Phosphorus (P) is one of the essential macronutrients for plant growth, being a highly required resource to improve the productive performance of several crops, especially in highly weathered soils. However, a large part of the nutrients applied in the form of fertilizers becomes “inert” in the medium term and cannot be assimilated by plants. Rationalizing the use of phosphorus is a matter of extreme importance for environmental sustainability and socioeconomic development. Therefore, alternatives to the management of this nutrient are needed, and the use of P-solubilizing microorganisms is an option to optimize its use by crops, allowing the exploration of less available fractions of the nutrient in soils and reducing the demand for phosphate fertilizers. The objective of this study is to discuss the importance of phosphorus and how microorganisms can intermediate its sustainable use in agriculture. In this review study, we present several studies about the role of microorganisms as phosphorus mobilizers in the soil. We describe the importance of the nutrient for the plants and the main problems related to the unsustainable exploitation of its natural reserves and the use of chemical fertilizers. Mainly we highlight how microorganisms constitute a fundamental resource for the release of the inert portion of the nutrient, where we describe several mechanisms of solubilization and mineralization. We also discussed the benefits that the inoculation of P-solubilizing microorganisms provides to crops as well as practices of using them as bioinoculants. The use of microorganisms as inoculants is a viable resource for the future of sustainable agriculture, mainly because its application can significantly reduce the application of P and, consequently, reduce the exploitation of phosphorus and its reserves. In addition, new research must be conducted for the development of new technologies, prospecting new biological products, and improvement of management practices that allow for higher efficiency in the use of phosphorus in agriculture.

Agriculture is a fundamental activity for human development. However, its sustainable practice is required to ensure the perpetuity of future resources. In this way, bacteria can benefit crops by making available nutrients and metabolites, mainly contributing to reducing the demand for chemical fertilizers. This study aimed to evaluate the biofertilizing capacity of Azospirillum brasilense, Bacillus megaterium, and Brevibacillus fluminis and their effects on improving the physiological and morphoanatomical properties of strawberry seedlings. In vitro tests were performed to evince their potential to supply nutrients (P and K) and produce siderophores and indole-acetic acid. In an inoculation experiment, these strains were inoculated in isolation and mixed in pairs and triples. This experiment was carried out in a greenhouse in a completely randomized design (CRD). The inoculated treatments were fertilized with 30% N and P demands; the uninoculated control received 30% and 100% of these demands. Leaf gas exchange, total chlorophylls, and crown diameter were evaluated during cultivation. After 138 days, leaf number, nutrient content, root length, root and shoot fresh and dry weight, and total seedlings were evaluated. The bacteria tested positive in all in vitro evaluations except for siderophore production. The strawberry responded positively to inoculation. The inoculation, either in isolation or in a mixture, improved stomatal conductance, leaf transpiration, internal CO₂ concentration, leaf N and Mg contents, crown diameter, leaf area, and root elongation. We can conclude that the intermediation of microorganisms improves nutrient use efficiency and reduces the strawberry’s fertilizer demand by up to 70%, leading to plant development and yields comparable to complete fertilization.

Water scarcity, intensified by climate change, threatens tomato ( Solanum lycopersicum ) productivity, impacting growth, metabolism and secondary metabolite production. This study evaluated the effects of Azospirillum brasilense and Bacillus amyloliquefaciens inoculation in mitigating water stress in the Ibiza cultivar under 100%, 50% and 25% water replenishment. Severe water deficits significantly reduced morphological parameters, such as height, leaf number and dry mass. However, inoculation with B. amyloliquefaciens , particularly in combination with A. brasilense , enhanced dry mass accumulation, stem diameter and root development. Physiological analyses revealed higher electrolyte leakage and compromised membrane integrity due to water stress. Biochemical responses included increased antioxidant enzyme activity (SOD, CAT and APX) and proline accumulation, both modulated by bacterial inoculation. Interestingly, chlorophyll content increased at 25% water availability, suggesting an adaptive mechanism, while DNA content decreased. Secondary metabolites (flavonoids and phenolics) also responded to the interaction between irrigation levels and bacterial inoculation. The findings demonstrate that inoculation with A. brasilense and B. amyloliquefaciens is an effective approach to enhance tomato tolerance to water deficits by improving agronomic performance, strengthening antioxidant defences and regulating secondary metabolite production. This strategy supports the development of sustainable and adaptive agricultural practices in the face of increasing water scarcity.

The threatened orchid Cattleya milleri is a microendemic orchid of a Brazilian savanna hotspot. As endophytes and mycorrhizae may improve its propagation and conservation, we investigated its root fungal community. Cattleya milleri roots were sampled in five natural sites and at a greenhouse. Fungal root endophytes were isolated for characterization and molecular ITS (Internal Transcribed Spacer) identification. Total DNA was extracted from endorhiza and rhizosphere for ITS amplification and sequencing. Sixteen fungal isolates were clustered in 6 Operational Taxonomic Units (OTUs) and endorhizal and rhizospheric sequences were clustered in 327 OTUs. Endorhiza presented from 25 to 89 OTUs, and rhizosphere 56 OTUs. Cluster analysis showed high divergence between natural and greenhouse fungal communities, but similarity among natural samples. From the 94 genera, 24 were annotated as endophytes, two mycorrhizas, 33 pathotrophs, 40 saprotrophs, and 17 symbiotrophs based on the FunGuild database. Endophytes of the orders Capnodiales, Hypocreales, Pleosporales, and mycorrhizae of Sebacinales occurred in all sites. The mycorrhizae Tulasnella occurred in all natural samples. The interaction with only two mycorrhizal taxa may limit C. milleri distribution. However, the recruitment of many non-mycorrhizal endophytes is essential to natural development. Pleosporales, Tulasnella, and Sebacinalles may be considered for C. milleri propagation and conservation.

Purpose: Strawberries are widely consumed worldwide, known for their adaptability to various climatic regions and unique organoleptic properties. However, conventional strawberry production relies heavily on synthetic fertilizers, which, while effective in promoting plant growth and yield, contribute to environmental degradation and increase production costs. This study evaluated the effects of inoculating strawberry plants with the bacteria Azospirillum brasilense, Bacillus megaterium, and Brevibacillus fluminis, both individually and in consortia, under reduced fertilization regimes. Methods: Key physical, commercial, and chemical parameters of the fruits were measured, including pH, total titratable acidity, and phenolic compound content. Additionally, an exploratory economic analysis was conducted to assess how substituting synthetic fertilizers with bioinputs can reduce agricultural production costs while promoting ecological sustainability. Results: The inoculation, particularly the combination of A. brasilense and B. fluminis, significantly increased the proportion of marketable fruits, as well as fruit weight and diameter, compared to uninoculated plants fertilized at 30% of nitrogen and phosphorus demand. The triple bacterial inoculation further improved fruit quality by increasing pH, reducing total acidity, enhancing the sweetness index, and elevating phenolic compound levels. Predictive economic analysis demonstrated that reducing fertilizer use by up to 70% increased net value and lowered costs without negatively affecting production. Conclusions: These results indicate that bacterial inoculation is a promising strategy for sustainable strawberry cultivation, improving agronomic performance and fruit quality while reducing dependency on synthetic fertilizers. The application of this research could lead to the development of effective biofertilizers that mitigate environmental impacts and foster more sustainable agricultural practices.