Paenibacillus wuxiensis sp. nov., a Novel Bacterium Capable of Producing Indole-3-Acetic Acid (IAA) and Inhibiting Rhizoctonia solani Kühn Isolated from Agricultural Soil.

A Gram-stain-positive bacterium, which produced indole-3-acetic acid (IAA) and inhibited Rhizoctornia solani Kühn, designated strain P4, was isolated from agricultural soil in Wuxi city, Jiangsu province, PR China. Cells were rod-shaped, facultatively anaerobic, endospore-forming, motile by peritrichous flagella. Growth occurred at 15-42 °C (optimum at 30 °C), pH 5.0-9.0 (optimum pH 7.0-7.5) and with 0-3.0% NaCl (w/v; optimum, 0.5%). The 16S rRNA gene sequence analysis showed that strain P4 is a member of the genus Paenibacillus, closely related to Paenibacillus alvei DSM 29 (98.3%), followed by P. marinisediminis S27 (96.0%), P. aquistagni 11 (95.9%) and P. profundus SI 79 (95.5%). Phylogenetic trees based on 16S rRNA gene and genomic sequences indicated that strain P4 was clustered in the genus Paenibacillus and formed a subclade with P. alvei DSM 29. The genome size of P4 was 6.7 Mb with a G + C content of 46.6%. The average nucleotide identity (ANI) and digital DNA-DNA hybridization (dDDH) values between the genomes of strain P4 and seven closely related type strains ranged from 71.5-84.8% to 20.6-28.7%, respectively. The percentage of conserved proteins (POCP) values between strain P4 and its related strains ranged from 57.2 to 73.5%. The major fatty acids (≥ 5%) were anteiso-C, iso-C, C, iso-C and anteiso-C. The polar lipids profile consisted of phosphatidylethanolamine (PE), phosphatidylmonomethylethanolamine (PME), phosphatidylglycerol (PG), unidentified aminolipid (AL), three unidentified glycolipids (GL1-3), three unidentified phospholipids (PL1-3), five unidentified aminophospholipids (APL1-5) and five unidentified lipids (L1-5). The only isoprenoid quinone was menaquinone-7 (MK-7) and the cell wall peptidoglycan was meso-DAP. Based on phylogenetic, genomic and phenotypic data, strain P4 was considered to represent a novel species in genus Paenibacillus, for which the name Paenibacillus wuxiensis was proposed, with P4 (= MCCC 1K09189 = KCTC 43706) as the type strain.