Rheinheimera tangshanensis sp. nov., a rice root-associated bacterium.

A Gram-negative, aerobic, rod-shaped bacterium, designated strain JA3-B52(T), was isolated from the roots of fresh rice plants (Oryza sativa). The cells were motile by means of polar single or lateral flagella. The colonies were non-pigmented. On the basis of 16S rRNA gene sequence comparisons, the strain was phylogenetically related to species of the genus Rheinheimera, having the greatest level of sequence similarity with respect to Rheinheimera texasensis A62-14B(T) (97.16 %). The bacterium grew at temperatures from 10 to 37 degrees C, with an optimum at 30 degrees C. The strain exhibited growth with 0-3.0 % (w/v) NaCl and at pH 6.0-8.5. The main cellular fatty acids were C(16 : 1)omega7c, C(17 : 1)omega8c, C (16 : 0), C(18 : 1)omega7c and C(12 : 0) 3-OH. The DNA G+C content was 47.0 mol%. The levels of similarity between the 16S rRNA gene sequence of strain JA3-B52(T) and those of the type strains of Rheinheimera species ranged from 95.38 to 97.16 %. The mean level of DNA-DNA relatedness between strain JA3-B52(T) and R. texasensis A62-14B(T), the strain most closely related to the isolate, was 20.4 %. On the basis of physiological and biochemical characteristics and genotypic data obtained in this work, strain JA3-B52(T) represents a novel species of the genus Rheinheimera, for which the name Rheinheimera tangshanensis sp. nov. is proposed. The type strain is JA3-B52(T) (=CGMCC 1.6362(T) =DSM 19460(T)).