAGE was conducted. The purified recombinant protein was used to immunize New Zealand White rabbits to generate polyclonal antibodies, with the antibody titer determined by ELISA and immunogenicity assessed via Western blotting. The subcellular localization of GrpE was examined via indirect indirect fluorescent antibody assay (IFA), ELISA, and Western blotting. The adhesion function of GrpE was validated through integrated IFA and ELISA. [Results] The prokaryotic expression vector pET-GrpE was successfully constructed in this study. Bioinformatics analysis revealed that the GrpE sequence was highly conserved in Mycoplasma bovis (with identity exceeding 95%). The encoded protein consisted of 341 amino acid residues, with no signal peptide and transmembrane domain but potential N-glycosylation and phosphorylation sites. SDS-PAGE results confirmed the successful expression of GrpE in a soluble form. Polyclonal antibodies generated via the purified recombinant protein exhibited a titer of 1:16 000. Western blotting analysis further verified the strong immunogenicity of the GrpE protein. Localization studies using IFA, ELISA, and Western blotting indicated that GrpE is distributed in both the cell membrane and the cytoplasm, with predominant distribution observed on the membrane surface. Importantly, the anti-GrpE polyclonal antiserum significantly inhibited the adhesion of Mycoplasma bovis to embryonic bovine lung (EBL) cells. Furthermore, binding assays demonstrated that the interaction between GrpE and host cell membrane proteins is dose-dependent, and this binding was inhibited by the polyclonal antibody (P<0.001). [Conclusion] GrpE is identified as a highly conserved novel adhesion of Mycoplasma bovis that directly participates in the adhesion to host cells, providing a key molecular target for elucidating the pathogenic mechanism of Mycoplasma bovis.

[Objective] Human parainfluenza virus type 3 (HPIV-3) is a key factor in global acquired respiratory infections, and there is no specific therapy available. Due to the complexity and variability of the pathogen antigen, the development of vaccines against HPIV-3 is lagging behind. It is crucial to design a novel broad-spectrum vaccine for comprehensive protection against continuously mutated wild-type strains. [Methods] To overcome the antigenic variation of the virus, we downloaded different HPIV-3 antigen proteins (F, M, N, and HN proteins) from NCBI and generated consensus sequences through sequence alignment. Furthermore, a broad-spectrum T cell epitope vaccine targeting HPIV-3 was predicted and designed via methods of reverse vaccinology. [Results] The multi-epitope vaccine (MEV) incorporated 11 cytotoxic T lymphocyte (CTL) epitopes (9-mer) and 11 helper T lymphocyte (HTL) epitopes (15-mer) from the F, M, N and HN proteins, being composed of 355 amino acid residues without adjuvant. The predicted T cell epitopes had solubility, no allergenicity, high antigenicity, and immunogenicity. The designed vaccine can effectively bind to Toll-like receptors in natural immunity, with good stability, hydrophilicity, and high population coverage. [Conclusion] The designed vaccine could be a candidate vaccine against HPIV-3 infection. We provide a novel immunoinformatics approach for vaccine design and development.

Antibodies serve as critical effector molecules in mediating vaccine-induced protection. While antibody-mediated immunity has traditionally been attributed primarily to neutralization, where the fragment antigen-binding (Fab) domain blocks viral entry by preventing the interaction between viruses and host cells, accumulating evidence underscores the pivotal role of the crystallizable fragment (Fc) domain in orchestrating broader immune responses. By interacting with Fc receptors or complement receptors on effector cells such as natural killer cells, macrophages, neutrophils, and dendritic cells, the Fc domain activates multiple innate immune pathways and elicits a spectrum of non-neutralizing antiviral effector functions. These include antibody-dependent cellular cytotoxicity (ADCC), antibody-dependent cellular phagocytosis (ADCP), antibody-dependent complement deposition (ADCD), and complement-dependent cytotoxicity (CDC). Although the evaluation of Fc-mediated functions is more complex than the measurement of neutralizing antibody titers, the contribution of such functions to vaccine efficacy is increasingly recognized. This review provides a comprehensive overview of Fc-mediated immune effector mechanisms, highlights their critical roles in antiviral vaccine-induced protection, and summarizes recent advances in Fc function assays, with the aim of supporting the rational design and immunogenicity evaluation of next-generation viral vaccines.

The mandarin fish (Siniperca chuatsi) is one of the most economically important cultured fish species in Asian countries. With the expansion of artificial farming, infectious diseases have become a major threat to the mandarin fish farming industry, posing a challenge to its sustainable development. Siniperca chuatsi rhabdovirus (SCRV) is a major pathogen infecting this fish species. In recent years, substantial progress has been made in the research on SCRV, yet no comprehensive review is currently available. This paper summarizes and discusses the research advances in SCRV, including viral characteristics, virus rescue, host-virus interactions, and prevention strategies, while also analyzing the current challenges in this field.