Umezawaea endophytica sp. nov., isolated from tobacco root samples

Abstract

Two Gram-staining positive, aerobic and non-motile actinomycete strains, designated YIM 2047XT and YIM 2047D, were isolated from tobacco root samples collected from Shiling county, Yunnan province, South-West China. The isolates grew at 15–40 °C, pH 6.0–8.0 and 0–4.5 % NaCl (w/v). The whole-cell hydrolysates contained meso-diaminopimelic acid, galactose, mannose, ribose and rhamnose. The polar lipids detected were diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylmethylethanolamine, phosphatidylinositol and phosphatidylinositol mannoside. The major cellar fatty acids identified were iso-C14:0, iso-C15:0, anteiso-C15:0, iso-C16:0, C16:0, C17:1 ω8c and C17:0. MK-9 (H4) was the predominant menaquinone. The genomic DNA G+C contents were 73.4 and 74.2 mol%, respectively. These chemotaxonomic data, together with their morphological properties, were consistent with the assignment of the two strains to the genus Umezawaea. They showed highest similarities to Umezawaea tangerina JCM 10302T on phylogenetic analysis of their 16S rRNA gene sequences and were found to form a coherent cluster. However, the DNA–DNA hybridization values of YIM 2047XT and YIM 2047D with U. tangerina JCM 10302T were 46.5 ± 3.1 and 57.5 ± 1.6 %, respectively; while the reassociation value between themselves was 80.4 ± 2.3 %. The results of physiological and biochemical tests allowed the two new isolates to be differentiated phenotypically from the recognized strain U. tangerina JCM 10302T. On the basis of results from this polyphasic study, the strains were characterized as a novel species of the genus Umezawaea, for which the name Umezawaea endophytica sp. nov. is proposed. The type strain is YIM 2047XT (=KCTC 39538T = CPCC 204132T).