Streptomyces triticagri sp. nov. and Streptomyces triticirhizae sp. nov., two novel Actinobacteria isolated from the rhizosphere soil of wheat (Triticum aestivum L.)

Two novel Actinobacteria, designated strains NEAU-YY421(T) and NEAU-YY642(T), were isolated from the rhizosphere soil of wheat (Triticum aestivum L.) collected from Zhumadian, Henan Province, PR China and characterized using a polyphasic approach. Phylogenetic analyses based on 16S rRNA gene sequences showed that strains NEAU-YY421(T) and NEAU-YY642(T) belonged to the genus Streptomyces and strain NEAU-YY421(T) was most closely related to Streptomyces fumanus CGMCC 4.1732(T) (97.9 % sequence similarity) and Streptomyces naganishii DSM 40282(T) (97.8 %), and that of strain NEAU-YY642(T) to Streptomyces zhaozhouensis LZS-5(T) (98.0 %) and Streptomyces sedi YIM 65188(T) (97.5 %). The cell walls of the two strains contained LL-diaminopimelic acid as the diagnostic diamino acid and the whole-cell hydrolysates were glucose and ribose. Multilocus sequence analysis using the concatenated sequences of the atpD, gyrB, recA, rpoB and trpB genes showed that the two strains formed separate branches in the genus Streptomyces. Moreover, a combination of DNA-DNA hybridization results and cultural and physiological properties indicated that the two strains can be distinguished from their closest phylogenetic relatives. Therefore, strains NEAU-YY421(T) and NEAU-YY642(T) belong to two novel species in the genus Streptomyces, for which the names Streptomyces triticagri sp. nov. (NEAU-YY421(T)=CGMCC 4.7476(T)=DSM 106775T) and Streptomyces triticirhizae sp. nov. (NEAU-YY642(T)=CCTCC AA 2018092(T)=DSM 107172(T)) are proposed, respectively.