Soil bacterial community structure associated with oil palm (Elaeis guineensis) fatal yellowing disease

Brazilian biodiesel is mainly produced from soybean oil produced at low yields. Oil palm (Elaeis guineensis) can produce 3 to 5 tons of oil/ha. These high oil yields are however threatened by Fatal Yellowing (FY), which starts with yellowing of leaflets and spear, followed by wilt, necrosis and plant death. The causal agent of FY is still unknown. Reports suggesting that FY might be transmitted through soil and that soil microbial communities can influence plant health prompted this work to compare the soil bacterial communities associated with healthy oil palm trees and those showing symptoms of FY. Pyrosequencing of the 16S rDNA generated ~500,000 good-quality sequences from soil bacterial communities of healthy (stage 0) and FY diseased plants (stages 5 and 8) to be analyzed. The most abundant phylum considering all stages studied was Acidobacteria (44.6%). A greater number of OTUs was observed at FY stage 5 followed by FY stage 8 and stage 0 healthy plants. Beta-diversity analysis showed that the bacterial communities in the three different stages studied are significantly different. Stamp analysis showed that rare phyla are more abundant in soils of FY stage 5 and stage 8 plants. Root rot in trees affected by AF may help to explain the higher diversity of rare phyla at FY stages 5 and 8. Although a specific possible causal agent for FY was not identified, this is the first report of the composition and structure of soil bacterial communities associated with AF using high-throughput sequencing.