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-YY421T and NEAU-YY642T, 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-YY421T and NEAU-YY642T belonged to the genus Streptomyces and strain NEAU-YY421T was most closely related to Streptomyces fumanus CGMCC 4.1732T (97.9 % sequence similarity) and Streptomyces naganishii DSM 40282T (97.8 %), and that of strain NEAU-YY642T to Streptomyces zhaozhouensis LZS-5T (98.0 %) and Streptomyces sedi YIM 65188T (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 atp D, gyr B, rec A, rpo B and trp B 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-YY421T and NEAU-YY642T belong to two novel species in the genus Streptomyces, for which the names Streptomyces triticagri sp. nov. (NEAU-YY421T=CGMCC 4.7476T=DSM 106775T) and Streptomyces triticirhizae sp. nov. (NEAU-YY642T=CCTCC AA 2018092T=DSM 107172T) are proposed, respectively.