Abstract

Two Gram-positive, rod-shaped, motile, endospore-forming strains, FIAT-49780(T) and FIAT-49732(T) were isolated from a citrus rhizosphere soil sample. The optimal growth temperatures for strains FIAT-49780(T) and FIAT-49732(T) were 45 and 35-40 degrees C, respectively. The optimal growth pH for strains FIAT-49732(T) and FIAT-49780(T) were pH 8.0 and pH 6.0, respectively. The 16S rRNA gene sequence similarity between FIAT-49780(T) and FIAT-49732(T) was 98.6%. Strains FIAT-49780(T) and FIAT-49732(T) shared 97.9-98.4% 16S rRNA gene sequence similarities to the type strain of Lederbergia wuyishanensis. In phylogenetic trees (based on 16S rRNA gene sequence), strains FIAT-49732(T) and FIAT-49780(T) Glade with Lederbergia members. Both strains contained meso-diaminopimelic acid in their cell-wall peptidoglycan and MK-7 was the only isoprenoid quinone detected. The major fatty acids of strains FIAT-49732(T) and FIAT-49780(T) were anteiso-C-15:0 and iso-C-15:0. The polar lipids of strain FIAT-49780(T) were diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylglycerol, an unidentified aminophospholipid, unidentified phospholipid and unidentified lipids while strain FIAT-49732(T) contained diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylglycerol, an unidentified glycolipid, unidentified aminolipid and unidentified phospholipid. The genomic DNA G+C content of strains FIAT-49780(T) and FIAT-49732(T) were 37.0 and 36.7%, respectively. The digital DNA-DNA hybridization and average nucleotide identity values between strains FIAT-49780(T) and FIAT-49732(T) and with other members of the genus Lederbergia were below the cut-off level for species delineation. Thus, based on the above results, strains FIAT-49780(T) and FIAT-49732(T) represent two novel species of the genus Lederbergia, for which the names Lederbergia citri sp. nov., and Lederbergia citrisecundus sp. nov., are proposed. The type strains are FIAT-49780(T) (=CCTCC AB 2019242(T)=LMG 31583(T)) and FIAT-49732(T) (=CCTCC AB 2019246(T)=LMG 31584(T)).