In natural soils, phosphorus predominantly exists in stable forms such as chelated inorganic phosphorus, resulting in low levels of available phosphorus. To cope with phosphorus limitation, woody plants typically form symbiotic associations with ectomycorrhizal fungi (ECMF) to enhance phosphorus acquisition. Studies have indicated that ECMF exhibit limited capacity to directly solubilize chelated inorganic phosphorus. However, they can recruit phosphate-solubilizing bacteria in the hyphosphere by releasing specific compounds, thereby facilitating the desorption of chelated inorganic phosphorus. Nevertheless, comprehensive reviews analyzing the role of plant-ECMF-bacteria tripartite systems in phosphorus cycling remain scarce. This article introduces the conceptual framework of plant-ECMF-bacteria tripartite systems, elucidates the physiological, biochemical, and molecular mechanisms underlying phosphorus cycling among ECMF, mycorrhiza helper bacteria, and host plants, and discusses future research directions for optimizing plant phosphorus acquisition through the tripartite systems.

[Objective] Aluminum (Al) toxicity in acidic soils severely inhibits plant growth by inducing oxidative stress. Ectomycorrhizal fungus (ECMF) can enhance host plant Al tolerance, but the underlying physiological mechanisms, particularly in fine roots, are not fully understood. This study investigates how ECMF colonization mitigates Al toxicity by modulating the antioxidant physiology of plants, with an aim in applying ECMF for the ecological restoration of Al-contaminated acidic soils. [Methods] Pinus massoniana seedlings were inoculated with Lactarius deliciosus 2 or Pisolithustinctorius 715, with non-ectomycorrhizal seedlings as the control. After a 6-month exposure to 0.0 mmol/L or 1.0 mmol/L Al³⁺, we assessed seedling biomass, fine root morphology, plasma membrane permeability, reactive oxygen species (ROS) levels, antioxidant enzyme activities, and osmoregulatory substance content. [Results] Under Al stress, inoculation with either L. deliciosus 2 or P. tinctorius 715 significantly promoted seedling growth and fine root development. The inoculated seedlings exhibited 1.26-1.33 folds greater biomass and 2.25-3.99 folds increases in the total root length, root surface area, root volume, and root tip number compared to the non-inoculated control. The ECMF inoculation also significantly reduced the accumulation of malondialdehyde (MDA), hydrogen peroxide (H₂O₂), proline, and soluble proteins in fine roots. Furthermore, inoculation with L. deliciosus 2 resulted in significantly higher root surface area and root volume, along with greater peroxidase (POD) and catalase (CAT) activities and a more pronounced reduction in proline content in fine roots, compared to inoculation with P. tinctorius 715. [Conclusion] Our findings demonstrate that ECMF inoculation alleviates Al stress in P. massoniana seedlings by promoting fine root development, bolstering the antioxidant system (notably through increased POD and CAT activities), reducing H₂O₂ accumulation, preserving plasma membrane integrity, and decreasing the synthesis of osmoregulatory substances. The superior performance of L. deliciosus 2 highlights its potential for its application in the ecological restoration of Al-contaminated acidic soils.

[Objective] We explored the nuclear translocation dynamics and pathways of the structural protein VP1 of Junonia coenia densovirus (JcDV) in the epidermal cell line HaEpi derived from the larvae of Helicoverpa armigera, aiming to provide theoretical support for clarifying the assembly and proliferation processes of JcDV. [Methods] The wild-type and mutant plasmids of VP1 protein fused with green fluorescent protein (GFP) were constructed and transfected into HaEpi cells. Subsequently, the subcellular localization dynamics of the VP1 protein were analyzed, and the nuclear localization signal (NLS) and key amino acid residues of the protein were identified. The importin genes expressed by HaEpi cells were cloned. Subsequently, the plasmids of importins fused with DsRed2 were constructed to analyze their subcellular localization. The co-localization and co-immunoprecipitation (Co-IP) assays were employed to analyze the interactions between VP1 protein and importins. [Results] The VP1 protein was located in the cytoplasm at 6 h post transfection, and then gradually translocated to the nucleus until 48 h. The NLS of VP1 protein was located at 325-EGTKRKADTPVEEGPSKKGAH-345, among which K328, R329, K341 were the key amino acid residues affecting the nuclear localization. The importins Haimpα1, Haimpα4, and Haimpα7 were located in the nucleus, while Haimpβ1 was mainly located around the nuclear membrane. The co-localization and Co-IP results indicated that the VP1 protein interacted with Haimpα1, Haimpα4, and Haimpβ1 but not with Haimpα7. [Conclusion] The structural protein VP1 of JcDV can be translocated into the nucleus through the dual pathways of importin α/β and importin β.

[Objective] This study examined the characteristics of the microbial communities and their associations with chemical components in aged tobacco leaves from different production areas in Yunnan Province, aiming to provide a theoretical foundation for the targeted exploitation of tobacco microbial resources and quality improvement of tobacco. [Methods] A systematic approach integrating metagenomic sequencing, GC/LC-MS, and Spearman’s correlation analysis was employed to investigate the microbial communities, chemical components, and their correlations of aged tobacco leaf samples collected from Dali, Wenshan, Honghe, Luoping, Pu’er, Zhaotong, and Lincang. [Results] The dominant bacterial phylum was Pseudomonadota in aged tobacco leaf samples. The dominant bacterial genera varied among different production areas. Specifically, Salinivibrio was identified as the core genus in the samples from Wenshan, while Methylobacterium and Sphingomonas exhibited significant enrichment in the samples from Luoping. For fungal communities, Ascomycota and Mucoromycota were the predominant phyla, and dominant fungal genera showed negligible variations. Alpha diversity analysis revealed the highest microbial richness and diversity in the samples from Lincang and the lowest in the samples from Wenshan. KEGG analysis revealed that metabolic pathways exhibited high relative abundance across samples from all regions, whereas environmental information processing pathways were more abundant in the samples from Wenshan. CAZy analysis showed that genes annotated as glycoside hydrolases (GHs) and glycosyl transferases (GTs) were the most prevalent, with both generally exhibiting lower abundance in the samples from Wenshan. Chemical profiling revealed that reducing sugar, total sugar and other conventional components were more concentrated in the samples from Dali, whereas total sugar-to-nicotine ratio and potassium-to-chloride ratio were elevated in the samples from Pu’er. Additionally, neutral aroma compounds, including benzyl alcohol, had significantly higher levels in the samples from Wenshan, while polyphenols such as anthocyanins exhibited markedly higher concentrations in the samples from Luoping. Correlation analysis further disclosed that Microbacterium had a significantly positive correlation with total nitrogen, while Aureobasidium showed a significantly negative correlation with total nitrogen. Leucosporidium exhibited significantly positive correlations with potassium ions and potassium-to-chloride ratio. Salinivibrio had significantly positive correlations with multiple neutral aroma components. In contrast, Methylobacterium and Friedmanniomyces showed significantly negative correlations with the majority of neutral aroma components. Additionally, Methylobacterium, Sphingomonas, Friedmanniomyces, and Metschnikowia had significantly positive correlations with multiple polyphenols. [Conclusion] Microbial communities and chemical components of aged tobacco leaves exhibited marked differences across different production areas in Yunnan. Notably, dominant genera are strongly correlated with aroma compounds, which lays a theoretical basis for targeted screening of functional microbes and the development of biotechnologies to improve tobacco quality.

Siderophores are low-molecular-weight, high-affinity iron-chelating molecules produced by bacteria in response to iron deficiency. Pseudomonas secrete siderophores to efficiently chelate insoluble Fe³⁺ in the environment, which is a crucial mechanism for their adaptation to iron-limited conditions. This article systematically reviews the types, structural characteristics, biosynthetic pathways (the non-ribosomal peptide synthetase,NRPS), and regulatory mechanisms of siderophores in Pseudomonas. Several regulatory factors at multiple levels were vitally elucidated, including Fur protein, σ factors, quorum sensing, and two-component system. Moreover, siderophores not only promote iron absorption in plants and bioremediation to remove pollutants but also are virulence factors in pathogen infection and factors in microbial spoilage. The siderophore-iron complex can be specifically recognized and actively taken up by bacteria, which is known as the “Trojan horse” mechanism, enabling covalently conjugated antibiotics to enter the cell and thus significantly boosting antibiotic efficacy. Future research should delve into the molecular regulatory networks and microbial interaction mechanisms to promote the application and development of siderophores in agriculture, medicine, and environmental protection.

The global prevalence of obesity and its associated metabolic disorders keeps rising, presenting a major challenge to public health. The gut microbiota plays a pivotal role in obesity onset and development, and its dysbiosis and dysfunction are closely associated with obesity and its complications. This review synthesizes the pathological mechanisms underlying the heredity, neuroendocrine, chronic inflammation, and the gut microbiota-metabolism axis of obesity. Then, we explore the positive and negative regulatory effects of opportunistic pathogens (e.g., Desulfovibrio spp., Megamonas spp.) and putative beneficial bacteria (e.g., Lactobacillus spp., Akkermansia muciniphila) on obesity. Furthermore, we summarize the mechanisms by which these signature gut microbes drive the development of obesity-related conditions, including type 2 diabetes mellitus, metabolic dysfunction-associated steatotic liver disease, cardiovascular diseases, and hypertension. We firstly propose a gut microbiota trajectory hypothesis to delineate the interrelationships between these representative gut microbial signatures and the onset and progression of obesity and its complications. Finally, the review discusses future research directions and the potential for developing early diagnostic technologies based on these microbial signatures. Collectively, this work aims to provide novel strategies for the early diagnosis and precision intervention of obesity and related metabolic disorders, thereby advancing the development of personalized therapeutics.

[Objective] Kiwifruit bacterial canker (KBC), caused by Pseudomonassyringae pv. actinidiae (Psa), has become the primary bottleneck restricting the sustainable development of the kiwifruit industry in China, highlighting an urgent need for eco-friendly and residue-free biocontrol strategies. [Methods] The kiwifruit variety ‘Hongyang’ was used to systematically evaluate the biocontrol efficacy of Bacillus pumilus H-46 through leaf disc and shoot inoculation assays. The active components were fractionated into three groups (small-molecule metabolites, proteins, and polysaccharides) via sequential extraction, with the major bioactive fraction identified through antimicrobial activity and disease control assessments. An integrated approach combining histochemical staining, antioxidant enzyme activity assays, and RT-qPCR of defense-related genes was employed to elucidate the mechanism of induced systemic resistance (ISR). Furthermore, pathogen migration and colonization assays were conducted to evaluate the inhibitory effects of the active components against Psa. [Results] B. pumilus H-46 showed excellent control effect against KBC, with the disease control efficacy of 86.54% in leaf disc assays. Its main active components (small-molecule metabolites, fraction A) achieved the control efficacy of 88.16% against KBC through non-antimicrobial mechanisms. The mechanisms included triggering early H₂O₂ accumulation and callose deposition, significantly increasing superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT) activities, and activating the expression of key genes (AcMYC2, AcAOC, AcERF2, and AcEIN3) in jasmonicacid (JA) and ethylene (ET) signaling pathways to activate ISR. Consequently, the disease resistance of kiwifruit was enhanced, resulting in a reduction of 37.8% in Psa migration distance in leaf veins and a decrease of 96.6% in colonization ability. [Conclusion] Our findings demonstrate that the small-molecule metabolites (fraction A) of B. pumilus H-46 activates JA/ET-mediated ISR via non-antimicrobial mechanisms, offering a sustainable solution for the control against KBC and establishing a prototype for next-generation plant immunity activators in crop protection.

The gut microbiota maintains a close dialogue with the host’s immune system, being capable of influencing immune responses through various pathways. It has been extensively documented that synchronous regulation of the gut microbiota and the host immune response exerts immunoenhancing, anti-inflammatory, and gut homeostasis-maintaining effects. By systematically reviewing the relevant literature published in the past three years, this article first elaborates on the interactions between the gut microbiota and the host’s immunity via multiple routes. It further summarizes recent studies on natural products that exert immunomodulatory functions (encompassing both immunoenhancing and anti-inflammatory actions) through gut microbiota pathways. Regarding immune dysregulation diseases, this review further elucidates how natural products achieve precise regulation of the host immune function by optimizing the gut microbiota structure, regulating microbiota-immune signaling pathways (e.g., NF-κB, TLR, and MAPK), maintaining intestinal barrier homeostasis, and intervening in microbiota-derived metabolites (such as short-chain fatty acids and tryptophan-indole derivatives). Additionally, this article discusses the process by which the gut microbiota enhances the immunomodulatory effects of natural products through metabolic conversion and biotransformation of natural products into highly active secondary metabolites. The immunoregulatory effects of natural products through the gut microbiota may become a potential therapeutic strategy for immune-related disorders.

[Objective] To study the phylogenetic relationship and genomic diversity of intestinal obligate commensal bacteria in different populations from various regions of Xinjiang and provide a theoretical basis for developing personalized functional probiotics for different populations. [Methods] A total of 136 strains of Bifidobacterium longum subsp. longum were isolated from mother-infant populations of Uygur and Kazak ethnic groups in Kashgar and Yili regions of Xinjiang. Comparative genomic analysis was conducted with data of the strains from other regions in China that were available in public databases. [Results] The average genome size, G+C content, and the number of coding sequences of B. longum subsp. longum were 2.38 Mb, 59.91%, and 2 160, respectively. The phylogenetic tree constructed based on core genes showed that all strains from Xinjiang belonged to four clades in the phylogenetic tree. Strains from the same ethnic group but from different geographical regions were in different clades, and there was a certain degree of overlap between geographically closer and different population-derived strains. The analysis of a larger geographical range (China) showed that B. longum subsp. longum strains and their functional genes presented obvious geographical and ethnic distribution characteristics. The analysis of COG functional genes and carbohydrate hydrolyase-related genes showed that the functional gene spectra varied greatly among strains from the same ethnic group but in different regions. The carbohydrate hydrolyase-related gene families GH13 (α-amylases) and GH43 (β-amylases) were more abundant in the strains from Kashgar region. Conversely, even strains from different ethnic groups but from geographically close regions had similar spectra of COG functional genes and carbohydrate hydrolyase-related gene families. [Conclusion] The B. longum subsp. longum strains and their functional genes from different geographical regions and ethnic groups in Xinjiang showed obvious geographical and ethnic distribution characteristics. As the geographical scale becomes large, the geographical distribution characteristics of the strains become more obvious. The relationship between the geographical distribution scale of populations and the co-evolution and specificity of strains should be verified based on larger-scale genomic data of strains.

Chloroquine, a low-cost antimalarial agent, has garnered significant interest due to its extensive research foundation and potential anti-tumor and antiviral properties. Chloroquine exhibits broad-spectrum inhibitory effects against diverse human and animal pathogenic viruses in vitro. Its antiviral efficacy has been demonstrated against Zika virus and feline coronavirus in vivo. The primary action mechanisms of chloroquine include inhibition of viral binding to host cells and subsequent internalization, modulation of viral nucleic acid recognition pathways, blockade of autophagosome maturation, and regulation of cytokine secretion in the immune response. This review systematically summarizes the antiviral effects and mechanisms of chloroquine, providing a theoretical foundation for the future development of chloroquine and its derivatives as antivirals.