As the core saccharification agent in traditional Chinese brewing processes, Daqu plays an irreplaceable role in Baijiu production due to its complex microbial community and multifunctional enzyme system. This review begins by outlining the application scenarios and characteristics of saccharification agents in both Eastern and Western brewing industries. Subsequently, based on the research of microbiology, genomics, proteomics, etc., this review elaborates on the diversity of microorganisms and enzymes with saccharifying function in Daqu, along with the roles of Daqu in saccharification. Finally, strategic approaches are proposed, including utilizing multi-omics technologies to elucidate the functional mechanisms of Daqu during brewing and enhancing the integration of mechanism research with industrial practice, which may provide references for the innovative development of saccharification agents in the brewing industry.

Phosphorus is an essential nutrient element for plant growth and development. However, the available phosphorus in soil is extremely limited due to the presence of large amounts of organic phosphorus that is difficult to be degraded, with phytate (inositol hexaphosphate) accounting for a significant proportion. Phytases can efficiently hydrolyze phytate and release available phosphorus. [Objective] By taking advantage of the efficient hydrolysis ability of phytase, the phytase gene was gene modified in the indigenous bacteria of black soil to increase the available phosphorus content in the soil. [Methods] We employed the anchored protein pGSA for surface display of the bacterial phytaseAppA, thereby enhancing the stability and enzymatic activity of the protein as well as improving the substrate contact efficiency. Furthermore, leveraging the CRISPR-targeted gene editing technology, we precisely integrated the surface-displayed phytase fusion protein into the 16S rRNA gene of Ralstonia pickettii G3 genome, isolated from black soil to overcome the dependence of protein expression on vectors. [Results] The 16S rRNA gene site could be used as a target for gene modification without significant effect on the proliferation of the bacteria. The phytase-modified engineered bacteria showed a more than 8-fold increase in the hydrolytic ability of phytate and functioned in a wide pH range. After this indigenous engineered bacterial strain was applied to black soil, the soil phytase activity significantly increased, and the available phosphorus content rose by nearly 30%. [Conclusion] Modifying phytase by gene editing can promote the hydrolysis of phytate, increase the content of available phosphorus, and improve the phosphorus availability in the soil.

[Objective] To design and express a recombinant protein rMKIBV incorporating confirmed antigenic epitopes of infectious bronchitis virus (IBV) as a vaccine to provide comprehensive protection. Additionally, it explores the potential of polyclonal yolk antibodies (IgY) harvested from laying hens immunized with the rMKIBV vaccine in the prevention and control of IBV. [Methods] The antigenic epitope sequences of IBV, obtained from online databases, were compared with sequences of representative IBV strains from GenBank. Flexible peptides were designed to link all antigenic peptides. The constructed amino acid sequence was analyzed, reverse-translated, codon-optimized, and then inserted into the pET-28a(+) cloning vector. The recombinant vector was introduced into Escherichia coli for expression. The purified, desalted, and endotoxin-removed rMKIBV protein was used as a vaccine to immunize animals for investigation of its immunogenicity and ability to stimulate specific IgY production in laying hens. [Results] The retrieved IBV antigenic epitope sequences showed high similarity with the published N and S protein sequences of 22 representative IBV strains. The predicted isoelectric point and molecular weight of rMKIBV were 10.25 and 63.39 kDa, respectively. The secondary structure of rMKIBV included a high proportion of random coils, which suggested strong antigenicity. High-purity rMKIBV was obtained from E. coli transformed with the recombinant plasmid pET-28a-mkibv. This protein specifically bound to anti-His-tag antibodies, N protein antibodies, and S protein antibodies. The mice immunized with this protein showed increases in the spleen index (P<0.05), elevations in the levels of serum-specific IgG antibodies (P<0.01) and IFN-γ (P<0.05), and no significant change in the IL-2 level. Immunized laying hens successfully produced IgY in egg yolks, with specific IgY antibody levels significantly increasing. Moreover, the IgY antibody titer gradually rose after immunization, reaching the peak after about 50 days and then gradually declining to reach a stable level. [Conclusion] We successfully constructed and expressed the recombinant protein rMKIBV. The protein demonstrated good immunogenicity, stimulating specific antibody production in both mice and laying hens. Notably, the IgY extracted from the yolks of immunized laying hens offers a novel approach to IBV prevention and control. These findings hold significant scientific and practical value for the development of vaccines against IBV.

Root-knot nematodes(Meloidogyne spp.) are widely distributed and highly destructive, causing substantial economic losses in agricultural production. Biocontrol has been considered as an effective measure for managing these pathogens. [Objective] To explore efficient and eco-friendly biocontrol resources for controlling root-knot nematodes. [Methods] Bacillus strains were isolated from soil via the serial dilution method. Strains with strong nematicidal activity against Meloidogyne incognita second-stage juveniles (J2) were screened by in vitro bioassays. The selected strains were identified based on morphological, physiological, and biochemical characteristics, as well as molecular biological evidence. The biocontrol potential of these strains was further evaluated by egg hatching inhibition assays, phosphorus/potassium solubilization tests, enzymatic activity profiling, and antagonistic spectrum analysis. Additionally, pot and greenhouse experiments were conducted to validate the biocontrol efficacy of strains. [Results] Among 189 bacterial strains isolated from 16 soil samples, strains Sneb2550 and Sneb2556 demonstrated strong nematicidal activity against M. incognita J2, inducing the corrected mortality rates of 95.64% and 95.36%, respectively, after 24 h. Based on morphological features, physiological and biochemical characteristics, and 16S rRNA gene and gyrB sequences, strains Sneb2550 and Sneb2556 were identified as Bacillus proteolyticus and B. amyloliquefaciens, respectively. Functional characterization showed that strain Sneb2550 produced protease and inhibited Fusarium asiaticum, Trichothecium roseum,and Alternaria solani. Strain Sneb2556 produced protease and amylase, solubilized phosphate, and suppressed F. asiaticum, Aternaria alternata, Botryosphaeria dothidea, T. roseum, Colletotrichum gloeosporioides, and A. solani. Moreover, both strains did not adversely affect cucumber seed germination and significantly promoted the radicle growth. Under pot conditions, Bacillus Sneb2550 and Sneb2556 significantly reduced root galls formation, with the reduction rates of 56.02% and 50.19%, respectively, while promoting plant growth. Field experiments showed that root irrigation with Bacillus Sneb2550 and Sneb2556 effectively controlled cucumber root-knot nematodes, with the control effects of 60.90% and 52.63%, respectively, while promoting plant growth. [Conclusion] Bacillus Sneb2550 and Sneb2556 effectively controlled cucumber root-knot nematodes and promoted plant growth, providing new potential resources for the biocontrol of root-knot nematodes.

Nitrogen fertilizer is an important chemical fertilizer for agricultural planting and an important fertility factor for increasing crop yields. Lack or excess of nitrogen fertilizer in soil will lead to soil acidification, soil consolidation, low crop yields and so on. Nitrogen-fixing bacteria can reduce nitrogen in the air to ammonia that is beneficial to crops through the action of nitrogenase. This process helps improve soil quality and subsequently promote crop growth. [Objective] To obtain nitrogen-fixing bacteria from the black soil of northeast China and explore the effects of nitrogen-fixing bacteria on soil quality and maize growth, thus providing excellent strain sources for the development of microbial agents suitable for the environment of black soil in northeast China. [Methods] We employed microbial isolation, culture, and functional characterization to measure the nitrogen fixation, phosphorus solubilization, and indole-3-acetic acid (IAA) secretion of the screened nitrogen-fixing bacteria. Pot experiments and soil physical and chemical tests were carried out to evaluate the effects of nitrogen-fixing bacteria on soil quality and maize growth. [Results] Three strains of nitrogen-fixing bacteria were obtained from the black soil of northeast China. Among them, Paenibacillus sp. AHC-20 had higher nitrogen-fixing ability, while Raoultella sp. Z93 and Paraburkholderia sp. W22 were multifunctional strains capable of fixing nitrogen, solubilizing phosphorus, and producing IAA at the same time. The three nitrogen-fixing strains were then applied to the black soil planted with maize. The plant height, biomass, and chlorophyll content of maize significantly increased in the chemical fertilizer reduction+AHC-20 group compared with those in the control group with application of only chemical fertilizer. In addition, the content of inorganic carbon, organic carbon, organic matter, ammonium nitrogen, and nitrate nitrogen in black soil also increased significantly, which indicated that the efficient nitrogen-fixing bacterial strain AHC-20 promoted maize growth upon chemical fertilizer reduction and improved the fertility of black soil. [Conclusion] Nitrogen-fixing bacteria in black soil can effectively promote the growth of maize and improve the quality of black soil to achieve fertilizer reduction without compromising crop yields, showing the potential for the development of nitrogen-fixing microbial agents.

[Objective] Seed endophytes are key components of the plant microbiome, and their community structure and diversity are highly susceptible to environmental changes. Revealing the effects of fencing versus grazing management on the endophytic microbial communities of Caragana korshinskii seeds is essential for elucidating the dynamic interactions among plants, soil, and microorganisms. This study also provides a theoretical foundation for ecological restoration in arid and semi-arid grasslands. [Methods] The study was conducted in Otog Front Banner, Inner Mongolia, focusing on C. korshinskii under two management practices: fencing and grazing. The physicochemical properties of soil were analyzed by high-throughput sequencing of seed endophytic microbial communities to assess shifts in their structural composition and diversity under these contrasting regimes. [Results] Fencing management decreased soil pH while increasing moisture content, total carbon, total nitrogen, and total phosphorus of soil. Grazing management increased the abundance-based coverage estimator (ACE) index of seed endophytic fungi. Fencing increased the relative abundance of Pseudomonadota and decreased the relative abundance of Bacillota in seed endophytic bacteria, while promoting the relative abundance of Pantoea. In seed endophytic fungi community, Alternaria dominated under fencing management, while Trichoderma dominated under grazing management. Additionally, grazing management increased the number of modules and complexity in seed endophytic bacterial-fungal networks. [Conclusion] The contrasting management practices of fencing and grazing in desert stepps alters soil environment, thereby shaping the diversity and community structure of both bacterial and fungal endophytes in C. korshinskii seeds. This study reveals the impact of different management measures on plant-microbe interactions in desert steppes, providing theoretical support for related research.

Streptococcus suis is a major pathogen in pigs and also a zoonotic pathogen. This bacterium has numerous serotypes, among which S. suis serotype 4 (SS4) is known to infect humans and poses a threat to public health due to its potential high pathogenicity. [Objective] To develop a multiplex PCR method based on specific virulence-associated genes of SS4 virulent strains to achieve precise identification of such strains. [Methods] Based on previous research results, four target genes specific to SS4 virulent strains—sly, igdE, tran, and sao—were selected, and the SS4 serotype-specific gene wzy was used as an internal reference gene to design a pentaplex PCR method. After optimization of the multiplex PCR amplification system, specificity and sensitivity tests were conducted. This method was then employed to detect newly isolated SS4 strains. Additionally, zebrafish virulence assays were performed to validate the accuracy of this method. [Results] The multiplex PCR method specifically amplified the target genes, effectively distinguishing SS4 virulent strains from lowly virulent strains. The method exhibited high sensitivity, with a minimum detection limit of 4.1×10² CFU or 12.5 pg of genomic DNA. Specificity validation confirmed that this method accurately identified SS4 virulent strains. This method was then employed to examine six clinically isolated SS4 strains. Three strains were identified as virulent, showing high pathogenicity in zebrafish and causing a mortality rate of 60.00%-86.67%. The other three strains were identified as lowly virulent strains, exhibiting low pathogenicity in zebrafish and causing a mortality rate of 0-6.67%. [Conclusion] A multiplex PCR method based on virulence-associated genes of S. suis was successfully developed, enabling accurate and sensitive identification of SS4 virulent strains. This method provides technical support for the early diagnosis and effective prevention and control of S. suis infections.

One Health integrates the health of the environment, animals, and humans, involving food safety, environmental hygiene, and animal and human health. Currently, antibiotic resistance is exacerbating worldwide, seriously hindering the achievement of One Health. Phages, as viruses with a century-long application history and the ability to specifically kill bacteria, bring new hope for addressing antibiotic-resistant bacterial infections. This article reviews the development history, diversity, and applications of phages in food safety and the environment, animals, and humans, with the aim of providing references for the application of phages in the era of One Health.

[Objective] To investigate the structural characteristics of microbial consortia in different concentrations of petroleum hydrocarbons, cultivate efficient petroleum hydrocarbon-degrading microbial consortia, and mine the strain resources capable of degrading petroleum hydrocarbons. [Methods] We used 0# diesel as the sole carbon source to domesticate oil-contaminated soil samples through five successive generations by gradually increasing the 0# diesel concentration. The structural changes of microbial consortia were uncovered by 16S rRNA gene amplicon sequencing. The strains with petroleum hydrocarbon-degrading potential were isolated and purified via dilution plating and streaking. Finally, the improved 2,6-dichlorophenol indophenol (DCPIP) cultivation system was employed to identify efficient degrading strains. [Results] During domestication, when the concentration of 0# diesel was raised to 7 000 mg/L, the relative abundance of petroleum hydrocarbon-degrading bacteria including Bacteroidota and Bacillota significantly increased. A total of 58 bacterial strains belonging to 25 genera, 22 families of 4 phyla were isolated, including 31 (53.45%) strains of Pseudomonadota, 13 (22.41%) strains of Actinomycetota, 11 (18.97%) strains of Bacillota, and 3 (5.17%) strains of Bacteroidota. From the isolated strains, 18 petroleum hydrocarbon-degrading strains were screened out. [Conclusion] Through gradient domestication, seven natural microbial consortia were successfully enriched, achieving over 70% degradation of petroleum hydrocarbons at 7 000 mg/L of 0# diesel. Amplicon sequencing revealed that varying 0# diesel concentrations altered the microbial consortium structure. Additionally, 18 strains capable of using 0# diesel as the sole carbon source were identified, providing potential microbial resources for the bioremediation of oil-contaminated soil.

[Objective] Black soil regions are globally critical for grain production, with their soil health directly impacting world food security and ecological stability. These regions hold significant strategic importance for sustainable agriculture and human health. In recent years, rapid advancements in microbiome research methodologies have highlighted the pivotal role of soil microorganisms in the sustainable utilization and health management of black soil. [Methods] To systematically summarize the research status and trends in black soil microorganisms, we employed “bibliometrix” R package and VOSviewer to conduct bibliometric analysis. We quantitatively analyzed the literature from the Web of Science core collection (2014-2024) and manually screened the abstracts. [Results] The results revealed a surge in the research on black soil microorganisms after 2021, with China, Russia, and the United States being the most prolific contributors. Leading institutions included the Chinese Academy of Sciences, University of Chinese Academy of Sciences, Northeast Agricultural University, Heilongjiang Academy of Agricultural Sciences, and Chinese Academy of Agricultural Sciences. Key findings were predominantly published in Applied Soil Ecology, Soil Biology & Biochemistry, and Eurasian Soil Science. Current research focuses on microbial networks, biochar applications, and rhizosphere microecology, emphasizing the roles of microorganisms in soil fertility regulation, environmental remediation, soil improvement, climate change responses, and farming system optimization. Studies also explore interactions between microorganisms and environmental factors such as soil aggregates, physicochemical properties, and enzyme activities, with a growing shift toward mechanism insights. [Conclusion] Over the past decade, research on black soil microbiota has rapidly advanced, with current focus on the role of microorganisms in soil fertility enhancement and sustainable utilization. Future studies should integrate cutting-edge technologies such as microbiomics, metagenomics, metatranscriptomics, and metabolomics to comprehensively analyze microbial community distribution, functionality, and regulatory mechanisms. Ultimately, this will provide a robust theoretical and technical foundation for the sustainable use and health enhancement of black soil resources.