Genomic-based classification of Catenulispora pinisilvae sp. nov., novel actinobacteria isolated from a pine forest soil in Poland and emended description of Catenulispora rubra

Abstract

Two actinobacteria, strains NF3 and NH11T, isolated from a pine forest soil, near Torun, Poland were examined for diverse chemotaxonomic and morphological properties that placed them in the genus Catenulispora. They produced an extensively branched stable mycelium, contained LL-diaminopimelic acid as the diamino acid of the peptidoglycan, arabinose as the diagnostic whole-organism sugar, tetra-, hexa- and octa-hydrogenated menaquinones with nine isoprenoid units as the predominant isoprenologues, iso-C16:0 and anteiso-C17:0 as major fatty acids, and formed a well supported clade within the Catenulispora 16S rRNA gene tree together with Catenulispora acidiphila DSM 44928T and Catenulispora rubra DSM 44948T sharing sequence similarities with the latter of 98.8 and 99.0%, respectively. The sizes of whole genome sequences generated for the isolates and the C. rubra strain ranged from 11.20 to 12.80 Mbp with corresponding in silico DNA G+C values of 69.9–70.0%. The isolates and the C. acidiphila and C. rubra strains formed a well supported branch in the actinobacterial phylogenomic tree. Isolates NF3 and NH11T belong to the same species as they have identical 16S rRNA gene sequences, share many chemotaxonomic, cultural and phenotypic features and show very high average nucleotide identity (ANI) and digital DNA:DNA relatedness (dDDH) similarities. They can be distinguished from their closest phylogenomic neighbours by using a combination of chemotaxonomic and phenotypic properties and by ANI and dDDH values well below the thresholds of these metrics used to assign closely related strains to different species. Consequently, we propose that the isolates be classified as a new Catenulispora species, Catenulispora pinisilvae sp. nov., the type strain is NH11T (=DSM 111109T =PCM 3046T). An emended description is given for C. rubra based on data acquired in the present study. Analyses of the draft genomes of the isolates and the C. acidiphila and C. rubra strains revealed the presence of many biosynthetic gene clusters with the potential to synthesize novel drug-like metabolites. In vitro screens showed that the isolates inhibited the growth of Gram-positive bacteria and wheat pathogens belonging to the genus Fusarium.