Pseudonocardia nigra sp. nov., isolated from Atacama Desert rock.

Eleven actinobacterial strains were isolated from a rock sample collected in the Atacama Desert. Molecular typing by BOX-PCR divided the strains into three clusters and showed that, although very similar, they were not clones. Three strains, ATK01, ATK03T and ATK17, each representing one of the defined BOX clusters, were chosen for further characterization. Phylogenetic analysis indicated that the strains were related to the genus Pseudonocardia and were recovered in a cluster together with Pseudonocardia bannensis YIM 63101T and Pseudonocardia xinjiangensis AS 4.1538T. Chemotaxonomic analyses confirmed their affiliation to the genus Pseudonocardia but differences were found between the new strains and their closest phylogenetic relatives. Physiological and fatty acid analyses also revealed differences between these strains and their phylogenetic neighbours supporting their status as a distinct species. Based on the overall data, it is proposed that strains ATK01, ATK03T and ATK17 represent a novel species of the genus Pseudonocardia for which the name Pseudonocardia nigra sp. nov. is proposed (type strain ATK03T=DSM 104088T=CECT 9183T).