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

Abstract

A Gram-staining-negative, non-spore-forming endophytic bacterium, designated strain YC6887T, 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 YC6887T 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 °C (optimum 28-30 °C) and at pH 5.0-9.0 (optimum pH 7.0-8.5). Strain YC6887T 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 YC6887T and M. mediterranea MACL11T was 19.8±6.8. Chemotaxonomically, strain YC6887T contained C19: 0 cyclo ω8c (28.0 %) and C18: 1ω7c (17.9 %) as predominant fatty acids, confirming the affiliation of strain YC6887T 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 YC6887T 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 YC6887T (= KCCM 43011T = NBRC 109149T). © 2013 IUMS.