Glycomyces luteolus sp. nov., a novel actinomycete isolated from rhizosphere soil of wheat (Triticum aestivum L.)

Abstract

Three Gram-stain positive, aerobic actinomycete strains, designated NEAU-A15T, NEAU-A13 and NEAU-C4, were isolated from rhizosphere soil of wheat (Triticum aestivum L.) collected from Langfang, Hebei Province, China. Based on their morphological characteristics, biochemical features and molecular phylogenetic studies, these strains were concluded to belong to a new member of the genus Glycomyces. 16S rRNA gene sequence analysis showed that strain NEAU-A15T shares 99.91% and 99.80% 16S rRNA gene sequence similarity with NEAU-A13 and NEAU-C4, respectively, and these three strains showed high sequence similarities to Glycomyces algeriensis DSM 44727T (99.24, 99.45, 99.38%), Glycomyces lechevalierae DSM 44724T (98.97, 99.17, 99.11%) and Glycomyces rutgersensis DSM 43812T (98.83, 99.04, 98.97%). Phylogenetic analysis indicated that these three strains clustered together and formed a cluster with Glycomyces tritici NEAU-C2T (97.30, 97.73, 99.48%), G. algeriensis DSM 44727T, G. lechevalierae DSM 44724T and G. rutgersensis DSM 43812T. These three strains were observed to contain MK-10(H2), MK-10(H6) and MK-11 as menaquinones. The whole cell sugar profiles were found to contain galactose, ribose and xylose. The polar lipids were found to consist of diphosphatidylglycerol, phosphatidylinositol, phosphatidylglycerol, phosphoglycolipid, phosphatidylinositol mannoside and an unidentified glycolipid. The major fatty acids were identified as anteiso-C15:0, iso-C16:0, anteiso-C17:0 and iso-C15:0. The DNA-DNA hybridization values between strain NEAU-A15T and NEAU-A13/NEAU-C4 were 86.2 ± 2.3% and 83.4 ± 3.5%, respectively. The values between these three strains and their close phylogenetic relatives were 48-52%, supporting the conclusion that they belong to a distinct genomic species. An array of phenotypic characteristics also differentiated these isolates from their closely related species. On the basis of the genetic and phenotypic properties, strains NEAU-A15T, NEAU-A13 and NEAU-C4 can be classified as representatives of a novel species of the genus Glycomyces, for which the name Glycomyces luteolus sp. nov., is proposed. The type strain is NEAU-A15T (= DSM 104643T = CGMCC 4.7394T).