Environmental factors influencing the distribution of rRNA from Verrucomicrobia in soil.

The Verrucomicrobia constitute a newly discovered division of the Bacteria identified as a numerically abundant component of soil microbial communities in numerous sites around the world. The relative abundance of rRNA from Verrucomicrobia was investigated in the soil to examine the influence of specific environmental factors on the distribution of Verrucomicrobia and to better understand the distribution of this group in terrestrial ecosystems. The abundance of the verrucomicrobial rRNA was determined by using a novel oligonucleotide probe that is specific for verrucomicrobial 16S rRNA. The abundance of verrucomicrobial 16S rRNA in soil microbial communities was determined in relation to plant community composition and soil management history over a period of 2 years. Additional samples were analyzed to determine if verrucomicrobial rRNA relative abundance changes in relation to either soil depth or soil moisture content. The Verrucomicrobia composed 1.9+/-0.2% of the microbial community rRNA present in the 85 soil samples examined. The distribution of verrucomicrobial rRNA in the soil reveals that Verrucomicrobia are significantly affected by environmental characteristics that change in relation to time, soil history, and soil depth, and reveals that a statistically significant amount of the variation in verrucomicrobial rRNA abundance can be explained by changes in soil moisture content.