Abstract
ES5-4(T), a Gram-positive, motile, aerobic, and rod-shaped strain, was isolated from the rhizosphere of Galinsoga parviflora growing in the selenium-rich ore area of Enshi, Hubei Province, China. This strain can grow at pH levels of 5.0-10.0 and temperatures of 4-42 °C, with optimal growth at pH 7.0 and 28 °C. It was found to resist NaCl up to 5% (w/v), with an optimal growth condition of 0.5-1.0%. The strain exhibited tolerance to selenite (Se(4+)) concentrations up to 5000 mg/L. The major fatty acids of the ES5-4(T) strain were anteiso-C(15:0) (46.5%) and C(16:0) (21.7%), its predominant respiratory quinone was MK-7, and its polar lipids included diphosphatidylglycerol (DPG), phosphatidylethanolamine (PE), phosphatidylglycerol (PG), and an unidentified phospholipid (PL). The presence of the 16S rRNA gene sequence implies that ES5-4(T) belongs to a member of the genus Paenibacillus, with the highest sequence similarity of 98.4% to Paenibacillus pabuli NBRC 13638(T). The bac120 tree also confirmed that the strain is within the genus Paenibacillus. The average nucleotide identity (ANI) and digital DNA-DNA hybridization (dDDH) values between ES5-4(T) and closely related members of the genus Paenibacillus were all below the cutoff levels of 95-96% and 70%, respectively. Based on a polyphasic approach, including phenotypic, chemotaxonomic, and phylogenetic analyses, the ES5-4(T) strain is proposed as a novel species of the genus Paenibacillus, for which the name Paenibacillus hubeiensis sp. nov. is proposed. This type strain is designated as ES5-4(T) (=GDMCC 1.3540(T) = KCTC 43478(T)).