Genomic Insight into Shimazuella Soli Sp. Nov. Isolated from Soil and Its Putative Novel Class II Lasso Peptide

The strain designated as AN120528^T was isolated from farmland soil in South Korea. This strain grows well on R2A medium at 28 °C. The cells are an off-white colour and have no hyphae. The phylogenetic analysis indicated that the strain is a member of the genus Shimazuella with a 98.11% similarity to Shimazuella alba KC615^T and a 97.05% similarity to S. kribbensis KCTC 9933^T, respectively. The strain AN120528^T shares common chemotaxonomic features with the other two type strains in the genus. It has MK-9 (H₄) and MK-10 (H₄) as its predominant menaquinones. The major fatty acids are iso-C_14:0, iso-C_15:0, anteiso-C_15:0 and iso-C_16:0. Diphosphatidylglycerol (DPG), phosphatidylethanolamine (PE), phosphatidylglycerol (PG), lipids (L), and aminolipids (AL) were identified as the major cellular polar lipids. Analysis of the peptidoglycan showed the presence of meso-diaminopimelic acid. Whole-genome sequencing revealed that the genome of the strain is approximately 3.3 Mbp in size. The strain showed a 77.5% average nucleotide identity (ANI) with S. alba KC615^T. The genomic DNA (gDNA) G + C content is 39.0%. Based on polyphasic taxonomy analysis, it is proposed that this strain, AN120528^T, represents a novel species in the genus Shimazuella, designated as Shimazuella soli sp. nov. The type stain is AN120528^T (=KCTC 39810^T = DSM 103571^T). Furthermore, shimazuellin I, a new 15-amino-acid peptide, was discovered in the AN120528^T through genome mining; it has the features of a lasso peptide, containing eight amino acids (-G-Q-G-G-S-N-N-D-) that form a macrolactam ring and seven amino acids (-D-G-W-Y-H-S-K-) that form a tail.