Isolation and selection of highly effective phosphate solubilizing bacterial strains to promote wheat growth in Egyptian calcareous soils

Abstract

Background: Forty phosphate solubilizing bacterial (PSB) isolates were isolated from the root zone of wheat plants cultivated in the Delta and the Northwestern coast regions of Egypt. All isolates proofed their ability to dissolve tricalcium phosphate on the National Botanical Research Institute's phosphate growth medium (NBRIP) by producing clear zone and increasing the available phosphorus that ranged between 40 and 707 mg l −1. They were designated as Egyptian native phosphate solubilizing bacteria (ENPSB). Results: All strains proofed their ability to dissolve tricalcium phosphate on (NBRIP) medium by producing clear zone and increasing the available phosphorus that ranged between 40 and 707 mg l −1. The ENPSB 1, 2, and 3 strains were highly efficient as they gave 707, 653, and 693 mg l −1 soluble phosphorus respectively. Intriguingly, the two highly efficient strains for phosphate solubilization were isolated from the Northwestern coast alkaline soils. Moreover, 75% of strains were also produced profitable amounts of indole acetic acid (IAA) ranged from 0.79 to 50.5 mg l −1. Amazingly, the most efficient strain ENPSB 1 in solubilizing phosphorus (707 mg l −1 soluble P) was the best one for producing IAA (50.5 mg l −1). The three efficient strains were identified using the sequencing of 16S rRNA. Sequence analysis of 16S rRNA for selected strains confirmed that the strains ENPSB 1, 2, and 3 were genetically closed to Enterobacter aerogenes; Pantoea sp. and Enteriobacter sp. respectively. Conclusion: The inoculation by mix cultures of strains (ENPSB 1, 2, and 3) contributed to raising the dry weight and P content of wheat plants by 76% and 12% over the full fertilized plants. Inoculation of soil PSB can be used to solve the deficiency of phosphorus and promote plant growth effectively in calcareous soils.

Plant growth‐promoting and antibacterial activities of cultivable bacteria alive in tobacco field against Ralstonia solanacearum

“…We firstly reported new PGPB species such as Bosea minatitlanensis SSB‐9, Ralstonia pickettii SSB‐24 and Mitsuaria chitosanitabida SSG‐13 that had plant growth‐promoting activities. The amount of IAA produced by bacterial strains in the present study is comparable to other PGPB reported in the literatures (Suleman et al ., 2018; Mohamed et al ., 2019). Some strains produced higher concentration of IAA than the same species in other reports.…”

Isolation, identification, and characterization of phosphate solubilizing bacteria, Paenibacillus sp., from the soil of Danum Valley Tropical Rainforest, Sabah, Malaysia

“…The screening and isolation of PSB were done based on the procedures done by Nautiyal (1999) and Mohamed et al (2019). Firstly, the 5g of soil was suspended with 20ml of autoclaved MiliQ water and was agitated for 1hour at 30ºC.…”

Molecular Characterization and Mineralizing Potential of Phosphorus Solubilizing Bacteria Colonizing Common Bean (Phaseolus vulgaris L.) Rhizosphere in Western Kenya

“…A droplet of liquid in diluents in the test tubes was placed on the midpoint of the sterile agar plate and uniformly spread across the surface with the help of a sterilized glass-rod and incubated for fve days at 28 °C. Subculturing was carried out to obtain the pure isolates [26].…”

“…Certifed bean seeds were surface sterilized with 1% mercuric chloride for 3 minutes followed by rinsing with distilled water and pregermination in a darkroom using Petri dishes. Inoculants were prepared according to [26]. Te isolates were grown in NBRIB broth for 2 days and cells were harvested by centrifugation at 5000 × g for 20 min.…”