Paenibacillus artemisiicola sp. nov. and Paenibacillus lignilyticus sp. nov., two new endophytic bacterial species isolated from plant roots

Abstract

Two Gram-positive, endospore-forming, rod-shaped bacterial strains designated MWE-103T and DLE-14T were isolated from plant roots. The 16S rRNA gene sequence analysis indicated that strain MWE-103T was closely related to Paenibaillus sacheonensis SY01T with a sequence similarity of 97.82 %, and strain DLE-14T to Paenibacillus rhizoryzae IZS3-5T with 99.09 % similarity. The orthologous average nucleotide identity and digital DNA–DNA hybridization values using whole genome data indicated that strains MWE-103T and DLE-14T could be readily distinguished from the mostly related species. Both strains grew at mesophilic temperature ranges, and grew best at pH 6 and in the absence of NaCl. The major fatty acid in both strains was anteiso-C15 : 0, but their relative proportions differed. The predominant quinone of both strains was menaquinone 7, the cell-wall diamino acid was meso-diaminopimelic acid, and the diagnostic polar lipids were diphosphatidylglycerol, phosphatidylethanolamine and phosphatidylglycerol, which were consistent with those of related species. Amylase and cellulase activities were positive for both strains. Strain DLE-14T exhibited the potential for lignin degradation. The DNA G+C contents of strain MWE-103T and DLE-14T were 60.9 and 50.8 mol% respectively. The genomes of the two strains revealed potential plant-growth-promoting characteristics such as nitrogen fixation, siderophore production and phosphate solubilization. Based on phylogenetic and phenotypic evidence, strains MWE-103T and DLE-14T should each be recognized as a novel species of Paenibacillus , for which the names Paenibacillus artemisiicola sp. nov. (type strain: MWE-103T=KCTC 43287T=JCM 34503T) and Paenibacillus lignilyticus sp. nov. (type strain: DLE-14T=KCTC 43288T=JCM 34504T) are proposed.