Comparative Analysis of 16S rRNA Gene Illumina Sequence for Microbial Community Structure in Diverse Unexplored Hot Springs of Odisha, India

Odisha (East India) is home to several hot springs, of which Atri and Taptapani are the two with variation in temperature and located in the Mahanadi geothermal province having altitude 120 and 1800ft., respectively, above sea level. Average temperature of Atri hot spring is as higher as 58 +/- 5 degrees C as compared to 48 +/- 5 degrees C of Taptapani. In-depth analysis of the microbial diversity of these hot springs through 16S rRNA deep sequencing analysis, targeting V3 region was performed using Illumina bar-coded sequencing platform. Existence of higher microbial diversity in Atri hot spring (1662 OTUs; 2708 species) as compared to Taptapani (1561 Operational Taxonomic Units [OTUs]; 2045 species) is supported by higher value of diversity indices for Atri (6.24, Shannon; 0.95, Simpson) than Taptapani (4.03, Shannon; 0.79, Simpson), probably due to favorable influence of environmental parameters around it. Irrespective of the four databases (GREENGENE, M5RNA, Ribosomal Database Project [RDP], and Small Subunit [SSU] databases) used for understanding community structure, the dominant phyla in the Atri hot spring were different from the predominant populations in the Taptapani in terms of percentage representation in different databases. From Principal Coordinates Analysis [PCoA] analysis, Atri and Taptapani metagenome, on comparison with other three metagenomes, were found to be matching with the community structure of hot springs of Gujarat, India, but differed from that of saline desert. Furthermore, predicted functional analysis in both the hot springs were found to be affiliated with carbohydrate, amino acids, energy, vitamins and cofactor, nucleotide, membrane transport metabolic pathways, and the genes involved in them, although their intensity of occurrence was varying as analyzed through PICRUSt and Tax4Fun probably due to physicochemical parameters prevailing around each hot spring. The present study for the first time has revealed the differential microbial community structure and predicted functional diversity of Atri and Taptapani hot springs of Odisha in such a great detail.