The intensive use of synthetic fertilizers and pesticides has increased crop productivity but also contributed to soil degradation and biodiversity loss, highlighting the need for more sustainable agricultural strategies. Among emerging solutions, plant growth-promoting rhizobacteria (PGPR), particularly members of the Bacillota phylum, are gaining attention as effective bioinoculants that enhance plant growth and tolerance to biotic and abiotic stresses. However, introduced strains do not function in isolation. They enter complex microbial communities, shaped by plant type and developmental stage, influenced by soil properties and environmental conditions. While the positive effects of PGPR on plant performance are well documented, their impact on indigenous rhizosphere microbiota remains less studied. This review synthesizes current knowledge on how Bacillota-based inoculants influence native microbial communities in cereals, vegetables, orchard crops, and fiber plants. Most studies report shifts toward plant-beneficial taxa and reduced abundance of potential pathogens following Bacillota application. Frequently enriched genera include Bacillus , Pseudomonas , Lysobacter , Sphingomonas , Streptomyces , Azotobacter , Arthrobacter , Pseudarthrobacter , Bradyrhizobium , Devosia , Flavobacterium , Klebsiella , Herbaspirillum , and Rhodanobacter . These changes are often associated with improved plant growth and yield, and stress resilience. However, responses strongly depend on strain, plant and methodological approach. We summarize commonly applied approaches used to assess these interactions. Despite technological advances, limitations remain, such as single time-point sampling, simplified experimental systems, and insufficient integration of inoculant persistence with community analyses. Standardized, multi-site experimental frameworks, with multiple sampling terms are needed to improve predictability and ensure the safe implementation of PGPR-based solutions in sustainable agriculture.

The intensive use of mineral nitrogen fertilizers in cereal production contributes to environmental degradation, highlighting the need for more sustainable crop management strategies. Plant growth-promoting bacteria (PGPB) offer a promising alternative; however, their effects on native rhizosphere communities remain underexplored, particularly in barley. This study evaluates the impact of a bacterial consortium composed of Paenibacillus sp. Z15 and Pseudomonas sp. KR227 on barley growth, yield, and rhizosphere bacteria under field conditions in temperate climate (2025). Plant biometric traits, photosynthetic pigment content, and soil properties were measured, and rhizobacterial communities were analyzed using 16S rRNA gene (V3–V4) sequencing. The PGPB consortium significantly increased early root biomass (120%), shoot height (7.8%), and grain yield (15.5%), while no significant effects were observed on soil chemistry or photosynthetic pigments. Sequencing revealed no major changes in alpha or beta diversity; however, transient shifts in the relative abundance of specific taxa were detected relatively shortly after inoculation and mostly disappeared by harvest. These findings indicate that the Paenibacillus–Pseudomonas consortium can enhance barley performance without disrupting native rhizobacterial communities. Overall, the results support the potential of PGPB as a sustainable agronomic tool and provide new insights into PGPB–microbiome interactions in barley under field conditions.

Sustainable care of urban lawns requires methods that maintain high turf quality while reducing the use of chemical fertilizers. The objective of this three-year field study was to evaluate whether microbial inoculants can complement or partially substitute conventional fertilization (65–190 kg N·ha⁻¹, 33–35.2 kg P·ha⁻¹, and 124.5 kg K·ha⁻¹) required to maintain high turf quality in an intensively managed lawn system. The experiment was conducted in Poland on a degraded chernozem, classified as Haplic Phaeozem. A standard mixture of perennial ryegrass and fescue was evaluated under four treatments: (1) untreated control; three commercial microbial formulations: (2) StymGrass P+K, containing nutrient-solubilizing Bacillus spp.; (3) BioVitaGrass, combining Bacillus spp. with arbuscular mycorrhizal fungi (AMF); and (4) NitroGrass, containing nitrogen-fixing Azotobacter spp. with Bacillus spp. All microbial treatments improved lawn quality compared with the untreated control. Lawns receiving BioVitaGrass or NitroGrass showed the strongest responses, including denser plant cover, greener and finer leaves, reduced disease symptoms, and increased concentrations of nutrients in the plant tissue. StymGrass P+K produced smaller but still positive effects. Measurements of plant conditions, such as leaf greenness and canopy development, also indicated improved photosynthetic activity in inoculated plots. These results support the role of plant growth-promoting bacteria (PGPB) and arbuscular mycorrhizal fungi in nutrient mobilization, root stimulation, and stress resilience. Although most evidence comes from crops, this study provides novel field-based confirmation of multi-functional microbial inoculant efficacy in turfgrass under this study’s conditions.

Maintaining high-quality functional and recreational turfgrass requires effective management practices that support turf performance under field conditions. One promising strategy involves the use of plant growth-promoting microorganisms. The aim of this study was to evaluate the effect of Bacillus sp. N188 on turf quality and functional performance. A field experiment was conducted in 2024–2025 under the conditions of southern Poland on Haplic Phaeozem soil. The study included two lawn mixtures differing in species composition and intended use: “Uniwersalna U-1” and “Super Trawnik”. The experimental design comprised control treatments and variants with annual application of a preparation containing Bacillus sp. N188. Turf quality was assessed according to the COBORU methodology, including visual traits (overall appearance, turf density, leaf colour and structure, and disease susceptibility), as well as physiological indices (NDVI, LAI, SPAD) and selected indicators of functional value. The application of Bacillus sp. N188 significantly improved turf quality compared to the control treatments. An increase in sward density and uniformity, more intense leaf coloration, improved structural characteristics, and reduced incidence of fungal diseases were observed. The physiological indices confirmed improved plant condition in plots treated with the bacterial preparation. The positive effects of Bacillus sp. N188 were observed in both lawn mixtures, although the magnitude of the response varied depending on species composition. The results indicate that Bacillus sp. N188 has potential as a plant biostimulant for improving the aesthetic and functional properties of turfgrass under temperate climatic conditions.