Open AccessDiverse, yet‐to‐be‐cultured members of the Rubrobacter subdivision of the Actinobacteria are widespread in Australian arid soils
Author(s) -
Holmes Andrew J,
Bowyer Jocelyn,
Holley Marita P,
O'Donoghue Madeline,
Montgomery Meg,
Gillings Michael R
Publication year - 2000
Publication title -
fems microbiology ecology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.377
H-Index - 155
eISSN - 1574-6941
pISSN - 0168-6496
DOI - 10.1111/j.1574-6941.2000.tb00733.x
Subject(s) - biology , phylogenetic tree , actinobacteria , arid , ribosomal dna , ribosomal rna , ecology , genetics , 16s ribosomal rna , gene
Phylogenetic analyses of ribosomal RNA gene sequences (rDNAs) retrieved from an Australian desert soil sample (Sturt National Park) revealed the presence of a number of clones which branched deeply from the high GC Gram‐positive division line of descent. The most abundant group of these clones were related to Rubrobacter . An oligonucleotide probe was designed to have broad specificity to Rubrobacter and relatives. This probe was used to interrogate eight rDNA libraries representing four distinct land forms within the Australian arid zone. Relative abundance of Rubrobacter ‐relatives in these samples ranged from 2.6 to 10.2%. Clones from these libraries were selected for sequence analysis on the basis of a heteroduplex mobility assay to maximise the diversity represented in the sample. Phylogenetic analyses of these rDNA clones and Rubrobacter ‐related clones reported in the literature show strong support for three distinct groups. Database‐searching revealed ‘Rubrobacteria’ were relatively abundant in a number of published soil rDNA libraries but absent from others. A PCR assay for group‐1 ‘Rubrobacteria’ was used to test for their presence in 21 environmental samples. Only marine and arid‐zone soil samples gave positive PCR results. Taken together these results indicate ‘Rubrobacteria’ are a widespread group of variable abundance and diversity.