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Abstract
The goal of this study was to investigate and establish the number of bacterial taxa and their relative abundance within soil microbial communities in various natural east Texas habitats. An aim of this research was the addition of bacteria to an existing ecological classification system recently developed for the West Gulf Coastal Plain by Van Kley et al. (2007). Bacterial diversity was determined by genetic fingerprinting techniques using PCR-DGGE and pyrosequencing of ∼200 base pair fragments of 16S rRNA from bacteria. Twenty nine DGGE profiles were obtained and statistical analysis revealed significant diversity in bacterial community composition with noticeable preferences of taxa for the river floodplain based on the availability of sulfur. Pyrosequencing of 16S rDNA obtained a total of 42,151 sequences from five environmental soil samples and quantitatively confirmed bacterial richness and distribution. Statistical analysis of sequencing data verified the relationship of bacterial community composition to habitat type supported by increased values in sulfur, clay, and magnesium observed in the river floodplains. Taxonomic identification of bacteria by comparative sequence analysis was achieved using BLAST and RDP Classifier. The majority of bacterial taxa predominantly belong to the phylum Proteobacteria, followed by Actinobacteria, Acidobacteria, Chloroflexi, Verrucomicrobia, Firmicutes, Nitrospira, and Planctomycetes. The results of this study showed that PCR-DGGE and pyrosequencing methods are adequate in surveying bacterial diversity from environmental soil samples and that bacterial community composition can be used as an additional factor in ecological classification of east Texas habitats.
