Characterization of a Novel Lentzea Species Isolated from the Kumtagh Desert and Genomic Insights into the Secondary Metabolite Potential of the Genus

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  • A novel actinobacterial strain, designated E54T, was isolated from a hyper-arid desert soil sample collected from the Kumtagh Desert in Dunhuang, Gansu Province, China. Phylogenetic analysis based on 16S rRNA gene sequences placed strain E54T within the genus Lentzea, showing highest similarity to Lentzea waywayandensis DSM 44232T (98.9%) and Lentzea flava NBRC 15743T (98.5%). However, whole-genome comparisons revealed that the average nucleotide identity (ANI) and digital DNA-DNA hybridization (dDDH) values between E54T and these related strains were below the thresholds for species delineation. Strain E54T exhibited typical morphological characteristics of the genus Lentzea, forming a branched substrate. It grew optimally at 28-30 degrees C, pH 7.0-9.0, and tolerated up to 10% NaCl. The cell wall contained meso-diaminopimelic acid, the predominant menaquinone was MK-9(H4), and major fatty acids included iso-C16:0. The polar lipid profile comprised diphosphatidyl glycerol, phosphatidyl ethanolamine, phosphatidyl inositol, hydroxyphosphatidyl ethanolamine, and an unidentified lipid. The characteristic amino acid type of the cell wall was meso-DAP. Whole-cell hydrolysis experiments revealed the characteristic cell wall sugar fractions: ribose and galactose. The genome of strain E54T is approximately 8.0 Mb with a DNA G+C content of 69.38 mol%. Genome mining revealed 39 biosynthetic gene clusters (BGCs), including non-ribosomal peptide synthetases (NRPS), polyketide synthases (PKS), terpenes, and siderophores. Comparative antiSMASH-based genome analysis across 38 Lentzea strains further demonstrated the genus' remarkable biosynthetic diversity. NRPS and type I PKS (T1PKS) were the most prevalent BGC types, indicating a capacity to synthesize structurally complex and pharmacologically relevant metabolites. Together, these findings underscore the untapped biosynthetic potential of the genus Lentzea and support the proposal of strain E54T as a novel species. The strain E54T (=JCM 34936T = GDMCC 4.216T) should represent a novel species, for which the name Lentzea xerophila sp. nov. is proposed.