The bacterial communities in rhizosphere soil interact with the roots of plants. This interaction is beneficial for both the bacteria and the plants, which makes it very important to identify the structure of these bacterial communities for plant growth and development. However, the composition characteristics of bacterial communities in rhizosphere soil of 2-year and 5-year Haloxylon ammodendron have not been clearly defined. The purpose of this study was to identify the diverse composition of 2-year and 5-year Haloxylon ammodendron in Turpan, Xinjiang. Thus, rhizosphere soil bacteria were analyzed by isolating, purifying, and identifying the species through high-throughput sequencing technology. The bacterial strains in the rhizosphere soil of Haloxylon ammodendron were isolated with the dilution coating method, resulting in 37 isolated strains. The selective media were used to screen the growth-promoting characteristics of the rhizosphere soil isolates of Haloxylon ammodendron. The results of high-throughput amplification sequencing showed that the rhizosphere bacteria in the 2-year rhizosphere soil belonged to 45 phyla, 109 classes, 288 orders, 451 families, 826 genera, and 404 species, and those in the 5-year rhizosphere soil belonged to 56 phyla, 148 classes, 369 orders, 601 families, 1062 genera, and 671 species. Among them, Firmicutes, Proteobacteria, Actinobacteriota, Bacteroidota, Crenarchaeota, and so on are the dominant bacteria. There were 12206 and 14,053 OTUs in the 2-year-old and 5-year-old rhizosphere soil bacteria, respectively, and 3329 OTUs in the 2-year- and 5-year-old rhizosphere soil, accounting for 16.98% of the total number of OTUs. The results showed that three strains, sg16, sg21, and ss4, had the highest inorganic phosphorus solubility index (1.58). The isolated strain did not have the ability to dissolve organophosphorus and potassium, while the screened strain sg16 had the ability to fix nitrogen. Two strains with a good iron-bearing capacity, Sg9F and Sg1, were screened, among which Sg9F had the highest D/d value and Sg9F had the strongest iron-bearing capacity. The results showed that 37 strains of rhizosphere soil bacteria belonged to six genera. They are Bacillus, Corynebacterium, Phyllobacterium, Lysinibacillus, Sinorhizobium meliloti, and Streptomyces levis. Among them are sg21 (Bacillus sp.), sg1 (Bacillus sp.), sg9F (Streptomyces levis), sg16 (Phyllobacterium phragmitis), and ss4 (Sinorhizobium meliloti). This study provides a particular research basis for the influence of Haloxylon ammodendron rhizosphere bacteria on soil nutrient release and depicts a solution for improving the yield and quality of cistanche deserticola indirectly through isolating, screening, and identifying rhizosphere soil bacteria, including screening strains with growth-promoting functions and analyzing the population structure of rhizosphere bacteria in 2- and 5-year soil in combination with high-throughput sequencing technology.

Rhizosphere microorganisms effectively exploit nutrient resources within the rhizosphere, while growth-promoting bacteria in this environment play a vital role in regulating soil fertility and enhancing plant health. In this study, we utilized a comprehensive approach that included the isolation, purification, and identification of dominant microorganisms, alongside high-throughput sequencing technology. This methodology was employed to analyze the primary microbial groups and their diversity within the rhizosphere soil of Helichrysum arenarium (L.) Moench in Altay, Xinjiang, China. By isolating bacterial strains from the rhizosphere soil using a dilution coating method, we successfully obtained 43 distinct strains. Subsequently, selective media were employed to screen for growth-promoting characteristics among these isolated strains derived from the rhizosphere soil of H. arenarium (L.) Moench. The results, obtained through high-throughput amplification sequencing, revealed diverse bacterial communities belonging to 35 phyla, 93 orders, 215 families, 324 genera, and 231 species associated with H. arenarium (L.) Moench, as well as fungal communities comprising 14 phyla, 47 orders, 96 families, 204 genera, and 571 species present in the rhizosphere soil. Among these identified communities, Actinobacteriota emerged as the predominant bacterial phylum while Ascomycetes and Mortieromycetes were recognized as the principal fungal phyla found in the rhizospheric soil of H. arenarium (L.) Moench. Analysis of culturable bacteria’s promotion activity within this rhizospheric environment indicated that three strains—S16, S31, and S29—exhibited the highest solubility index for inorganic phosphorus; additionally, the screened strains S7 and S10 demonstrated nitrogen-fixing capabilities. Furthermore, ten strains exhibiting excellent iron-bearing capacities were identified; notably, strain S16 displayed the highest D/d value indicating, its superior iron-bearing capacity. The growth-promoting bacteria were identified as Kocuria rosea, Priestia megaterium, Bacillus mobilis, Bacillus bataviensis, three variants of Bacillus mycoides, Bacillus paramobilis, Bacillus sonorensis, and Alcaligenes faecalis. This study provides a foundational understanding of how microorganisms in the rhizosphere of H. arenarium (L.) Moench influence soil nutrient release and offers valuable insights into enhancing yield and quality cultivation by isolating, screening, and identifying growth-promoting bacteria from rhizosphere soil.

Rhizosphere microorganisms can utilize nutrient resources in the rhizosphere efficiently, while rhizosphere growth-promoting bacteria play a crucial role in regulating soil fertility and promoting plant health. In this study, we employed a combination of isolation, purification, identification of dominant microorganisms, and high-throughput sequencing technology to analyze the main microbial groups and diversity in the rhizosphere soil of Helichrysum arenarium（L.）Moench. in Altay, Xinjiang，China. By isolating bacterial strains from the rhizosphere soil using a dilution coating method, we successfully obtained 43 strains. Subsequently, selective medium was utilized to screen for growth-promoting characteristics among these isolated strains from the rhizosphere soil of H. arenarium（L.）Moench.. The results obtained through high-throughput amplification sequencing revealed that the rhizosphere soil harbored diverse bacterial communities belonging to 35 phyla, 93 orders, 215 families, 324 genera and 231 species associated with H. arenarium（L.）Moench., as well as fungal communities consisting of 14 phyla ,47 orders ,96 families ,204 genera and 571 species. Among these bacterial communities identified, eight phyla exhibited relative abundances exceeding 1%, with Actinobacteriota being most predominant at an abundance rate of 41.30%. Additionally,five bacterial genera were found to have relative abundances exceeding 1% ,with Arenimicrobium_luteum being most abundant at 6.11% . Furthermore,four fungal phyla displayed relative abundances surpassing1 % ,with Ascomycota accounting for 67.21% of total fungal community composition.Finally,four fungal genera demonstrated relative abundances higher than 1% ,with Knufia representing 3.80% of total fungal community composition.The analysis on culturable bacteria's promotion activity within the rhizospheric soil indicated that two strains,S16and S29, exhibited the highest solubility index for inorganic phosphorus. However, it lacked the ability to dissolve organophosphorus and potassium. On the other hand, strains S7 and S10, which were screened, demonstrated nitrogen-fixing capabilities. Nine strains with excellent iron-bearing capacity were identified, with strain S16 exhibiting the highest D/d value and strongest iron-bearing capacity among them. Our findings revealed that 43 rhizosphere soil bacteria belonged to three genera. The ten growth-promoting bacteria were identified as Kocuria rosea, Priestia megaterium, Bacillus mobilis, B. bataviensis, B. mycoides (two strains), B. paramobilis, and Alcaligenes faecalis. This study provides a particular research basis for the influence of H. arenarium（L.）Moench. rhizosphere microorganisms on soil nutrient release and depicts a solution for improving the yield and quality cultivation of H. arenarium（L.）Moench. by isolating, screening, and identifying rhizosphere soil growth-promoting bacteria, including screening strains with growth-promoting functions and analyzing the population structure of rhizosphere and habitat soil in combination with high-throughput sequencing technology.