Development of a Kribbella-specific isolation medium and description of Kribbella capetownensis sp. nov. and Kribbella speibonae sp. nov., isolated from soil.

Two actinobacterial strains were isolated from samples collected from the University of Cape Town, South Africa. A third actinobacterial strain was isolated from soil collected in the town of Stellenbosch, South Africa, using a newly-developed Kribbella-selective medium. Analysis of the 16S rRNA genes showed that the three strains belonged to the genus Kribbella. A multilocus sequence analysis using the concatenated gene sequences of the gyrB, rpoB, relA, recA and atpD genes showed that strains YM55T and SK5 were most closely related to the type strains of Kribbella sindirgiensis and Kribbella soli, while strain YM53T was most closely related to the type strain of Kribbella pittospori. Digital DNA-DNA hybridisation and Average Nucleotide Identity (ANI) analyses showed that strains YM55T and SK5 belong to the same genomic species (OrthoANI value = 98.4%), but are distinct from the genomic species represented by the type strains of K. sindirgiensis (OrthoANI values < 95.6%) and K. soli (OrthoANI values < 91.4%). Strain YM53T is distinct from the genomic species represented by the type strain of K. pittospori (OrthoANI value = 94.0%). Phenotypic comparisons showed that strains YM55T and SK5 are distinct from the type strains of K. sindirgiensis and K. soli and that strain YM53T is distinct from the type strain of K. pittospori. Strains YM53T and YM55T are thus presented as the type strains of novel species, for which the names Kribbella capetownensis sp. nov. (= DSM 29426T = NRRL B-65062T) and Kribbella speibonae sp. nov. (= DSM 29425T = NRRL B-59161T), respectively, are proposed.

Kribbella podocarpi sp. nov., isolated from the leaves of a yellowwood tree (Podocarpus latifolius).

An endophytic actinobacterial strain was isolated from a yellowwood tree growing on the slope of Devil's Peak, Cape Town, South Africa. Analysis of the 16S rRNA gene showed that the strain belongs to the genus Kribbella. Phylogenetic analyses using the 16S rRNA gene and multilocus sequence analysis using the concatenated gene sequences of the gyrB, rpoB, relA, recA and atpD genes showed that strain YPL1T is closely related to the type strains of Kribbella karoonensis and Kribbella shirazensis. DDH experiments showed that strain YPL1T is a distinct genomic species from its close phylogenetic relative, K. karoonensis Q41T. Physiological comparisons further showed that strain YPL1T is phenotypically distinct from the type strains of Kribbella jejuensis, Kribbella aluminosa, K. karoonensis, K. shirazensis and Kribbella swartbergensis. Strain YPL1T is thus presented as the type strain of a novel species, for which the name Kribbella podocarpi sp. nov. (= DSM 29424T = NRRL B-65063T), is proposed.