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

Two Gram-positive, endospore-forming, rod-shaped bacterial strains designated MWE-103(T) and DLE-14(T) were isolated from plant roots. The 16S rRNA gene sequence analysis indicated that strain MWE-103(T) was closely related to Paenibaillus sacheonensis SY01(T) with a sequence similarity of 97.82%, and strain DLE-14(T) to Paenibacillus rhizoryzae IZS3-5(T) with 99.09% similarity. The orthologous average nucleotide identity and digital DNA-DNA hybridization values using whole genome data indicated that strains MWE-103(T )and DLE-14(T) 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-C-15:0, 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-14(T) exhibited the potential for lignin degradation. The DNA G+C contents of strain MWE-103(T) and DLE-14(T) 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-103(T) and DLE-14(T) should each be recognized as a novel species of Paenibacillus, for which the names Paenibacillus artemisiicola sp. nov. (type strain: MWE-103(T)=KCTC 4328(T)=JCM 34503(T)) and Paenibacillus lignilyticus sp. nov. (type strain: DLE-14(T)=KCTC 43288(T)=JCM 34504(T)) are proposed.