Affiliation:
1. Department of Microbiology, Faculty of Science, Kasetsart University, Chatuchak, Bangkok 10900, Thailand
2. Biodiversity Center Kasetsart University (BDCKU), Bangkok 10900, Thailand
Abstract
The taxonomic position of a novel actinomycete, designated strain RS10V-4T, was determined using a polyphasic approach. Strain RS10V-4T was isolated from paddy rhizosphere soil of rice plant (Oryzae sativa L.). The morphological, physiological and chemotaxonomic properties were consistent with its classification in the genus
Streptomyces
. On the basis of 16S rRNA gene sequence analysis, strain RS10V-4T belongs to the genus
Streptomyces
and had the highest sequence similarity to
Streptomyces noursei
NBRC 15452T (98.3 %). The G+C content of the genomic DNA was 73.8 %. Digital DNA–DNA hybridization and average nucleotide identity values between the genome sequences of strain RS10V-4T and S.noursei ATCC 11455T were lower than the recommendation threshold values for the recognition of species within the same genus. The whole-cell hydrolysates of strain RS10V-4 T contained
ll
-diaminopimelic acid as the diagnostic diamino acid and the whole-cell sugars were glucose and ribose. The predominant menaquinones were MK-9(H6) and MK-9(H8). The predominant cellular fatty acids (>10 %) were iso-C16 : 0, anteiso-C15 : 0, iso-C14 : 0 and iso-C15 : 0. The polar lipids of strain RS10V-4T contained diphosphatidylglycerol, hydroxyphosphatidylethanolamine, phosphatidylethanolamine, phosphatidylinositol, an unidentified aminolipid, two unidentified lipids and an unidentified phospholipid. On the basis of these phenotypic and genotypic characteristics, it is supported that strain RS10V-4T represents a novel species of the genus
Streptomyces
, for which the name Streptomyces rhizoryzae sp. nov. is proposed. The type strain is RS10V-4T (=TBRC 15167T=NBRC 115345T). In addition, the comparison of the whole genome sequences and phenotypic features suggested that
S. noursei
and
S. albulus
belong to the same species. Therefore, it is proposed that
S. albulus
is reclassified as a later heterotypic synonym of
S. noursei
.
Subject
General Medicine,Ecology, Evolution, Behavior and Systematics,Microbiology