Martelella endophytica sp nov., an antifungal bacterium associated with a halophyte

A Gram-staining-negative, non-spore-forming endophytic bacterium, designated strain YC6887(T), was isolated from a root sample of a halophyte, Rosa rugosa, collected from a tidal flat area of Namhae Island, located at the southern end of Korea. Strain YC6887(T) was found to exhibit inhibitory activity against oomycete plant pathogens. The cells were non-motile and aerobic rods. The strain was able to grow at 4-40 degrees C (optimum 28-30 degrees C) and at pH 5.0-9.0 (optimum pH 7.0-8.5). Strain Y06887(T) was able to grow at NaCl concentrations of 0-9% (w/v) with optimum growth at 4-5% (w/v) NaCl, but NaCl is not essential for growth. Comparison of 16S rRNA gene sequences showed that the strain was a member of the genus Martelella, a member of order Rhizobiales, exhibiting highest similarity with Martelella mediterranea (98.6%). The DNA-DNA relatedness between strain YC6887(T) and M. mediterranea MACL11(T) was 19.8 +/- 6.8. Chemotaxonomically, strain YC6887(T) contained C-19:0 cyclo omega 8c (28.0%) and C(18:)1 omega 7c (17.9%) as predominant fatty acids, confirming the affiliation of strain YC6887(T) with the genus Martelella. The major respiratory quinone was Q-10 and the DNA G C content was 62.1 mol%. On the basis of phylogenetic analysis, physiological and biochemical characterization and DNA-DNA hybridization data, strain YC6887(T) should be classified as representing a novel species of the genus Martelella, for which the name Martelella endophytica sp. nov. is proposed. The type strain is YC6887(T) (=KCCM 43011(T)=NBRC 109149(T)).