Inorganic phosphate solubilization Dotaz Zobrazit nápovědu
This study evaluates the efficiency of Phosphate solubilizing bacteria isolated from Effluent Treatment Plant sludge of Paradeep Phosphate Limited, Odisha, India, to solubilize rock phosphate (RP) and the mechanism and structural changes during solubilization investigated by scanning electron microscopy (SEM), X-ray diffraction (XRD), and Fourier-transform infrared spectroscopy (FTIR). Out of 13 bacterial isolates, Bacillus cereus S0B4, Solibacillus isronensis S0B8, and Bacillus amyloliquefaciens S0B17 strains were found to be the best RP solubilizers. This is the first report on S. isronensis S0B8 with the ability to solubilize RP. In particular, the potent strain B. cereus S0B4 showed maximum soluble P (338.5 mg/L) on the 7th day. Negative correlations (r = -0.70; p ≤ 0.01) were observed between soluble P concentration and pH, whereas positive correlation exists with the growth of B. cereus S0B4 (r = 0.91, p ≤ 0.01), S. isronensis S0B8 (r = 0.75, p ≤ 0.01), and B. amyloliquefaciens S0B17 (r = 0.77, p ≤ 0.01) respectively. The P release kinetics followed the 1st order model well (R2 = 0.8001-0.8503). It seems that H+ ions and organic anions released from the organic acids are major factors responsible for RP solubilization. The SEM observations demonstrate that B. cereus S0B4 corroded the RP surface significantly due to the proton attack. The XRD analysis confirms that the intensity of all mineral peaks decreases after treatment with B. cereus S0B4. The FTIR analysis indicated a significant decrease of calcite and fluorapatite's vibrational bands with the disappearance of quartz.
- MeSH
- Bacteria MeSH
- fosfáty * chemie MeSH
- odpadní vody MeSH
- průmyslová hnojiva * MeSH
- půdní mikrobiologie MeSH
- Publikační typ
- časopisecké články MeSH
- Geografické názvy
- Indie MeSH
Plants form associations with different microbes; some promote their growth and protect from biotic and abiotic stresses in different ways. However, the biological role of fungi associated with the rhizosphere of medicinal plants is not well explored. In the present study, Colletotrichum gloeosporioides, and Aspergillus fumigatus isolated from the rhizosphere of Dillenia indica were screened for their phosphate solubilization and indole-3-acetic acid (IAA) production potential. The selected fungal strains were identified by macroscopic, microscopic, and molecular characteristics. Phosphate solubilization was qualitatively and quantitatively evaluated using Pikovskaya's (PVK) agar and PVK broth medium using different substrates such as AlPO4, Ca3(PO4)2, and FePO4. Colletotrichum gloeosporioides and Aspergillus fumigatus with respect to the phosphate source showed solubilization index (SI) of 1.7 ± 0.03 and 2.1 ± 0.04, and solubilized phosphate up to 138.8 ± 0.058 μg/mL and 121.6 ± 0.062 μg/mL. These fungal strains are also good producers of IAA and significantly enhance the growth of Vigna radiata and Cicer arietinum seedlings. This is the first report on A. fumigatus and C. gloeosporioides from the rhizosphere of Dillenia indica and their phosphate solubilization and IAA production ability.
A phosphate solubilizing fungus, Aspergillus awamori S29 was isolated from rhizoshpere of mungbean. The phosphate solubilizing activity of A. awamori S29 in liquid was 1,110 mg/L for tricalcium phosphate (TCP). The organism was able to solubilize various inorganic forms of phosphate at a wide range of temperatures. Among various insoluble phosphate sources tested, di-calcium phosphate was solubilized the most, followed by TCP. A. awamori S29 had significant effect (p < 0.05) on mungbean growth, total P and plant biomass under pot conditions, although no obvious difference in available P in soil and number of leaves was found compared to the control.
Functional diversity covers diverse functional traits of microorganisms in an ecosystem. Thus, we hypothesized that it could play an important role in the isolation of nitrogen-fixing and phosphate-solubilizing bacteria. These bacteria have been considered as biofertilizer for sustainable agriculture development. Soils were collected from different sites of agricultural field and performed several microbiological tests in which we observed considerable differences in heterotrophic microbial abundance and microbial activities among the microcosms. Functional diversity depends on both microbial richness and evenness. Based on the results of metabolic fingerprinting of the carbon sources of BiOLOG-ECO plates, richness and evenness was measured by determining Shannon diversity index and Gini coefficient, respectively. The results showed significant differences in both microbial richness and evenness, suggesting considerable variation of functional diversity among the microcosms. Thereafter, nitrogen-fixing and phosphate-solubilizing bacteria were isolated on Burk's and Pikovskaya media, respectively. The results revealed considerable variation of both types of bacterial abundance among the microcosms. Microcosm (T2) showing the highest functional diversity houses the maximum numbers of nitrogen-fixing and phosphate-solubilizing bacteria. Similarly, the microcosm (T5) exhibiting the lowest functional diversity houses the minimum numbers of nitrogen-fixing and phosphate-solubilizing bacteria. Thus, a strong positive correlation was observed between functional diversity and both types of bacterial abundance among the soil samples. Higher richness and evenness lead to the development of increased functional diversity that facilitates to accommodate substantial numbers of nitrogen-fixing and phosphate-solubilizing bacteria in soil. Taken together, the results demonstrated that functional diversity plays an important role in the isolation of nitrogen-fixing and phosphate-solubilizing bacteria from soil.
Mineral nutrition of crop plants is one of the major challenges faced by modern agriculture, particularly in arid and semi-arid regions. In alkaline calcareous soils, the availability of phosphorus and zinc is critically less due to their fixation and precipitation as complexes. Farmers use fertilizers to fulfill crop requirements, but their efficacy is less, which increases production costs. Plant growth-promoting rhizobacteria (PGPR) can improve the availability of crop nutrients through solubilizing the insoluble compounds of phosphorus and zinc in soil. In the present study, a total of 40 rhizobacterial isolates were isolated from cotton rhizosphere and screened for improving cotton growth through the solubilization of phosphorus and zinc. Out of these 40 isolates, seven isolates (IA2, IA3, IA6, IA7, IA8, IA13, and IA14) efficiently solubilized insoluble rock phosphate while seven isolates (IA10, IA16, IA20, IA23, IA24, IA28, and IA30) were more efficient in solubilizing insoluble zinc oxide. In liquid media, strain IA7 (2.75 μg/mL) solubilized the highest amount of phosphate while the highest concentration of soluble zinc was observed in the broth inoculated with strain IA20 (3.94 μg/mL). Seven phosphate-solubilizing and seven zinc-solubilizing strains were evaluated using jar trial to improve the growth of cotton seedlings, and the results were quite promising. All the inoculated treatments showed improvement in growth parameters in comparison with control. Best results were shown by the combined application of IA6 and IA16, followed by the combination of strains IA7 and IA20. Based on the jar trial, the selected isolates were further characterized by plant growth-promoting characters such as siderophores production, HCN production, ammonia production, and exopolysaccharides production. These strains were identified through 16S rRNA sequencing as Bacillus subtilis IA6 (accession # MN005922), Paenibacillus polymyxa IA7 (accession # MN005923), Bacillus sp. IA16 (accession # MN005924), and Bacillus aryabhattai IA20 (accession # MN005925). It is hence concluded that the integrated use of phosphate-solubilizing and zinc-solubilizing strains as potential inoculants can be a promising approach for improving cotton growth under semi-arid conditions.
- MeSH
- Bacillus klasifikace genetika izolace a purifikace metabolismus MeSH
- fosfáty metabolismus MeSH
- fosfor metabolismus MeSH
- fylogeneze MeSH
- Gossypium růst a vývoj mikrobiologie MeSH
- očkovadla agrotechnická klasifikace genetika izolace a purifikace metabolismus MeSH
- Paenibacillus polymyxa klasifikace genetika izolace a purifikace metabolismus MeSH
- půda chemie MeSH
- půdní mikrobiologie MeSH
- rhizosféra MeSH
- RNA ribozomální 16S genetika MeSH
- zinek metabolismus MeSH
- Publikační typ
- časopisecké články MeSH
