Thermus parvatiensis RL(T) sp. nov., Isolated from a Hot Water Spring, Located Atop the Himalayan Ranges at Manikaran, India.

Abstract

A Gram negative, yellow pigmented, rod shaped bacterium designated as RL(T) was isolated from a hot water spring (90-98°C) located at Manikaran in Northern India. The isolate grows at 60-80°C (optimum, 70°C) and at pH 7.0-9.0 (optimum pH 7.2). Phylogenetic analysis of 16S rRNA gene sequences and levels of DNA-DNA relatedness together indicate that the new isolate represents a novel species of the genus Thermus with closest affinity to Thermus thermophilus HB8(T) (99.5%) followed by Thermus arciformis (96.4%). A comparative analysis of partial sequences of housekeeping genes (HKG) further revealed that strain RL(T) is a novel species belonging to the genus Thermus. The melting G+C content of strain RL(T) was calculated as 68.7mol%. The DNA-DNA relatedness value of strain RL(T) with its nearest neighbours (>97%) was found to be less than 70% indicating that strain RL(T) represents a novel species of the genus Thermus. MK-8 was the predominant respiratory quinone. The presence of characteristic phospholipid and glycolipid further confirmed that strain RL(T) belongs to the genus Thermus. The predominant fatty acids of strain RL(T) were iso-C17:0 (23.67%) and iso-C15:0 (24.50%). The results obtained after DNA-DNA hybridization, biochemical and physiological tests clearly distinguished strain RL(T) from its closely related species. Thus, strain RL(T) represents a novel species of the genus Thermus for which the name Thermus parvatiensis is proposed (=DSM 21745(T)= MTCC 8932(T)).