Biochar and bioorganic fertilizers (BOF) that are used in agriculture can, both directly and indirectly, impact rhizosphere soil microorganisms. However, changes to the halophyte rhizosphere bacterial community after applying biochar and BOF to saline–alkali soil have not been thoroughly described. This study has investigated the bacterial communities of halophytes in saline–alkali soil through the addition of different biochar and BOF formulas using Illumina-based sequencing of the 16S rRNA gene fragment. B_BOF (biochar and BOF combined application) had the best effect, either by promoting the plant growth or by improving the physical and chemical properties of the soil. The concentration of the rhizosphere bacterial communities correlated with the changes in soil organic matter (OM) and organic carbon (OC). Proteobacteria, Actinobacteria, Chloroflexi, and Acidobacteria accounted for >80% of the total bacteria in each treatment. In addition, the abundance of Micromonospora was much higher in response to B_BOF than to the other treatments. BOF, with or without biochar, significantly influenced the bacterial community composition in the saline–alkali soil. The OC, OM, total nitrogen, and the available phosphorus had significant effects on the bacterial structure of this soil. The complex correlation of the bacterial communities between CK and B_BOF was higher compared to that between CK and FB or between CK and BOF. These findings suggested that the plant growth, the soil characteristics, and the diversity or community composition of the rhizosphere bacteria in saline–alkali soil were significantly influenced by B_BOF, followed by BOF, and then biochar; fine biochar had a stronger effect than medium or coarse biochar. This study provides an insight into the complex microbial compositions that emerge in response to biochar and BOF.

The biochar and organic fertilizer amendment have been used as an effective practice to increase soil fertility. Nevertheless, the mechanisms of microbial community response to organic fertilizer and biochar application on saline-alkali soil have not been clarified. This study investigated the effects at different concentrations of organic fertilizer and biochar on the microbial community of wheat rhizosphere soil under field experiment in the Yellow River Delta (China, YRD), using high-throughput sequencing technology. Biochar and organic fertilizer significantly influenced in most soil parameters (p < 0.05), apart from soil moisture content (M), pH, total nitrogen (TN) and soil total phosphorus (TP). Proteobacteria and Actinobacteriota were found in the rhizosphere soil as the main bacterial phyla, and the main fungal phyla were Ascomycota and Mortierellomycota. The soil bacterial and fungal communities under organic fertilizer were distinct from CK. Furthermore, redundancy analysis (RDA) directed that changes in bacterial communities were related to soil properties like pH, available phosphorus (AP), and total organic carbon (TOC), while pH, AP and TP, were crucial contributors in regulating fungal distribution. The correlation between soil parameters and bacteria or fungi varied with the application of biochar and organic fertilizers, and the interaction between the bacteria and fungi in organic fertilizer treatments formed more connections compared with biochar treatments. Our results indicated that biochar was superior to organic fertilizer under the contents set up in this study, and soil parameters increased with biochar and organic fertilizer application rate. The diversity and structure of soil bacteria and fungi differed with the application of biochar and organic fertilizer. The research provides a reference to rational application of organic fertilizer and biochar improvement in saline-alkali soil.

Endophytic bacteria are known to impact the growth and fitness of agriculturally relevant plants. However, there are limited reports describing endophytic bacteria related to mulberry (MorusL.). The present study used Illumina-based 16S rRNA gene sequencing to investigate the endophytic bacterial communities of two mulberry cultivars with differing resistance to low temperature, under cold conditions. In most cases, the bacterial communities of endophytes in the root exhibited higher richness compared with those in the stem, and the communities in resistant cultivar X792 exhibited higher richness compared with those of the sensitive cultivar “Da Shi” (DS). The difference in the proportion of unique operational taxonomic units showed the same trend. The number of genera with significant differences in abundance was greater between organs than between months, and greater between months than between cultivars. Microbial diversity analysis showed that Proteobacteria and Actinobacteria were the dominant phyla in all samples, whilePseudomonas,Steroidobacter, andRhodococcuswere the dominant genera in different samples. There were significant differences between cultivars DS and X792 in the relative abundance ofPseudomonas,Acidibacter,Frigoribacterium,Gaiella, andPseudokineococcus. PICRUSt predictions indicated that the relative abundances of endophytic bacteria in membrane transport and signal transduction were significantly higher in the stem of resistant cultivar X792 in January compared with that of sensitive cultivar DS. Analysis ofβ-Diversity also revealed distinct differences in endophytic bacterial communities of stem and root, and communities of the stem in January and February. The complex correlation of the endophytic communities was higher in sensitive mulberry cultivar DS compared with resistant cultivar X792, in the stem compared with the root, and in January compared with February. Overall, findings from this study suggested that the diversity and community structure of endophytic bacteria in mulberry were significantly influenced by organs and months, followed by the host cultivar. The study provides insight into the complex microbial diversity of mulberry under cold conditions.

Intestinal microbes are known to impact the growth and development of insects. However, there are few reports on the intestinal microbiota of silkworms (Bombyx mori). The present study used Illumina 16S rRNA gene sequencing to investigate the changes over time in the intestinal bacteriome of fifth-instar silkworms fed mulberry leaf (MB) or artificial diet (AD). The results showed that the intestinal microbiota richness was significantly higher, before the 4th day of the fifth instar, in the silkworms fed AD rather than MB, while the richness was consistent between the AD and MB groups directly before cocooning. Proteobacteria was the most dominant phylum in MBs, AD, and the silkworm intestinal bacteriome, regardless of sex, feed type, or date, except that Firmicutes was the most dominant phylum for females on the 6th day of the fifth instar. Acinetobacter was the dominant genus in silkworms fed MB, while Enterococcus was the dominant genus in silkworms fed AD. Only 3.62% of the intestinal microbiota of silkworms fed MB was derived from MB, while 13.71% of the intestinal microbiota of silkworms fed AD was derived from AD. Thus, both bacterial communities were dominated by bacteria of unknown origin (non-feed sources). In the correlation network analysis, the silkworms fed AD appeared to have more complex interactions than the silkworms fed MB. Proteobacteria was the phylum most closely related to silkworm cocoon quality and feeding efficiency. Pantoea was the genera most closely related to cocoon quality and silkworm feeding efficiency in silkworms fed MB. AD had a significant impact on the predicted functions of the intestinal microbiota. There were significant differences in all six KEGG level 1 functions and all BugBase (except for Gram_Positive) phenotypes between silkworms fed AD or MB. The BugBase “Aerobic” phenotype was significantly higher in females compared to males, in both the AD and MB groups, while the “Oxidative_Stress_Tolerant” phenotype was the opposite. Overall, the findings suggest that the diversity, community structure, and predicted functions of intestinal bacteria in silkworms were significantly influenced by feed type. The study provides insights into the complex silkworm intestinal bacterial diversity and a foundation for probiotic screening.

Peanut productivity is severely restricted by soil salinization and associated nutrient deficiency in saline soil. The quinoa–peanut relay intercrop pattern (IP) is a promising planting system that utilizes the biological advantages of quinoa to improve soil ecological functions and productivity. However, the effects of IP on soil physicochemical and biological properties and the yield formation of the combined peanut crop are still unclear. Two-year field experiments in coastal saline soil were conducted to explore the effects of IP on peanut growth and pod yield, soil physicochemical properties, and microbial community characterization at different growth stages of peanut based on the traditional monocrop pattern (MP). The results show that IP promoted peanut pod yield, although there was the disadvantage of plant growth at an early stage. Soil water content, electrical conductivity (EC), and Na⁺ content in the peanut rhizosphere were lower, whereas K⁺, NH₄⁺, and total organic carbon (TOC) contents were higher in IP systems at both the vegetative and reproductive stages. The pod yield of peanut was significantly negatively correlated with soil EC and Na⁺ contents at the vegetative stage, but positively correlated with K⁺, NO₃⁻, NH₄⁺, PO₄³⁻, and TOC contents at the reproductive stage. IP rebuilt the composition of the soil bacterial community in the peanut rhizosphere and increased the abundance of the beneficial bacterial community, which were positively correlated with soil TOC, K⁺, NH₄⁺, NO₃⁻, and PO₄³⁻ contents. These findings suggest that IP can increase peanut pod yield through optimizing soil physicochemical properties and microbial community composition, and it is a promising planting system for improving agricultural production in coastal saline lands.