Plant-growth-promoting rhizobacteria (PGPR) increase the germination percentage and the vigor of seeds, thus determining aspects for the efficient production of seedlings and the prompt establishment of crops in the field. In this study, the effect of the biopriming of rhizobacteria was evaluated: Bacillus cereus (KBEndo4P6), Acinetobacter radioresistens (KBEndo3P1), Pseudomonas paralactis (KBEndo6P7), and Sinorhizobium meliloti (KBEkto9P6) on some parameters such as the percentage of germination and vigor and the germination index, among others, as well as the synthesis of phytocompounds in the seeds of Cucumis sativus L. biopriming seeds significantly improved germination, the germination index, the vigor, the plumule and the radicle length, in addition to an increase in phytochemical compounds. The rhizobacteria KBEndo3P1 increased the germination percentage by 20%, the germination index by 50%, and the seed vigor by 60%, as well as the length of the radicle by 11%, and the plumule by 48% compared to the control, and the total phenols and antioxidants increased by 9% and 29%, respectively. Biopriming with plant-growth-promoting rhizobacteria increases germination, which allows for the possibility of more outstanding production of seedlings and a greater length of the radicle, thus increasing the efficiency in the processes of water and nutrient absorption and improving its establishment in the field. In addition, the production of phytocompounds enhances their response against any type of stress, making them a viable alternative in sustainable agriculture to increase cucumber yield.

Vermicomposting is a sustainable biotechnological process that transforms organic waste through the synergistic activity of earthworms, such as Eisenia fetida, and their associated microbiota. This study evaluated bacterial and physicochemical dynamics during the vermicomposting of bovine manure by analyzing the microbial composition of the substrate and the gut of E. fetida at three time points (weeks 0, 6, and 12). The V3–V4 region of the 16S rRNA gene was sequenced, and microbial diversity was characterized using QIIME2. Significant differences in alpha diversity (observed features, Shannon index, and phylogenetic diversity) and beta diversity indicated active microbial succession. Proteobacteria, Bacteroidota, and Actinobacteriota were the dominant phyla, with abundances varying across habitats and over time. A significant enrichment of Proteobacteria, Bacteroidota, and the genera Chryseolinea, Flavobacterium, and Sphingomonas was observed in the manure treatments. In contrast, Actinobacteriota, Firmicutes, and the genera Methylobacter, Brevibacillus, Enhygromyxa, and Bacillus, among others, were distinctive of the gut samples and contributed to their dissimilarity from the manure treatments. Simultaneously, the physicochemical parameters indicated progressive substrate stabilization and nutrient enrichment. Notably, the organic matter and total organic carbon contents decreased (from 79.47% to 47.80% and from 46.10% to 27.73%, respectively), whereas the total nitrogen content increased (from 1.70% to 2.23%); these effects reduced the C/N ratio, which is a recognized indicator of maturity, from 27.13 to 12.40. The macronutrient contents also increased, with final values of 1.41% for phosphorus, 1.50% for potassium, 0.89% for magnesium, and 2.81% for calcium. These results demonstrate that vermicomposting modifies microbial communities and enhances substrate quality, supporting its use as a biofertilizer for sustainable agriculture, soil restoration, and agrochemical reduction.

Due to increasing soil degradation caused by unsustainable agricultural practices and the continued demand for quality food for the human population, it is imperative to find sustainable strategies for high-quality food production. For this reason, the objective of the present study was to evaluate the interaction between the factors of consortium of phosphorus-solubilizing rhizobacteria, addition of phosphate rock and worm load in horse manure to produce an organic fertilizer fortified with phosphorus. For this, consortia of phosphate-solubilizing rhizobacteria of the genus Bacillus (Bacillus aryabhattai, Bacillus subtilis and Bacillus cereus) isolated from the rhizosphere of Distichlis spicata were inoculated. Igneous phosphate rock (0 and 2%) was added in the vermicomposting process (with 25 and 50 g of E. fetida worms per kg of horse manure). The results obtained show that there is a significant interaction between the factors of inoculation with bacterial consortia (1 × 10⁸ CFU mL⁻¹), phosphate rock (2%) and earthworm biomass (50 g kg⁻¹ of manure), and that this interaction promotes the production of assimilable forms of phosphorus for plants (such as monobasic phosphate ions H₂PO₄⁻¹ or dibasic phosphate ions HPO₄⁻²) within the vermicomposting process, having as a product an organic substrate supplemented with the optimal nutritional requirements for the development and growth of crops. This work can serve as a basis to produce high-quality organic fertilizer. However, field studies are required in order to observe the impact of vermicompost on the yield and quality of the fruits, and it can be compared with other types of fertilizers and the relevance of their use in different types of climates.

Pecan cultivation holds significant global importance. Salinity negatively affects the physiology and metabolism of the plant. However, certain plant growth-promoting rhizobacteria (PGPR) have the ability to reduce salt stress in plants. The objective was to analyze the effects of the rhizobacteria Bacillus paralicheniformis strain LBEndo1 on the development of pecan seedlings under salinity stress conditions. Two factors were analyzed: the presence of saline stress and the bacterial inoculation. The bacterial application was conducted at a concentration of 1 × 10⁸ CFU/mL, and irrigation was administered every third day with 80 mL of water containing 50 mM NaCl. The results show that the rhizobacteria has a maximum tolerance of 15% salinity. Furthermore, the inoculation of PGPR significantly increased the biomass of the seedlings, including the dry weight of leaves, stem, and roots, as well as the stem diameter and height. Furthermore, seedlings that interacted with the rhizobacteria exhibited superior development under saline conditions, with significant increases of 105.5% in chlorophyll concentration and 112% in proline accumulation compared to non-inoculated seedlings. Additionally, a remarkable reduction in leaf damage caused by salt stress was observed. In conclusion, the LBEndo1 rhizobacteria, being a strain resistant to salinity and possessing multiple mechanisms to promote growth while mitigating salt stress, has the potential to be utilized in pecan seedlings to alleviate stress caused by salinity and increases biomass.

Soil salinity is a major abiotic stressor that negatively impacts agricultural productivity worldwide. One potential strategy to alleviate its effects is the use of plant growth-promoting rhizobacteria (PGPR). This study evaluated the impact of PGPR (Pseudomonas paralactis, Bacillus cereus, Sinorhizobium meliloti, and Acinetobacter radioresistens) on cucumber seedling (Cucumis sativus L.) growth under saline stress conditions (0, 5, 10, and 15% of NaCl). The results showed that PGPR biopriming significantly enhanced germination rates, plumule and radicle lengths, fresh and dry weights compared to non-inoculated controls. Notably, the highest germination rates were observed with P. paralactis and A. radioresistens at 81.20% and 79.39%, respectively, under saline stress. Additionally, PGPR inoculation enhanced chlorophyll content, proline accumulation, and antioxidant activity, indicating improved photosynthetic efficiency and osmotic adjustment under saline conditions. These findings suggest that PGPR inoculation is an effective, sustainable strategy for mitigating the detrimental effects of salt stress, improving cucumber seedling development. In order to increase the benefits of PGPR, further evaluations are being pursued using bacterial consortia to maximize individual effects and further improve plant growth under these conditions.

Soil salinity imposes a critical constraint on plant productivity, highlighting the need for sustainable biological strategies to enhance stress tolerance. This study assessed the effects of volatile organic compounds (VOCs) emitted by ten plant-growth-promoting rhizobacteria (PGPR) isolated from the rhizosphere of Euphorbia antisyphilitica on the growth of Arabidopsis thaliana seedlings exposed to 0, 50, and 100 mM NaCl. A divided Petri dish system was used to quantify biomass, root architecture, proline accumulation, sodium content, and chlorophyll concentration. Three strains—Siccibacter colletis CASEcto12, Enterobacter quasihormaechei NFbEcto18, and Bacillus wiedmannii NFbEndo12—significantly enhanced seedling development under saline and non-saline conditions (p ≤ 0.05). At 50 mM NaCl, S. colletis CASEcto12 increased primary root length from 40.25 to 64.81 mm and fresh weight from 45.05 to 133.33 mg, while E. quasihormaechei NFbEcto18 elevated lateral root number from 10 to 24, compared to the uninoculated control. Under 100 mM NaCl, E. quasihormaechei NFbEcto18 increased proline accumulation (0.564–1.378 mmol g⁻¹ FW) and reduced Na⁺ content (0.146–0.084 mmol g⁻¹ FW), indicating improved osmotic and ionic regulation. VOC profiling using SPME-GC-MS revealed aldehydes, ketones, and alcohols as predominant classes. Overall, these findings demonstrate the potential of candelilla-associated PGPR VOCs as promising biostimulants for enhancing plant performance in salt-affected soils.