Determination of the Plant Growth-Promoting Rhizobacteria of Certain Bacterial Strains and Species Identification Using Molecular Analysis Methods
Sustainability in agriculture depends on the protection and continuity of natural resources. The reduction of inorganic fertilizer use in agriculture plays a significant role in the conservation of soil and water resources. The presence of existing bacteria in the soil tends to decline due to environmental factors such as temperature, pH, moisture, and others. The intensive use of systemic pesticides causes the elimination of beneficial organisms in the soil. The success of biological nitrogen fixation, as well as phosphorus and potassium solubilization, depends on the presence of sufficient numbers of effective bacterial strains in the plant growth environment. Plant Growth-Promoting Rhizobacteria (PGPR) are defined as bacteria that colonize the rhizosphere — the region surrounding the plant roots in the soil. These bacteria have multiple direct and indirect beneficial effects on plants. They directly affect plants by making nutrient elements available for plant uptake, fixing free atmospheric nitrogen, solubilizing phosphates, and increasing the plant's water-holding capacity. Indirectly, they suppress pathogenic microorganisms through the production of secondary metabolites such as antibiotics and siderophores, competition for space and nutrients, and the enhancement of systemic resistance. In the study by Karaca, M. S. (2018), bacteria were isolated from soil samples collected from the rhizosphere regions of cereal crops in Konya and Karaman provinces. Among these bacteria, 20 isolates were tested in this project for their nitrogen fixation, phosphorus solubilization, and potassium solubilization abilities under in vitro conditions. As a result, 10 bacteria with high nutrient-solubilizing potential were selected for genetic identification. It was determined that 4 isolates belonged to the species Bacillus halotolerans and 6 isolates belonged to the species Bacillus velezensis
Sustainability in agriculture depends on the protection and continuity of natural resources. The reduction of inorganic fertilizer use in agriculture plays a significant role in the conservation of soil and water resources. The presence of existing bacteria in the soil tends to decline due to environmental factors such as temperature, pH, moisture, and others. The intensive use of systemic pesticides causes the elimination of beneficial organisms in the soil. The success of biological nitrogen fixation, as well as phosphorus and potassium solubilization, depends on the presence of sufficient numbers of effective bacterial strains in the plant growth environment. Plant Growth-Promoting Rhizobacteria (PGPR) are defined as bacteria that colonize the rhizosphere — the region surrounding the plant roots in the soil. These bacteria have multiple direct and indirect beneficial effects on plants. They directly affect plants by making nutrient elements available for plant uptake, fixing free atmospheric nitrogen, solubilizing phosphates, and increasing the plant's water-holding capacity. Indirectly, they suppress pathogenic microorganisms through the production of secondary metabolites such as antibiotics and siderophores, competition for space and nutrients, and the enhancement of systemic resistance. In the study by Karaca, M. S. (2018), bacteria were isolated from soil samples collected from the rhizosphere regions of cereal crops in Konya and Karaman provinces. Among these bacteria, 20 isolates were tested in this project for their nitrogen fixation, phosphorus solubilization, and potassium solubilization abilities under in vitro conditions. As a result, 10 bacteria with high nutrient-solubilizing potential were selected for genetic identification. It was determined that 4 isolates belonged to the species Bacillus halotolerans and 6 isolates belonged to the species Bacillus velezensis
Mehmet Sait Karaca