Streptosporangium jomthongense sp. nov., an actinomycete isolated from rhizospheric soil and emendation of the genus Streptosporangium

Abstract

A novel actinomycete, strain 30EHS(T), was isolated from the rhizospheric soil under an elephant ear plant (Caladium bicolor) in Jomthong district, Bangkok, Thailand. Phylogenetic analysis based on 16S rRNA gene sequences revealed that strain 30EHS(T) fell within the cluster of the genus Streptosporangium. Chemical composition analysis confirmed that the strain represented a member of the genus Streptosporangium even though this strain produced a tightly packed single spore on aerial hyphae. Phylogenetic analysis based on 16S rRNA gene sequences demonstrated that strain 30EHS(T) was most closely related to Streptosporangium fragile NBRC 14311(T) (98.1%), Streptosporangium carneum NBRC 15562(T) (97.8%) and Streptosporangium violaceochromogenes NBRC 15560(T) (97.4%). The DNA-DNA hybridization relatedness values between strain 30EHS(T) and the above three strains were below 70%. Based on combined data for phylogenetic analysis, DNA-DNA hybridization relatedness and physiological characteristics, it was concluded that strain 30EHS(T) should be classified as representing a novel species of the genus Streptosporangium. We propose the name Streptosporangium jomthongense sp. nov., with the type strain 30EHS(T) ( = BCC 53154(T) = NBRC 110047(T)). An emended description of the genus Streptosporangium is also proposed.