Analysis of peat bacterial diversity in oil palm plantations and a logged forest in Jambi, Indonesia, using PCR-DGGE technique

Abstract

Jambi Province has around 617,000 hectares of peatlands spread across six districts, including Tanjung Jabung Timur. Reports on microbial diversity under different land cover, especially those using molecular techniques, were very limited. The study aimed to evaluate the impact of peatlands conversion on soil bacterial biodiversity, through the analysis of 16S-rDNA gene employing polymerase chain reaction combined with denaturing gradient gel electrophoresis (PCR-DGGE). Peat soil samples were taken from the topsoil (rhizosphere) of 3 sites, i.e. (A) conventional drained (50 to 70 cm) oil palm plantation, (B) shallow drained (30 to 50 cm) oil palm plantation, and (C) logged-over peat forest. Sequential analysis based on the 16S rRNA gene showed that 15 operational taxonomic units (OTUs) could be grouped into 3 phyla, namely Proteobacteria, Acidobacteria, and Actinobacteria. The alignment result of nucleotide shows that 4 of 15 bands of DGGE were identified as the uncultured bacterium (Sulfurospirillum, Acidobacteria, Rhodoplane, and Magnetospirillum). Overall, the Shannon-Weaver biodiversity index showed that the conversion of peatlands to oil palm plantation increased bacterial biodiversity. This could be attributed to drainage, ferlilization, and biomass inputs under the oil palm plantations. The higher biodiversity under oil palm plantations also implies a higher rate of peat decomposition under this land use, relative to the forest.