Mangrovibacter phragmitis sp. nov., an endophyte isolated from the roots of Phragmites karka

Abstract

A facultatively anaerobic, Gram-stain-negative, rod-shaped, nitrogen-fixing, endophytic bacterial strain designated MP23T was isolated from the roots of Phragmites karka growing in Chilika Lagoon, Odisha, India. Strain MP23T was slightly halophilic, and the optimal NaCl concentration and temperature for growth were 1 % and 30 °C, respectively. On the basis of 16S rRNA gene sequence similarities, strain MP23T was affiliated to the family Enterobacteriaceae and most closely related to Mangrovibacter yixingensis KCTC 42181T and Mangrovibacter plantisponsor DSM 19579T with 99.71 % similarity, followed by Salmonella enterica subsp. salamae DSM 9220T (97.22 %), Cronobacter condimenti LMG 26250T (97.14 %) and Salmonella enterica subsp. diarizonae DSM 14847T (97 %). Sequence analysis of 16S rRNA, hsp60, gyrB and rpoB genes showed that strain MP23T formed a phylogenetic cluster with M. yixingensis KCTC 42181T and M. plantisponsor DSM 19579T indicating that it belongs to the genus Mangrovibacter. The major cellular fatty acids were C16 : 0, C18 : 1ω6c and/or C18 : 1ω7c, C16 : 1ω6c and/or C16 : 1ω7c, C14 : 0, C14 : 0 3-OH and/or iso-C16 : 1 I and C17 : 0 cyclo. Polar lipids of strain MP23T consisted of phosphatidylglycerol, diphosphatidylglycerol and phosphatidylethanolamine. The DNA G+C content was 50.3 mol%. Based on experimental DNA-DNA hybridization values and average nucleotide identity derived from in silico comparison of whole-genome sequences, strain MP23T could be distinguished from its closest neighbours. We therefore conclude that strain MP23T represents a novel species of the genus Mangrovibacter for which the name Mangrovibacter phragmitis sp. nov. is proposed. The type strain is MP23T (=DSM 100250T=KCTC 42580T).