Bacterial communities play an important role in mangrove ecosystems. In order to gain information on the bacterial communities in mangrove species and rhizospheres grown in Zhangjiangkou National Mangrove Nature Reserve, this study collected root, branch, and leaf samples from five mangrove species as well as rhizosphere and non-rhizosphere samples and analyzed the community structure of endophytic bacteria and bacteria in rhizosphere and non-rhizosphere using Illumina high-throughput sequencing technique. Bacteria in 52 phyla, 64 classes, 152 orders, 295 families, and 794 genera were identified, which mainly belonged to Proteobacteria, Cyanobacteria, Actinobacteria, Firmicutes, Bacteroidetes, Fusobacteria, and Nitrospirota. At each taxonomic level, the community structure of the rhizosphere bacteria varied slightly with mangrove species, but endophytic bacteria differed greatly with plant species. The diversity indices of endophytic bacteria in branch and leaf samples of Acanthus ilicifolius were significantly lower, and endophytic bacteria in the plant tissues had higher abundance in the replication/repair and translation Clusters of Orthologous Genes functional categories but lower abundance in the carbohydrate metabolism category. This study helps to understand the community structure and diversity characteristics of endophytic and rhizosphere bacteria in different mangrove plants. Provide a theoretical basis for in-depth research on the functions of mangrove ecosystems.
High rainfall environmental conditions can easily cause erosion or collapse of the granite residual soil slope. However, traditional slope reinforcement methods have drawbacks such as poor landscape effect, high energy consumption of raw materials, and environmental pollution. This study studied the application of microbial-induced calcite precipitation (MICP) in the reinforcement of granite residual soil. The consolidation effect of various methods was investigated, and the influence of cementing liquid concentration and pH value on consolidation under optimal curing conditions was explored. The results showed that the bacteria concentration reached OD600 = 3.0 and urease activity was 31.64 mM/min, which positively impact the production of calcium carbonate and the stability of crystal morphology. In addition, the soaking method was found to have the most effective consolidation effect on the surface soil samples, with the lowest disintegration rate. On the other hand, the peristaltic pump grouting method is the most effective in strengthening depth. This method resulted in a 513.65% increase in unconfined compressive strength (UCS), a 297.98% increase in cohesion, and a 101.75% increase in internal friction angle. This study also found that after seven rounds of grouting, the highest UCS was achieved in consolidated soil samples with a 0.5 mol/L cementing solution concentration, reaching 1.602 MPa. The UCS of soil samples increases as the pH value of the cementing fluid increases within the range of 6–8. As the pH value reaches 8–9, the strength increases and stabilizes gradually. These research findings can serve as an experimental basis for strengthening granite residual soil slopes and a guide for improving microbial geotechnical strengthening methods.
Flammulina filiformis is a popular mushroom which has been regarded as a potential model fungus for mycelium growth, fruiting body development, and stress response studies. Based on a genome-wide search, four genes encoding heterotrimeric G protein α subunits were identified in F. filiformis. The data of conserved domain analysis showed that these genes contain only one subgroup I of Gα subunit (Gαi), similar to many other fungi. To explore the function of Gαi, FfGa1 over-expression (OE) and RNA interference (RNAi) strains were generated using the Agrobacterium tumefaciens-mediated transformation (ATMT) approach. RNAi transformant strains showed remarkably reduced growth on PDA medium and added sensitivity to cell wall-enforcing agents with maximum growth inhibition, but showed better growth in response to hypertonic stress-causing agents, while OE strains exhibited more resistance to thermal stress and mycoparasite Trichoderma as compared to the wild-type and RNAi strains. Taken together, our results indicated that FfGa1 positively regulates hyphal extension, and is crucial for the maintenance of cell wall integrity and protection against biotic and abiotic (hypertonic and thermal) stress.
26 March 2024 in Journal of Agricultural and Food Chemistry