Micromonospora oryzae sp. nov., isolated from roots of upland rice

Abstract

An actinomycete strain, designated CP2R9-1^T, was isolated from root internal tissues of upland rice (<i>Oryza sativa</i>). Based on a polyphasic approach, strain CP2R9-1^T was characterized as a member of the genus <i>Micromonospora. meso-</i>Diaminopimelic acid and 3-OH-diaminopimelic acid were present in the cell-wall peptidoglycan. The polar lipids were diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylglycerol, phosphatidylinositol, phosphatidylinositol mannosides, two unidentified phospholipids and four unidentified polar lipids. Predominant menaquinones were MK-9(H₄), MK-9(H₆) and MK-10(H₄). Whole-cell sugars consisted of ribose, xylose, arabinose and glucose. Phylogenetic analysis of the nearly complete 16S rRNA gene sequence suggested that strain CP2R9-1^T was closely related to <i>Micromonospora haikouensis</i> 232617^T (99.32 % similarity), <i>Micromonospora carbonacea</i> DSM 43168^T (99.18 %) and <i>Micromonospora krabiensis</i> MA-2^T (99.16 %). Strain CP2R9-1^T was distinct from its closest relatives based on low levels of DNA-DNA relatedness (21.3 ± 0.1-41.7 ± 0.7 %) and phenotypic differences. The results presented in this study showed that strain CP2R9-1^T represents a novel species of the genus <i>Micromonospora</i>, for which the name <i>Micromonospora oryzae</i> sp. nov. is proposed. The type strain is CP2R9-1^T ( = BCC 67266^T = NBRC 110007^T).