Induced Inorganic Phosphate Solubilization Through N-Methyl-N´-Nitro-N-Nitrosoguanidine Treated Mutants of Pseudomonas koreensis Strain AK-1 (MTCC Number 12058) Under Polyethylene Glycol

The excessive use of fertilizers in agriculture is mainly due to the recognized plant requirements for soluble phosphorus. This problem has limited the implementation of sustainable agriculture. A viable alternative is to use phosphate solubilizing soil microorganisms. This work aimed to isolate inorganic phosphorus-solubilizing bacteria from the soils of agroecosystems, to select and identify, based on sequencing and phylogenetic analysis of the 16S rRNA gene, the bacterium with the highest capacity for in vitro solubilization of inorganic phosphate. Additionally, we aimed to determine its primary phosphate solubilizing mechanisms and to evaluate its effect on Habanero pepper seedlings growth. A total of 21 bacterial strains were isolated by their activity on Pikovskaya agar. Of these, strain ITCB-09 exhibited the highest ability to solubilize inorganic phosphate (865.98 µg/mL) through the production of organic acids. This strain produced extracellular polymeric substances and siderophores that have ecological implications for phosphate solubilization. 16S rRNA gene sequence analysis revealed that strain ITCB-09 belongs to the genus Enterobacter. Enterobacter sp. ITCB-09, especially when immobilized in beads, had a positive effect on Capsicum chinense Jacq. seedling growth, indicating its potential as a biofertilizer.

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Influence of Salinity and pH on Inorganic Phosphate Solubilization by Bacteria of the Genus Burkholderia

10.12702/ii.inovagri.2014-a673 ◽

2014 ◽

Author(s):

J.A.T. Silva ◽

C.G.G. Santos ◽

F.G. Silva ◽

I.B. Santos ◽

M.B.G.S. Freire ◽

...

Keyword(s):

Inorganic Phosphate ◽

Phosphate Solubilization

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Evaluation of Inorganic Phosphate Solubilizing Efficiency and Multiple Plant Growth Promoting Properties of Endophytic Bacteria Isolated From Root Nodules Erythrina Brucei

10.21203/rs.3.rs-1079284/v1 ◽

2021 ◽

Author(s):

Belay Berza ◽

Jegan Sekar ◽

Prabavathy VR ◽

Marcela C Pagano ◽

Fassil Assefa

Keyword(s):

Bacillus Thuringiensis ◽

Inorganic Phosphate ◽

Phosphate Solubilization ◽

Root Nodules ◽

Achromobacter Xylosoxidans ◽

Bacterial Endophytes ◽

Plant Growth Promoting ◽

Growth Promoting ◽

Phosphate Solubilizing ◽

Acinetobacter Soli

Abstract Background: The majority of phosphorous in the soil is fixed and unavailable to plant nutrition, hence in scarcity. Phosphate solubilizing bacteria, the ecological engineers, are considered as the best, sustainable and eco-friendly options. The objectives of this study were to screen and evaluate inorganic phosphate solubilizing efficiency and assess multiple plant growth promoting traits of E. brucei root nodule bacterial endophytes.Results: A total of 304 nodule bacterial endophytes were screened for phosphate solubilization potential on solid PA medium among which 119 (39%) were potential tricalcium phosphate solubilizers. None of these isolates were able to form clearly visible halos on aluminum phosphate (AlPO4), Al-P or iron phosphate (FePO4), Fe-P supplemented PA medium. Out of 119 inorganic phosphate solubilizing endophytes, 40.3% were IAA producers. Based on phosphate solubilization index, the potential bacterial endophytes were identified to Gluconobacter cerinus, Acinetobacter soli, Achromobacter xylosoxidans and Bacillus thuringiensis using the 16S rRNA gene sequences analysis. All the selected isolates were potential solubilizers of the three inorganic phosphates (Al-P, Fe-P and tricalcium phosphate, TCP) included in liquid NBRIP medium. The highest values of solubilized TCP were recorded by isolates AU4 and RG6 (A. soli), 108.96 mg L-1 and 107.48 mg L-1, respectively at sampling day3 and 120.36 mg L-1 and 112.82 mg L-1, respectively at day 6. The highest values of solubilized Al-P and Fe-P were recorded by isolate RG6, 102.14 mg L-1 and 96.07 mg L-1, respectively at sampling days 3 and 6, respectively. The highest IAA, 313.61µg mL-1 was recorded by isolate DM17 (B. thuringiensis). These selected potential isolates were also HCN, NH3, and hydrolytic enzymes producers. The isolates were also varied in tolerance to eco-physiological stressors and exhibited versatility to carbon and nitrogen substrate utilization. Conclusions: The genera and species Gluconobacter cerinus, Acinetobacter soli, Achromobacter xylosoxidans and Bacillus thuringiensis are the first reports from E .brucei root nodules and Gluconobacter is also the first report to the science as phosphate solubilizer. Isolates AU4 and RG (A. soli) could be potential bio-inoculant candidates for the growth enhancement of the host plant for better agro-forestry practices in acidic and alkaline soils in Ethiopia.

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Inorganic phosphate solubilization by two Penicillium species in solution culture and soil

Soil Biology and Biochemistry ◽

10.1016/0038-0717(88)90058-2 ◽

1988 ◽

Vol 20 (4) ◽

pp. 459-464 ◽

Cited By ~ 197

Author(s):

P ASEA ◽

R KUCEY ◽

J STEWART

Keyword(s):

Inorganic Phosphate ◽

Phosphate Solubilization ◽

Solution Culture ◽

Penicillium Species

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Inorganic phosphate solubilization by rhizosphere bacteria in a Zostera marina community

Canadian Journal of Microbiology ◽

10.1139/m82-090 ◽

1982 ◽

Vol 28 (6) ◽

pp. 605-610 ◽

Cited By ~ 24

Author(s):

Pamela A. Craven ◽

Steven S. Hayasaka

Keyword(s):

Acetic Acid ◽

Calcium Phosphate ◽

Zostera Marina ◽

Inorganic Phosphate ◽

Phosphate Solubilization ◽

Dry Weight ◽

Rhizosphere Bacteria ◽

Bacterial Isolates ◽

Minimum Concentration ◽

Phosphate Solubilizing

Actively growing Zostera marina plants had a greater rhizosphere inorganic phosphate solubilizing potential than dormant plants. Rhizosphere bacteria that were capable of calcium phosphate solubilization were obligate aerobes and numbered approximately 4 × 108 colony-forming units/g dry weight root. Bacterial isolates solubilized calcium phosphate when cultured with glucose as the sole carbon and energy source but not when cultured with amino acids. Both calcium phosphate (hydroxyapatite) and glucose were found in sea grass bed sediment. Acetic acid was also detected from roots plus clinging sediment, from sediment, and from cultured bacterial isolates in a glucose-supplemented medium. The minimum concentration of acetic acid that showed detectable solubilization of calcium phosphate was 10−5 M. It is suggested that acetic acid, a product of glucose metabolism in the rhizosphere flora, is responsible for phosphate solubilization in the environment.

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Screening and optimization of indole-3-acetic acid production and phosphate solubilization by rhizobacterial strains isolated from Acacia cyanophylla root nodules and their effects on its plant growth

Journal of Genetic Engineering and Biotechnology ◽

10.1186/s43141-020-00090-2 ◽

2020 ◽

Vol 18 (1) ◽

Author(s):

Sara Lebrazi ◽

Karsten Niehaus ◽

Hanna Bednarz ◽

Mouhcine Fadil ◽

Marwa Chraibi ◽

...

Keyword(s):

Acetic Acid ◽

Plant Growth ◽

Inorganic Phosphate ◽

Phosphate Solubilization ◽

Crop Yields ◽

Root Nodules ◽

Iaa Production ◽

Acacia Cyanophylla ◽

Indole 3 Acetic Acid

Abstract Background Plant growth-promoting rhizobacteria (PGPR) are known to improve plant growth and are used as biofertilizers, thanks to their numerous benefits to agriculture such as phosphorus solubilization and phytohormone production. In this paper, four rhizospheric bacteria (Phyllobacterium sp., Bacillus sp., Agrobacterium sp., and Rhizobium sp.) isolated from surface-sterilized root nodules of Acacia cyanophylla were tested for their ability to solubilize inorganic phosphate and to produce indole-3-acetic acid (IAA) under laboratory conditions. Then, the best IAA producer (Rhizobium sp.) was selected to test optimized conditions for IAA production. Finally, the effect of the four strains on plant growth for A. cyanophylla was evaluated in vivo. Results The results showed that the totality of the tested isolates had solubilized inorganic phosphate (P) in both NBRIP (National Botanical Research Institute Phosphate) and PVK (Pikovskaya) media. Bacillus sp. was a high P-solubilizer and showed maximum solubilization in PVK (519 μg ml-1) and NBRIP (782 μg ml-1). The optimization of maximum phosphate solubilization was done using different sources of carbon (1%) and nitrogen (0.1%). Glucose and ammonium sulfate were selected to be the best carbon and nitrogen source for phosphate solubilization by all tested strains, except for Phyllobacterium sp., which recorded the highest phosphate solubilization with ammonium nitrate. The IAA production by the tested strains indicated that Rhizobium sp. produced the highest amount of IAA (90.21 μg ml-1) in culture media supplemented with L-tryptophan. The best production was observed with L-Trp concentration of 0.2% (116.42 μg ml-1) and at an initial pH of 9 (116.07 μg ml-1). The effect of NaCl on IAA production was tested at concentrations of 0 to 5% and the maximum production of 89.43 μg ml-1 was found at 2% NaCl. The extraction of crude IAA from this strain was done and purity was confirmed with Thin Layer Chromatography (TLC) analysis. A specific spot from the extracted IAA production was found to correspond with a standard spot of IAA with the same Rf value. Finally, the tested PGPR demonstrated growth stimulatory effects on Acacia cyanophylla seedlings in vivo, with a great increase of shoots’ and roots’ dry weights, and shoot length compared to control. The rhizobacterial isolates were identified by 16S rDNA sequence analysis as Agrobacterium sp. NA11001, Phyllobacterium sp. C65, Bacillus sp. CS14, and Rhizobium sp. V3E1. Conclusion This study highlights the importance of the use of phosphate solubilizing and IAA producer microorganisms as biofertilizers to increase crop yields. The studied strains showed a significant phosphate solubilization potential and IAA production. The use of selected strains as inoculants would be interesting, in particular with a view of promoting sustainable agriculture. However, further studies to verify the efficacy of the best isolates in situ is certainly required.

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