Description of Streptomyces fabae sp. nov., a producer of antibiotics against microbial pathogens, isolated from soybean (Glycine max) rhizosphere soil.

An actinomycete, designated strain T66T and isolated from soybean rhizosphere soil at Gyeonggi Siheung Sorae in the Republic of Korea, has antibiotic activity against a broad range of microbial pathogens. The strain was determined to be closely related to several known species in the genus Streptomyces on the basis of 16S rRNA gene sequence data (97.73-98.07 % similarity). The strain exhibited cell-wall chemotype I and phospholipid type II. The menaquinones present were MK-9 (H6), MK-9 (H8) and MK-10 (H2). Major fatty acids were anteiso-C15 : 0, iso-C16 : 0, iso-C15 : 0, and anteiso-C17 : 0. The level of DNA-DNA relatedness between strain T66T and closely related type strains was determined to be below 40 %. Strain T66T had spiral spore chains and a rugose spore surface that is different from its closest relatives. Comparison of the genotypic and phenotypic features confirmed that strain T66T ( = KEMB 9005-219T = KACC 18226T = NBRC 110902T) should be considered as the type strain of a novel species in the genus Streptomyces, for which the name Streptomyces fabae sp. nov. is proposed.