Study on Diversity of Acidophilic Rare Actinomycetes from Acidic Soil

acidophilic actinomycetes were isolated from 10 acidic soil samples collected in Jiangxi Province, Yunnan Province and Beijing. About 90% of them were streptomycetes. 20 representatives of rare actinomycetes were selected by a combination of morphological feature, pH range for growth and cell wall amino acid component. They gave 11 different ARDRA patterns when digested with enzymes BstUⅠ and HhaⅠ. 9 strains shared the same ARDRA pattern, which was moderately similar to the patterns of another 4 strains and distinct from those of the remaining 7 strains. On the basis of 16S rDNA sequence analysis, 18 of the 20 selected strains were assigned to 6 recognized genera. 13 of them fall within the genus Nocardia, and the other 5 strains belong to genera Agrococcus, Arthrobacter, Kitasatospora, Kocuria and Streptacidiphilus, respectively. 2 of the selected strains are members of an as-yet-unnamed novel family (Ellin5034 group). The results show the good diversity of acidophilic rare actinomycetes in acidic soil, with Nocardiae predominant.