Rheinheimera hassiensis sp. nov. and Rheinheimera muenzenbergensis sp. nov., two species from the rhizosphere of Hordeum secalinum

Abstract

Two motile, Gram-staining-negative, aerobic, rod-shaped bacteria designated strains E48(T) and E49(T) were isolated from the rhizosphere of Hordeum secalinum from a natural salt meadow near Münzenberg, Germany. 16S rRNA gene sequence similarity analysis revealed that strains E48(T) and E49(T) shared similarities of 97.6 % with Rheinheimera pacifica KMM 1406(T) and 98.5 % with Rheinheimera nanhaiensis E407-8(T), respectively. Major fatty acids of strain E48(T) were C16 : 0, summed feature 3 (C16 : 1ω7c and/or iso-C15 : 0 2-OH) and C17 : 1ω8c, and of strain E49(T) were C16 : 0, summed feature 3 (C16 : 1ω7c and/or iso-C15 : 0 2-OH) and C18 : 1ω7c. The DNA G+C contents were 50.5 mol% (E48(T)) and 50.0 mol% (E49(T)). Strains E48(T) and E49(T) grew at 4-37 °C (optimum 28 °C) and with 0-6 % NaCl (optimum 0-3 %) and 0-5 % NaCl (optimum 0-3 %), respectively. The potential for nitrogen fixation by strains E48(T) and E49(T) was evaluated by molecular techniques and the acetylene reduction assay. The DNA-DNA hybridization, physiological and molecular data demonstrated that strains E48(T) and E49(T) represent two novel species of the genus Rheinheimera, and therefore the names Rheinheimera hassiensis sp. nov. (type strain E48(T) = LMG 27268(T) = KACC 17070(T)) and Rheinheimera muenzenbergensis sp. nov. (type strain E49(T) = LMG 27269(T) = KACC 17071(T)) are proposed.