Comparative Genomic Analysis of a Novel Strain of Taiwan Hot-Spring Cyanobacterium sp. CL-1.

is a genus of thermophilic unicellular cyanobacteria that are dominant in microbial mats at about 50-65°C in alkaline hot springs of eastern Asia. We used PacBio SMRT Sequencing to sequence the complete genome of a novel strain of thermophilic cyanobacterium, sp. CL-1, isolated from the Chin-Lun hot spring (pH 9.3, 62°C) in Taiwan. Genome-scale phylogenetic analysis and average nucleotide identity (ANI) results suggested that CL-1 is a new species in the genus . Comparative genome analysis revealed divergent genome structures of strains. In addition, the distinct genetic differences between CL-1 and the other strains are related to photosynthesis, transporters, signal transduction, the chaperone/usher system, nitric oxide protection, antibiotic resistance, prokaryotic immunity systems, and other physiological processes. This study suggests that strains have actively acquired many putative horizontally transferred genes from other bacteria that enabled them to adapt to different ecological niches and stressful conditions in hot springs.