The Influence of Different Acidic Conditions on the Plant Growth-Promoting Rhizobacteria Activity of Phosphate Solubilizing Bacteria
The acidity of the soil influences the amount of phosphorus available in the soil; acidic soils have low phosphorus availability. The use of phosphorus solubilizing bacteria improves phosphorus availability in acidic soils. The production of dissolved phosphorus and organic acids is one of the functions of the plant growth-promoting rhizobacteria (PGPR) activity of phosphorus solubilizing bacteria. The purpose of this study was to examine how acidity affects the organic acid production and dissolved phosphorus levels of phosphate solubilizing bacteria. Experiments were carried out in the Laboratory of Soil Biology, Department of Soil and Land Resources, Faculty of Agriculture, Universitas Padjadjaran. Two isolates of PGPR (Burkholderia sp. strain WK 11 and Burkholderia sp. strain MQ-14W) were used in this study, both of which were isolated from an acidic soil-ecosystem. pH 4.5, normal pH (7) and 10.5 were the levels of acidity. The results revealed that the acidity of the water had an effect on the amount of dissolved phosphorus and the amount of organic acid produced by the phosphate solubilizing bacteria. PSB produced more organic acid (lactic, citric, oxalic, and tartaric acid) and dissolved phosphorus at pH 4.5 than at pH 7 or pH 10.5.
Keywords: Acidity, Burkholderia, organic acid, PGPR, solubilizing P
 López-Arredondo DL, Leyva-González MA, González-Morales SI, López-Bucio J, Herrera-Estrella L. Phosphate nutrition: Improving low-phosphate tolerance in crops. Ann. Rev. Plant Biol. 2014; 65: 95–123.
 Hanyabui E, Apori SO, Frimpong KE, Atiah K, Abindaw T, Ali M, Asiamah JY, Byalebeka J. Phosphorus sorption in tropical soils. AIMS Agriculture and Food. 2020;5(4):599-616.
 Penn CJ, Camberato JJ. A critical review on soil chemical processes that control how soil pH affects phosphorus availability to plants. Agriculture. 2019;9:120.
 Havlin JL, Beaton JD, Tisdale SL, Nelson WL. Soil fertility and fertilizers. 6th ed. New Jersey: Pearson Prentice Hall; 2005.
 Cerozi BDS, Fitzsimmons K. The effect of pH on phosphorus availability and speciation in an aquaponics nutrient solution. Bioresource Technology. 2016;219:778-781.
 Tian J, Ge F, Zhang D, Deng S, Liu X. Roles of phosphate solubilizing microorganisms from managing soil phosphorus deficiency to mediating biogeochemical P cycle. Biology. 2021;10:158.
 Serna-Posso EJ, Prager MS, Cisneros-Rojas CA. Organic acids production by rhizosphere microorganisms isolated from a typic melanudands and its effects on the inorganic phosphates solubilization. Acta Agronómica. 2017;66(2):241-247
 Pande A, Pandey P, Mehra S, Singh M, Kaushik S. Phenotypic and genotypic characterization of phosphate solubilizing bacteria and their efficiency on the growth of maize. Journal of Genetic Engineering and Biotechnology. 2017;15:379-391.
 Barker AV, Pilbeam DJ. Hand book of plant nutrition. New York: CRC Press; 2007.
 Beebout SEJ, Loeppert RH. Role of organic acids in phosphate mobilization from iron oxide. Soil Science Society of America Journal. 2006;70(1):222-234.
 Li Z, Bai T, Dai L et al. A study of organic acid production in contrasts between two phosphate solubilizing fungi: Penicillium oxalicum and Aspergillus niger. Scientific Reports. 2016;6:25313.
 Stanaszek-Tomal E. Environmental factors causing the development of microorganisms on the surfaces of national cultural monuments made of mineral building materials—Review. Coatings. 2020;10:1203.
 Sheu SY, Chou JH, Bontemps C et al. Burkholderia diazotrophica sp. nov., isolated from root nodules of Mimosa spp. International Journal of Systematic and Evolutionary Microbiology. 2013;63(2):435-441.
 Jones DL, Brassington DS. Sorption of organic acid in acid soils and its implications in the rhizosphere. Eur. J. Soil Sci. 1998;49:447-455.
 Adeleke R, Nwangburuka C, Oboirien B. Origins, roles and fate of organic acids in soils: A review. South African Journal of Botany. 2017;108:393-406.