Isolation and identification of phosphate solubilizing bacteria from the rhizosphere of rice in organic and non-organic rice fields in Sukoharjo District, Indonesia

Abstract

Abstract. Purwanti D, Setyaningsih R, Susilowati A. 2019. Isolation and identification of phosphate solubilizing bacteria from the rhizosphere of rice in organic and non-organic rice fields in Sukoharjo District, Indonesia. Bonorowo Wetlands 9: 108-115. One of the essential nutrients in the soil is phosphate. Phosphate fertilization is often inefficient because phosphate is bound and difficult for plants to absorb. The use of phosphate solubilizing bacteria (PSB) can be used as an alternative to the availability of P in the soil. This study aimed to obtain PSB isolates with high phosphate solubilization ability and identify these PSB isolates molecularly. Soil samples were taken from organic and non-organic rice (Oryza sativa L.) fields in Sukoharjo, Central Java, Indonesia, namely Grogol Village, Menuran Village, and Pondok Village. The research activity was carried out in several stages: isolation of PSB on Pikovskaya medium, characterization and testing of PSB in dissolving P, and Gram staining. PSB colonies with a phosphate solubilization index and showed different colony colors were taken, and then DNA was isolated. DNA isolation was carried out by extraction method using a DNA extraction kit. The gene encoding 16S rRNA amplified the obtained DNA samples. Sequencing was carried out using a genetic analyzer. Data analysis by comparing sequence data on the BLASTN program. Based on the isolation of rhizosphere samples from organic paddy fields, 14 isolates of PSB were obtained, and ten isolates of non-organic paddy were PSB. P13, P1, Q7, and Q8 isolates had the highest P solubilization ability with dissolution index (IP), namely 3.35, 2.13, 1.82, and 1.47. The 16S rRNA gene sequence analysis showed that isolates P1 and P13 had 99% similarity to Acinetobacter sp. ADP1 strain. The isolate Q7 had a 96% similarity with the genus Clavibacter strain NCPPB 382, ??while Q8 had a 99% similarity with Pseudomonas aeruginosa strain PAO1.