Preliminary Study on the Bacterial Community Structure of Ganoderma Soil Under Oil Palm Plantation

Basal stem rot (BSR) disease is caused by Ganoderma boninense ; it has become a major disease in oil palm plantations over the years and causes a significant yield drop in oil palm plantations, especially in Sumatera. Nowadays, the incidence level of BSR across Sumatera has reached 39% and is predicted to keep increasing and threatening the sustainability of oil palm plantations between 2050 and 2100. Some researchers believe that Ganoderma is dominant due to the unbalance of the microbial community in the soil ecosystem. This study aims to discover the bacterial community structure in the soil under Ganoderma boninense infection in oil palm plantations. The study was conducted by comparing the soil infected by Ganoderma boninense (G+) and the healthy soil (G) through the next-generation sequencing (NGS) by Illumina MiSeq. The study shows that the total bacteria of the healthy soil (G) was 177 times higher than the endemic soil with a total copy number 1.32x10 8 and 7.44x10 5 , respectively. Acidobacteria was the dominant phyla in the healthy soil (G), followed by Proteobacteria, and their relative abundance are 31.45% and 29.19%, respectively. On the other hand, the relative abundance of Acidobacteria in the endemic soil (G+) was decreased to 18.73% while Proteobacteria was increased to 38.34%. However, the abundance of these phyla in the endemic soil (G+) is still lower than in the healthy soil (G). At the level species, the healthy soil (G) was more diverse than the endemic soil (G+). It shows that the endemic soil is more susceptible to Ganoderma boninense due to its dominance in the soil ecosystems. The 16S rRNA gene sequencing revealed that more than 60% of OTUs had <98% of similarity. It is indicated that some species, both in healthy soil (G) and endemic soil (G+), under oil palm plantations might be novel species.