Fruiting bodies represent pivotal resources with medicinal and edible values, hosting a diverse array of microbes. Although studies have elucidated the composition and structures of bacterial communities inhabiting fruiting bodies, the diversity and biological functions of fruiting body-associated microbes remains elusive. The symbiotic associations between fruiting bodies and their microbial inhabitants play integral roles in promoting the growth, enhancing the adaptation to environmental stresses, and facilitating the accumulation of secondary metabolites of host fungi. Additionally, these fruiting body-associated microbes exhibit promising biomedical properties, including antibacterial, antioxidant, and anti-tumor activities. This paper reviews the recent advancements in the isolation and cultivation techniques of these associated microbes, delineates the diversity of associated bacteria, actinomycetes, and fungi, elucidates their biological activities, and provide insights into the intricate interactions between associated microbes and their host fungi. This review offers avenues for the future research and utilization of fruiting body-associated microbes.

[Objective] To optimize the anaerobic digestion process for methane production of hulless barley straw with mixed addition of biochar and Fe₃O₄ and investigate the feasibility of mixed addition of biochar and Fe₃O₄ in the anaerobic digestion of lignocellulosic waste. [Methods] We employed single factor and response surface experiments to optimize the anaerobic digestion process for methane production of hulless barley straw with mixed addition of biochar and Fe₃O₄. Metagenomics was employed to analyze the microbial community structure and methane production pathway during digestion. [Results] The optimal digestion conditions were 6.32% total solids, biochar-to-Fe₃O₄ ratio of 6.83:3.17, and inoculation ratio (volatile solids ratio of inoculum to hulless barley straw) of 2.51. Under these conditions, the measured value of cumulative methane production based on volatile solids was 269.04 mL/g, with a relative error of less than 5% from the predicted value (265.95 mL/g), which indicated that the model was effective. The mixed addition treatment under the optimized conditions increased the methane production of hulless barley straw (P<0.05), with the effect comparable to that of the chemical pre-treatment. Meanwhile, the treatment increased the acetic acid content while reducing the accumulation of propionic and butyric acids. Metagenomic analysis showed increases in the relative abundance of bacterial taxa such as unclassified_Bacteroidota, unclassified_Bacteria, Clostridium, and Fibrobacter, as well as acetotrophic methanogens such as Methanosarcina and Methanothrix, which promoted the utilization of acetic acid and enhanced the direct interspecies electron transfer (DIET) between microorganisms. The mixed addition of biochar and Fe₃O₄ in the anaerobic digestion system enhanced the acetotrophic methanogenic pathway, thereby enhancing methane production. [Conclusion] The response surface methodology can optimize the anaerobic digestion process for methane production of hulless barley straw with mixed addition of biochar and Fe₃O₄. The mixed addition of biochar and Fe₃O₄ enables efficient production of biomethane and environmentally friendly treatment of lignocellulosic waste.

Tomato bacterial wilt caused by Ralstonia solanacearum seriously affects the yield and quality of tomato and brings serious economic losses and challenges to the tomato planting industry. [Objective] To achieve efficient biocontrol of tomato bacterial wilt by Streptomyces, providing a solid theoretical foundation for the development of biocontrol agents. [Methods] Six biocontrol strains of actinomyces (AB_1 to AB_6) exhibiting potent inhibitory activities against R. solanacearum were isolated from soil samples. The morphological, physiological, biochemical, and taxonomical characteristics of these strains were determined. Additionally, the extracellular enzyme activities and rhizosphere colonization abilities of the strains were analyzed. Furthermore, a greenhouse pot experiment was conducted to evaluate the biocontrol efficacy of these strains against tomato bacterial wilt. [Results] The inhibitory zone diameters of the strains against R. solanacearum ranged from 1.76 cm to 6.76 cm. Comparative analysis of the 16S rRNA gene sequences revealed that all the six strains belonged to the Streptomyces. The sequence similarities between strain AB_1 and Streptomyces gardneri, AB_2 and S. pratensis, AB_3 and S. diastatochromogenes, AB_4 and S. canus, AB_5 and S. albiflavescens, and AB_6 and S. gramineus were 98.67%, 97.59%, 97.33%, 96.54%, 96.94%, and 97.34%, respectively. Pot experiments demonstrated that these six Streptomyces strains prevented tomato bacterial wilt with the efficacy ranging from 69.23% to 100.00%. All the six strains successfully colonized the tomato rhizosphere and exhibited activities of diverse extracellular enzymes including esterase, amylase, and urease. Additionally, they displayed extensive utilization of carbon and nitrogen sources along with robust tolerance towards variations in pH and salt concentrations. [Conclusion] The six strains of Streptomyces exhibited remarkable environmental adaptability and demonstrated efficient colonization in the tomato rhizosphere. Moreover, they displayed potent antagonistic activity against tomato bacterial wilt in pot experiments. These findings align with the principles of sustainable agriculture and provide both theoretical and experimental evidence for utilizing Streptomyces as a preventive and management strategy against tomato bacterial wilt.

[Objective] To address the low denitrification efficiency in high-salinity, and high-nitrate nitrogen wastewater, this study aimed to isolate and identify salt-tolerant denitrifying a strain with high efficiency. And elucidate its underlying mechanisms for enhanced nitrogen removal. [Methods] Morphological characterization and the analysis of its 16S rRNA gene sequence were employed for strain identification. Denitrification performance of bacterial strains was evaluated by measuring different forms of nitrogen. Exploring the mechanism of efficient denitrification of bacterial strains through the RT-qPCR analysis and the measurement of electron transport chain enzyme activity under low oxygen or low oxygen and low C/N ratio conditions. [Results] A halotolerant, facultative aerobic denitrifying bacterium, named W-8, was isolated from saline soil. The strain was identified as Marinobacter sp. This strain can perform denitrification under both aerobic and anaerobic conditions, particularly demonstrating a significant denitrifying activity under low-oxygen conditions (dissolved oxygen concentration<1.2 mg/L). After 48 h of culture under static conditions, W-8 achieved the NO₃^--N (97.85 mg/L) removal efficiency of 95.56% and the total nitrogen removal efficiency of 87.63%. Under low dissolved oxygen, the expression of narG and narI was significantly upregulated, and the activities of electron transport chain complex I and II were enhanced, which promoted the efficient reduction of NO₃^-. The expression of norB was significantly upregulated, promoting the reduction of NO. Under low-oxygen conditions, W-8 further improved the activity of the complex II under a low C/N ratio, reducing carbon source requirements. Under anaerobic conditions, W-8 mainly metabolized NO₃^--N through denitrification, with a gaseous nitrogen production ratio of 87.63%. Under aerobic conditions, this strain achieved nitrogen removal through denitrification combined with assimilation. [Conclusion] Marinobacter sp. W-8 demonstrates exceptional salt tolerance and high-efficiency denitrification. It can significantly reduce sludge production without the need for aeration or strict anaerobic conditions and has a lower demand for carbon sources. It shows great application potential and provides a theoretical and practical basis for efficient, low-cost denitrification.

The preservation and utilization of agricultural microbial resources are essential for achieving green and sustainable agricultural development in China. However, the current state of agricultural microbial resources in China is characterized by a limited total volume, insufficient characterization data, low preservation throughput, poor development, and low sharing efficiency. Establishing and operating advanced agricultural microbial resource repositories can provide high-quality resources for the development of innovative microbial agricultural products and ensure robust sharing of agricultural microbial resources. Based on the construction and operation experience of conventional microbial resource repositories and considering the trends of scientific development in the new era, this paper proposes several insights into the construction and operation of new agricultural microbial resource repositories as a reference for resource repository developers and managers.

Aureobasidium spp. are a group of fungi with remarkable ecological adaptability and stress tolerance. They are ubiquitous in natural environments such as plants and can survive under extreme conditions. The genomes of Aureobasidium spp. show specific differentiation characteristics, and the strains have obviously advantage characteristics in fermentation. Aureobasidium spp. can utilize a broad spectrum of carbon sources and produce a rich variety of metabolites. Aureobasidium spp. and their metabolites have significant application potential in fields such as biomedicine, biocontrol, and food processing. This article introduces the distribution, classification, main metabolites, and multidisciplinary applications of Aureobasidium spp. In the future, with the advancement in multidisciplinary fields such as genome editing and intelligent biomanufacturing, Aureobasidium spp. are expected to play an important role in biomanufacturing and sustainable development industries.

The karst seasonal rainforest of northern tropics in Guangxi is a unique forest ecosystem in China. However, the soil microbial diversity and its maintenance mechanism remain unclear. [Objective] This study explored the distribution characteristics and influencing factors of soil bacterial diversity in a karst seasonal rainforest of northern tropics, aiming to provide a reference for analyzing soil microbial diversity and its maintenance mechanisms in this region. [Methods] Soil samples were collected from a long-term dynamic monitoring plot in the karst rainforest of northern tropics (referred to as the Nonggang plot). The composition and distribution pattern of soil bacterial community were analyzed by 16S rRNA gene amplicon sequencing, and the potential influencing factors were identified by the correlation analysis. [Results] The soil in Nonggang plot harbored a total of 5 841 bacterial operational taxonomic units (OTUs), which were annotated to 1 501 species belonging to 677 genera, 373 families, 242 orders, 104 classes of 35 phyla. The dominant bacterial phyla were Proteobacteria, Actinobacteriota, and Acidobacteriota. The dominant bacterial phylum was Proteobacteria in both the depression and the slope habitats, and Actinobacteriota in the hilltop habitat. The number of total and specific bacterial OTUs displayed a pattern of depression>slope>hilltop habitats. The hilltop habitat association had the fewest total OTUs but the most specific OTUs. The soil bacterial alpha diversity indexes (Chao1, Sobs, Shannon, and Simpson) were not significantly different between the depression and slope habitats, while they were significantly lower in the hilltop habitat. Similarly, the hilltop habitat association had the lowest bacterial alpha diversity indexes than the other associations. The principal coordinate analysis (PCoA) of beta diversity showed differences in the bacterial communities among different habitats and associations. The linear discriminant analysis effect size (LEfSe) identified more differential groups in the depression and hilltop habitats than in the slope habitat. The Spearman correlation analysis, Mantel test and redundancy analysis (RDA) indicated that elevation was the primary factor influencing the distribution of soil bacteria in Nonggang plot, followed by soil organic carbon, available nitrogen, and available phosphorus. Tax4Fun predicted that there were significant differences in the function of soil bacterial communities among different habitats and associations, especially in the hilltop habitat. [Conclusion] This study revealed the community composition and diversity distribution pattern of soil bacteria in Nonggang plot and identified elevation as the primary factor affecting the distribution. These results contribute to the understanding of soil bacterial diversity and its maintaining mechanism in the karst seasonal rainforest of the northern tropics in Guangxi.

[Objective] This study isolated and identified an algicidal bacterium from the East China Sea near Wenzhou and investigated its algicidal characteristics and mechanisms, aiming to contribute a solid scientific basis to the microbial control against red tides. [Methods] The strain was identified by morphological observation, physiological and biochemical tests, and 16S rRNA gene sequence analysis. The algicidal characteristics such as algicidal activity, influences of environmental factors on the algicidal activity, and algicidal specificity were assessed. The algicidal mechanism was explored by electron microscopy, measurements of photosynthetic parameters, and determination of reactive oxygen species (ROS) and malondialdehyde levels and antioxidant enzyme activities. [Results] The algicidal strain J75 was identified as Pseudoalteromonas sp. The algicidal rate of strain J75 against Skeletonemacostatum reached 95.97% within 36 h. Strain J75 induced lysis of algal cells indirectly by secreting extracellular algicidal substances, maintaining the algicidal activity across broad ranges of temperatures (-20 °C to 80 °C) and pH levels (5.0 to 9.0). In addition, strain J75 demonstrated algicidal activities against other harmful microalgae, including Kareniamikimotoi, Prorocentrumminimum, and Phaeocystisglobosa. Under the stress of J75 cell-free supernatant, the algal cells showed morphological structure damage, a significant decrease in the photosynthetic activity, elevations in the levels of ROS, membrane lipid peroxidation, activities of superoxide dismutase, catalase, and peroxidase, and the level of glutathione. These results indicated that strain J75 caused oxidative damage to algal cells, ultimately leading to algal death. [Conclusion] The marine algicidal bacterium Pseudoalteromonas sp. J75, which holds significant potential for the control of red tides, demonstrates its efficacy by secreting algicidal compounds that inhibit the growth of diverse red tide microalgae. The exploration of the algicidal characteristics and mechanisms of this strain provides a theoretical basis for advancing red tide management strategies.

[Objective] To explore the effects of endophytic bacteria in soybean nodules on the growth of soybean seedlings under salt stress and provide reference for the high-quality development of crops in the Yellow River Basin. [Methods] A pot experiment was conducted with the soybean cultivar ‘Xudou 20’ under artificial climate conditions. Three groups were designed: control, salt stress, and salt stress inoculated with endophytic bacteria. The growth of soybean seedlings in each group was measured. [Results] Regarding strain 72, in the case of inoculation with the suspension at OD₆₀₀=0.75 (2:1) and the salt concentration of 200 mmol/L, the activity of catalase (CAT) in the seedlings of 21 days was the highest (2.010 0 U/g FW), which was 54.02% higher than that in the salt stress group; in the case of inoculation with the suspension at OD₆₀₀=0.33 (1:2) and the salt concentration of 300 mmol/L, the proline content was the highest (0.028 6 mg/g); in the case of inoculation with the suspension at OD₆₀₀=0.75 (2:1) and the salt concentration of 100 mmol/L, the proline content was 64.38% higher than that in the salt stress group. Regarding strain 146, the seedlings of 21 days in the case of inoculation with the suspension at OD₆₀₀=0.50 (1:1) and the salt concentration of 50 mmol/L had the highest CAT activity (1.350 0 U/g FW); the seedlings of 28 days in the case of inoculation with the suspension at OD₆₀₀=0.75 (2:1) and the salt concentration of 100 mmol/L had the CAT activity 272.73% higher than that in the salt stress group; the seedlings in the case of inoculation with the suspension at OD₆₀₀=0.75 (2:1) and the salt concentration of 150 mmol/L had the highest proline content of 0.147 0 mg/g, which was 860.78% higher than that in the salt stress group. The results indicated that inoculation with the endophytic bacterial strain 72 or 146 had a repairing effect. The increases in the CAT activity and proline content in the soybean seedlings inoculated with strain 146 over those in the salt stress group were generally higher than those in the case of inoculation with strain 72, indicating that the repairing effect of strain 146 was more obvious. The phylogenetic tree built based on 16S rRNA gene sequences showed that strains 72 and 146 had the highest similarity with Bacillus subtilis (99.45%) and B. protolyticus (100%), respectively. [Conclusion] Inoculating endophytic bacteria was of great significance for alleviating the effect of saline-alkali stress in the Yellow River Basin on the growth of soybean seedlings and developing biological repairing agents.