A Comparative Study of Malaysian and Japanese Actinomycetes Using a Simple Identification Method Based on Partial 16S rDNA Sequence

Abstract

A comparative analysis was performed on the taxonomy of actinomycete isolates of Malaysia and Japan. The taxonomical positions of isolates were determined using a simple identification method based on 16S rDNA partial sequence homology. The 16S rDNA partial sequence determination was made by direct PCR and direct sequencing. Simple identification was attempted for each of the 1128 actinomycete isolates for each country. We succeeded in simple identification of 790 Malaysian and 981 Japanese isolates. Malaysian isolates belonged to 9 families, 23 genera, and 185 species, including one genus as yet undescribed. The Japanese isolates belonged to 9 families, 22 genera, and 207 species. There was little taxonomical overlap between Malaysian isolates and Japanese isolates. Only 14% of the species and only 50% of the genera occurred in both groups. These results indicate that a group of actinomycetes of greater taxonomic diversity can be obtained when gathered from both regions, rather than from one or the other. Among Malaysian isolates, two strains were found that apparently do not belong to any known genus. Phylogenetic analysis indicates that they belong to the suborder Sreptosporangineae. The existence of candidate strains of a novel genus suggests that Malaysian actinomycetes have not been thoroughly investigated and therefore has promising potential as a source for novel bioactive compounds.