High-Throughput Sequencing-Based Review of Bacillus Diversity in Jordanian Hot Springs Water

: Bacillus or Bacillus-related genera were the most frequently documented isolates from Jordanian hot springs in several earlier studies based on culture-dependent methods. This study aimed to review the abundance and composition of the genus Bacillus in Jordanian hot springs (Ma'in and Afra springs) using a culture-independent approach by Illumina MiSeq. The studied samples included three samples from Ma'in hot springs (HS1, HS2 and HS3) and one sample from Afra hot springs (HS4). Relative to the domain Bacteria, the abundance of Bacillus was found to be very low: 2% (in HS1), 3% (in HS2), 0.5% (in HS3) and 1% (in HS4). However, the abundance in lower taxonomic ranks was found to be higher: at the level of phylum Firmicutes, the genus constitutes 7% in HS1, 41% in HS2, 31% in HS3 and 33% in HS4. Bacillus was found to dominate the order Bacillales and class Bacilli only in case of HS2 (64%). In case of HS1, HS3 and HS4, the abundance was 18, 47 and 39%, respectively. Finally, Bacillus was found to be dominant as compared to other genera within the family Bacillaceae in case of HS2 (84%), HS3 (77%) and HS4 (61%) but not in HS1 (22%) which was dominated by the genus Anoxybacillus (77%). In respect to genus composition, in all studied hot springs, the species B. firmus was found the dominant species. Nevertheless, other species with lesser abundances were also detected like B. cereus, B. beringensis, B. weihenstephanensis, B. funiculus and B. Oceanisediminis.