Microbispora sitophila sp. nov., a novel actinobacterium isolated from rhizosphere soil of wheat (Triticum aestivum L.).

Abstract

A novel actinobacterium, designated strain NEAU-D428T, was isolated from rhizosphere soil of wheat and characterized using a polyphasic approach. Morphological and chemotaxonomic characteristics of the strain coincided with members of the genus Microbispora. The 16S rRNA gene sequence analysis showed that the isolate was most closely related to Microbispora bryophytorum NEAU-TX2-2T (99.2 %). Phylogenetic analysis based on the 16S rRNA gene sequences indicated that the strain clustered with Microbispora clausenae CLES2T (99.1 %), but formed a separate subclade in the phylogenomic tree within the genus Microbispora. The menaquinones were identified as MK-9(H4), MK-9(H2) and MK-9(H0). The phospholipid profile was found to consist of diphosphatidylglycerol, phosphatidylmonomethylethanolamine, phosphatidylethanolamine, ninhydrin-positive glycophospholipid, phosphatidylinositol and phosphatidylinositol mannoside. The major fatty acids were identified as iso-C16 : 0, C16 : 0, 10-methyl C17 : 0 and C18 : 0. Digital DNA-DNA hybridization and average nucleotide identity values between strain NEAU-D428T and M. bryophytorum NEAU-TX2-2T, Microbispora camponoti 2C-HV3T, M. clausenae CLES2T, 'Microbispora cellulosiformans' Gxj-6T and Microbispora fusca NEAU-HEGS1-5T were 47.6 and 92.2 %, 47.5 and 92.2 %, 55.9 and 94.0 %, 33.1 and 86.8 %, and 33.6 and 87.1 %, respectively. These results and some physiological and biochemical properties demonstrated that the strain could be distinguished from its closest relatives. Therefore, it is proposed that strain NEAU-D428T should be classified as representative of a novel species of the genus Microbispora, for which the name Microbispora sitophila sp. nov. is proposed. The type strain is NEAU-D428T (=CGMCC 4.7523T=DSM 109822T).