The α-herpesviruses are a large class of enveloped double-stranded DNA viruses characterized by neurotropic infection and latent infection, posing a serious threat to human and animal health. The α-herpesvirus genome encodes a variety of proteins.UL24, a major virulence gene of α-herpesviruses, encodes a highly conserved protein and play a key role in regulating viral infection. This paper introduced the basic characteristics ofUL24 and the encoded protein and summarized the regulatory roles of UL24 in the virus assembly, replication, infection, pathogenicity, and inhibition of host innate immunity, aiming to provide a theoretical reference for understanding the functions of α-herpesvirus proteins and further preventing and controlling α-herpesvirus infection.

[Objective] This study aims to improve the bactericidal ability of phages against carbapenem-resistantKlebsiella pneumoniae, a major pathogen in clinical practice, and reduce host resistance to phages by developing a novel method of phage training.[Methods] Phages were isolated from municipal wastewater by the double-layer agar plate method with clinical carbapenem-resistantK.pneumoniae strain Kp2092 as the host, and their host ranges were analyzed. The morphological and genetic characteristics of a phage strain with strong lysis ability and a broad host range were analyzed by transmission electron microscopy and whole-genome sequencing. Phage training was performed by phage-host co-culture for generations, and the phages before and after training were compared in terms of biological properties such as bactericidal activity, optimal multiplicity of infection, one-step growth curve, and stability under different stress conditions.[Results] A total of 9 phage strains were isolated, in which P55anc was a short-tailed phage with the strongest lysis ability and the broadest host range. The genome (40 301 bp) of P55anc included 51 coding sequences, of which 27 showed possible functions involving nucleic acid metabolism, virion morphogenesis, DNA packaging, and host lysis. Three evolved phages of P55anc were obtained after 9 days of phage training. These evolved phages showed significantly enhanced bactericidal activities, manifested by the increased burst size, broadened host range, and reduced host resistance. Moreover, the evolved phages maintained stable when being exposed to heat, ultraviolet, and serum treatments.[Conclusion] Phage training by phage-host co-culture can be employed to obtain evolved phages with enhanced bactericidal effects. Furthermore, the evolved phages reduced the host resistance and remained stable under different stress conditions.

[Objective] To investigateBacillus velezensis XRD006 in terms of the inhibitory effects on diseases of postharvest green walnuts, the fresh-keeping effect on green walnuts, genetic characteristics, secondary metabolites, and antifungal mechanism.[Methods] The activities of XRD006 against pathogens of postharvest green walnuts were determined by the inhibition experiments.In vivo fungal inhibition and storage quality experiments were conducted to investigate the inhibitory effects of the strain on pathogens and the effect of the strain on the storage quality of postharvest green walnuts. The genomic characteristics and potential antifungal genes of XRD006 were investigated by whole genome sequencing. The secondary metabolites of XRD006 were predicted by antiSMASH, and the collinearity and differences of the secondary metabolite gene clusters between strains XRD006, FZB42, and SQR9 were analyzed by comparative genomics. The secondary metabolites of XRD006 were identified by high performance liquid chromatography (HPLC) and mass spectrometry. The antagonistic ability of the strain was tested by the oxford cup method.[Results] The inhibition rates of XRD006 againstColletotrichum aenigma,Colletotrichum siamense,Botryosphaeria dothidea, andFusarium fujikuroi of postharvest green walnuts were 49.22%, 50.61%, 53.83%, and 58.71%, respectively.In vivo antifungal experiments showed that XRD006 effectively inhibited the infection and growth of pathogenic fungi on the fruits. The fermentation supernatant of XRD006 significantly retarded the weight loss, inhibited the microbial growth, and reduced changes in peroxidase (POD) and polyphenol oxidase (PPO) activities while maintaining the kernel quality. The whole genome sequencing showed that the genome of XRD006 was 4 371 975 bp in length, containing 46.07% GC and 4 362 protein-coding genes (including antifungal and plant growth-promoting genes such as extracellular hydrolase and biofilm genes). The antiSMASH predicted that XRD006 had nine known and five unknown gene clusters of secondary metabolites. XRD006 was closely related to FZB42 and SQR9, and they shared eight secondary metabolite gene clusters, which showed varied location and coding genes. XRD006 produced two families of lipopeptides: iturin and fengycin. Compared with C13-iturin, C14-iturin, C15-iturin, and C17-fengycin C, C16-fengycin B of the fengycin family had the strongest inhibitory effect onC.siamense HT12.[Conclusion] B.velezensis XRD006 has good biocontrol effects on diseases of postharvest green walnuts and the potential for application in production.

Inhibiting the synthesis of fungal cell wall is a safe and effective strategy for preventing and treating fungal infections. Chitin synthases are the key enzymes to catalyze the synthesis of chitin, an important structural component of fungal cell wall and septa. The roles of chitin synthases vary in regulating the synthesis of fungal chitin. This review outlines the roles of chitin synthases in regulating fungal cell proliferation, morphogenesis, interactions with hosts, and compensatory effect induced by cell wall damage in the three major pathogenic fungal species:Candida albicans,Aspergillus fumigatus, andCryptococcus neoformans, aiming to understand the importance of chitin synthases in fungal pathogenicity. Furthermore, this paper proposes a new antifungal strategy and the future research directions about the chitin synthases of fungi.

[Objective] To screen out a fungal strain that can efficiently assimilate ammonia nitrogen, reveal the metabolome differences of the strain in different media and the changes in the amino acid content of the feed fermented with the strain, and clarify the mechanism of its ammonia assimilation.[Methods] Seven strains ofTrichoderma, 7 strains ofAspergillus niger, and 9 strains ofAspergillus oryzae were cultured in the media with (NH₄)₂SO₄ as the only nitrogen source. The strains with high ammonia nitrogen use efficiency and glutamine synthetase (GS) activity were selected for comparison of the metabolic differences in potato dextrose agar (PDA) plates and inorganic nitrogen plates by non-targeted metabonomics. Furthermore, the crude protein and organic nitrogen content in the feed fermented with different strains was determined, and the changes in amino acid content in the fermented feed extract were measured by amino acid-targeted metabolomics.[Results] The utilization rate of ammonia nitrogen and the glutamine synthetase activity ofA. oryzae MQ28 were 54.46% and 0.61 μmol/(h·g), respectively, which were higher than those of other strains (P < 0.05). The comparative metabonomics analysis suggested that MQ28 was associated with the metabolism of multiple amino acids during ammonia assimilation. MQ28 fermentation increased the crude protein and organic nitrogen in the feed by 22.25% and 35.83% (P < 0.05), respectively. Furthermore, MQ28 fermentation increased the total amino acid content in feed extract from 31.86 mmol/100 g to 57.69 mmol/100 g (P < 0.05). Specifically, it increased the content of 14 amino acids such as threonine, lysine, and arginine, glutamic acid (by 3.46 folds), and glutamine (by 99 folds) (P < 0.05).[Conclusion] To sum up,A.oryzae MQ28 has high ammonia nitrogen utilization capacity. It may regulate the ammonia assimilation process through the synthesis of glutamine to regulate amino acid metabolism and can be used as an elite strain for the production of single-cell protein.

[Objective] To mitigate the threat of heavy metal pollution in wastewater to global food safety and human health, reduce the accumulation of lead (Pb) in soil, plants, and animals, and improve the removal rate of heavy metals by immobilizing microbial strains.[Methods] We carried out mixed strain test to select the white rot fungal strains with strong Pb²⁺ removal effects and excellent compatibility and explored the optimal strains and ratio for combination. Furthermore, we optimized the formula of the fungal strain composite and explored the optimal adsorption conditions of the composite in application.[Results] Phanerochaete chrysosporium,Coriolus versicolor,Lentinus sajor-caju, andPleurotus ostreatus with good compatibility were selected for subsequent experiments.C.versicolor mixed withL.sajor-caju at a volume ratio of 1:1 outperformed the single strains in removing Pb²⁺. The fungal strain composite composed of 20.0 g/L sodium alginate, 15.0 g/L biochar, 2.0×10⁶ CFU/mL white rot fungi, silica, and zeolite showed the Pb²⁺ removal rate of 90.63% within 96 h. Moreover, this composite had higher mechanical strength and strong resistance to mechanical shear. At the addition amount of 8.35 g/L and pH 5.64, the composite demonstrated the Pb²⁺ removal rate of 97.45% within 96 h. Moreover, this composite can be reused 7 times after adsorption-desorption-readsorption and maintained high Pb²⁺ removal capacity.[Conclusion] The immobilized white rot fungal strain composite can significantly improve the microbial utilization rate and wastewater treatment efficiency compared with single strains. It can greatly adsorb Pb²⁺ in wastewater under appropriate conditions within a short time and reduce the environmental threat caused by heavy metal pollutants. Therefore, the promotion of environmental protection greatly benefits from the use of immobilized mixed white rot fungal strains in the treatment of heavy metal-contaminated wastewater.

[Objective] Bacillus velezensis SH-1471 (CCTCC No. M 2022923, Patent No. ZL 2022 1 1479280.X) is a strain that can control soil-borne diseases of crops and promote soil nutrient conversion and crop growth. This study aims to explore its potential biological activity and the optimum fermentation conditions, so as to promote the industrialization and commercial development of this strain.[Methods] A strain SH-1471 was identified based on the morphological, physiological, and biochemical characteristics and the 16S rRNA gene andgyrB-based phylogenetic trees. PCR was carried out to detect antibiotic synthesis genes in the strain. The inhibitory spectrum of the strain was measured by the plate confrontation assay and the fermentation liquid inhibition test. The abilities of the strain to produce enzymes, solubilize phosphorus and potassium, fix nitrogen, and secrete siderophoresin vitro were measured. The fermentation conditions were optimized by single factor tests and response surface methodology withOD₆₀₀ value and inhibition rate as indicators. The growth-promoting effect of the fermentation liquid on tomato plants and the control effect of the fermentation liquid on tomatoFusarium wilt before and after optimization were determined by indoor pot experiments.[Results] Strain SH-1471 was identified asB.velezensis, carrying the antibiotic synthesis genessrfA,fenB,ituA,ituD, andbymA. It had strong antagonistic effects on 8 pathogenic microorganisms such asFusarium oxysporum,Alternaria alternate, andExserohilum turcicum. Moreover, the strain was capable of producing protease and cellulase, solubilizing phosphorus, fixing nitrogen, and secreting siderophores. The optimal medium formula for the fermentation of SH-1471 was composed of 17.92 g/L sucrose, 16.95 g/L soybean powder, 2.88 g/L magnesium sulfate, and 5.0 g/L yeast extract. The optimum fermentation conditions were pH 7.5, 33 ℃, 220 r/min, and 20–24 h. After optimization, the inhibition rate,OD₆₀₀, and potted control efficiency of the fermentation liquid reached 94.08% (increasing by 15.6%), 3.28 (increasing by 36.7%), and 93.8%, respectively. Moreover, strain SH-1471 significantly improved plant height, stem circumference, root length, root weight, and fresh weight and dry weight of the aboveground part of tomato seedlings.[Conclusion] B.velezensis SH-1471 carries rich genes for antibiotic synthesis, has the abilities of producing protease and cellulase, solubilizing phosphorus, fixing nitrogen, and secreting siderophores, and demonstrates strong inhibitory effects on a variety of pathogens. It can significantly reduce the incidence of tomatoFusarium wilt and improve the agronomic traits of tomato seedlings. Therefore, the strain has broad application prospects in the biocontrol of plant diseases and the promotion of plant growth.

[Objective] To explore the reasons for differences in the C-methylation programming of non-reducing polyketide synthases (NR-Pkss).[Methods] We used bioinformatics tools and AlphaFold 2 to compare the domain sequences and structures of the NR-Pkss involved in the synthesis ofMonascus pigment and citrinin inMonascus ruber M7, i.e., Mr-PksPT and Mr-PksCT. Furthermore, we employed molecular docking to compare the binding of C-methyltransferase domains (CMeTs) with other domains and the intermediates of the two NR-Pkss.[Results] The large differences of the overall structure and the high similarity of domain sequence and structure between the two NR-Pkss suggested that the differences of C-methylation programming between NR-Pkss may be resulted from domain interactions. The CMeT of Mr-PksCT was more likely to bind to the acyl carrier protein (ACP) carrying the substrate than that of Mr-PksPT, making the intermediate more easily catalyzed by CMeT. Moreover, CMeT had lower binding free energy to methyl receptor substrate than theβ-ketosynthase domain (KS).[Conclusion] The CMeTs of NR-Pkss can affect the C-methylation of the products by competing with KS. The findings provide a new idea for the study of C-methylation programming of Pkss.

The term "microorganism" refers to tiny organisms such as archaea, bacteria, protists, fungi, and viruses, and the term "microbiome" refers to a collection of microorganisms. Although they share the body space of the host, their roles as determinants in host health and diseases are ignored. As a collection of information, the microbiome includes the genomic data, structural elements, metabolites, and environmental conditions of microorganisms. Studies have demonstrated that the microbiome plays an essential role in maintaining host homeostasis and regulating host phenotypes. With the advent of new technologies, including next-generation sequencing (NGS) and sequencing-based microbiome profiling, researchers have probed into the relationship between the microbiome and host phenotypes. By an overview of microbiome, this paper elaborated on the microbiome-host genetics interactions based on genome-wide association analysis and made an outlook on the future of this field.

Retinoid acid-inducible gene-I-like receptor (RLR) signaling pathways, the immune signaling pathways in response to infections, play a regulatory role in the production of pro-inflammatory cytokines, chemokines, and type Ⅰ interferons. Ubiquitination as one of the post-translational modifications refers to the process of ubiquitin binding to different amino acid sites on the target proteins, which regulates the fates of proteins. For example, it initiates the proteasome pathway to degrade the target protein or activating the protein transport. The ubiquitination of RLR signaling pathways is a way of regulating multiple effectors and one of the classical pathways through which viruses induce major diseases in animals, autoimmune diseases, and chronic inflammation. This paper introduces the typical structural features and the ubiquitination types of key effectors in the RLR signaling pathways. Furthermore, it expounds the roles of ubiquitination in the regulation of key molecules in the RLR signaling pathways, aiming to provide a reference for the intervention or treatment of related diseases.