Sutcliffiella rhizosphaerae sp. nov. isolated from roots.

Abstract

An aerobic, Gram-staining-positive, endospore-forming bacterium, isolated from the rhizosphere of roots of maize (Zea mays), was taxonomically studied. On the basis of 16S rRNA gene sequence similarity comparisons, strain JJ-125T clustered together with species of the genus Sutcliffiella and showed the highest similarities with Sutcliffiella zhanjiangensis (98.7 %). The 16S rRNA gene sequence similarities to the sequences of the type strains of other species of the genus Sutcliffiella were <98.4 %. The genome sequence of JJ-125T was 4 516 360 bp long and had a DNA G+C content of 37.3 %. A DNA-DNA hybridization with the type strain of S. zhanjiangensis DSM 23010T resulted in values of 42.3 and 43.9 % (reciprocal). The average nucleotide identity, average amino acid identity and digital DNA-DNA hybridization values between the JJ-125T genome assembly and those of the other type strains of species of the genus Sutcliffiella were <75%, <80 % and <21 %, respectively. Chemotaxonomic features supported the grouping of the strain with the genus Sutcliffiella, e.g. the major fatty acids included iso-C15 : 0, iso-C17 : 1 ω10c and iso-C17 : 0, the polar lipid profile contained the major components diphosphatidylglycerol, phosphatidylglycerol and phosphatidylethanolamine, the only quinone was menaquinone MK-7 and the characteristic diamino acid was meso-diaminopimelic acid. Physiological and biochemical test results were also different from those of the most closely related species. As a consequence, JJ-125T represents a novel species of the genus Sutcliffiella, for which we propose the name Sutcliffiella rhizosphaerae sp. nov., with JJ-125T (= CIP 111883T = LMG 32156T = CCM 9046T) as the type strain.