Metagenomic and Culture-Dependent Analysis of the Bacterial Diversity of a Hot Spring Reservoir as a Function of the Seasonal Variation

Abstract

A natural thermal habitat, Tulasi Shyam, was studied for the culture-dependent and culture-independent diversity of the thermophilic bacteria. Soil and water samples of winter, summer and monsoon seasons were analyzed to assess the impact of the seasonal variation on the microbial diversity. The soil was fertile and contained high humic substances. The temperature of the water was 50 °C, which did not significantly vary with seasons. Various methods were assessed for the extraction of the metagenomic DNA to obtain quality DNA in good quantity. The 16S rRNA genes were amplified using the metagenomic DNA as template and the products were analyzed further by the denaturing gradient gel electrophoresis (DGGE) for evaluating the bacterial diversity. The metagenomic diversity of the hot spring reservoir-1 as compared to reservoir-2 was less influenced by the seasonal variations. The DGGE patterns of the soil samples suggested significant effect of the seasonal changes. The metagenomic diversity was distinct when compared with the culture-dependent microbial diversity. The diversity was further analyzed by the principal component analysis (PCA) and diversity indices. The apparent shift in the diversity appears to be governed by the prevailing environmental conditions.