Impact of oil palm fatal yellowing on Amazon soil archaeal community assessed by high-throughput sequencing

In Brazil, one of the most promising feedstocks for biodiesel production is oil palm oil, both for its superior productivity and oil quality. However, little is known about the oil palm soil archaeal communities, especially in relation to Fatal Yellowing (FY), a disease of unknown etiologic agent that affects oil palms in the Amazon region of Brazil. This study aimed to compare soil archaeal communities of oil palm plants with and without FY symptoms using high-throughput sequencing of the 16S ribosomal RNA gene. Nine soil samples grouped according to disease stage (0, 5 and 8) were studied. All 16S rRNA reads were analyzed by Mothur for quality control and taxonomic classifications. Archaeal taxonomic classifications were performed based on SILVA database (release 119). All soils, regardless of disease stage, show only two archaeal phyla, Euryarchaeota and Thaumarchaeota. Euryarchaeota was the main phylum in all samples, with significant higher representation in soils with Group 8 plants, the most advanced disease stage. Soil from Group 8 plants had higher archaeal diversity (richness and abundance), with the highest number of OTUs observed. A higher representation of the classes South African Gold Mine Gp1 (Thaumarchaeota) and Thermoplasmata (Euryarchaeota) correlated with increasing FY symptoms. Hitherto, there are no reports of pathogenic Archaea. However, this study found an increase in the overall archaeal diversity as well as an increase in abundance of some archaeal classes correlated with FY. Further studies are needed to identify the roles of these archaeal communities in both plant health and plant disease.