Two Gram-stain-positive, aerobic, endospore-forming bacterial strains, isolated from the rhizosphere of Zea mays were studied for their detailed taxonomic allocation. Based on 16S rRNA gene sequence similarity comparisons, both strains JJ-7T and JJ-60T were shown to be members of the genus Paenibacillus. Strain JJ-7T was most closely related to the type strains of Paenibacillus tianjinensis (99.6 %) and P. typhae (98.7 %), and strain JJ-60T to Paenibacillus etheri (99.5 %). The 16S rRNA gene sequence similarities to all other Paenibacillus species were ≤98.4 %. Both strains JJ-7T and JJ-60T showed 97.6 % 16S rRNA gene sequence similarity between each other. Genomic comparisons showed that the average nucleotide identity and digital DNA-DNA hybridization values to next related type strain genomes were always <94 and <56 %, respectively. The polar lipid profiles of both strains contain a number of phospholipids including diphosphatidylglycerol, phosphatidylglycerol and phosphatidylethanolamine, which is in accord with the genus Paenibacillus. The major quinone was MK-7 in both strains. Major fatty acids were iso- and anteiso-branched. Physiological and biochemical characteristics allowed a further phenotypic differentiation of strains JJ-7T and JJ-60T from the most closely related species. Thus, each strain represents a novel species of the genus Paenibacillus, for which the names Paenibacillus auburnensis sp. nov. and Paenibacillus pseudetheri sp. nov. are proposed, with JJ-7T (=CIP 111892T=DSM 111785T=LMG 32088T=CCM 9087T) and JJ-60T (=CIP 111894T=DSM 111787T=LMG 32090T=CCM 9086T) as the type strains, respectively.
Keywords: Paenibacillus auburnensis; Paenibacillus pseudetheri; Zea mays; endophyte; plant associated; taxonomy.