
Molecular Evolution of Aromatic Polyketides and Comparative Sequence Analysis of Polyketide Ketosynthase and 16S Ribosomal DNA Genes from Various Streptomyces Species
Author(s) -
Mikko MetsäKetelä,
Laura M. Halo,
Eveliina Munukka,
Juha Hakala,
Pekka Mäntsälä,
Kristiina Ylihonko
Publication year - 2002
Publication title -
applied and environmental microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.552
H-Index - 324
eISSN - 1070-6291
pISSN - 0099-2240
DOI - 10.1128/aem.68.9.4472-4479.2002
Subject(s) - polyketide , biology , phylogenetic tree , 16s ribosomal rna , gene , polyketide synthase , dna sequencing , genetics , ribosomal rna , dna , biosynthesis
A 613-bp fragment of an essential ketosynthase gene from the biosynthetic pathway of aromatic polyketide antibiotics was sequenced from 99 actinomycetes isolated from soil. Phylogenetic analysis showed that the isolates clustered into clades that correspond to the various classes of aromatic polyketides. Additionally, sequencing of a 120-bp fragment from the gamma-variable region of 16S ribosomal DNA (rDNA) and subsequent comparative sequence analysis revealed incongruity between the ketosynthase and 16S rDNA phylogenetic trees, which strongly suggests that there has been horizontal transfer of aromatic polyketide biosynthesis genes. The results show that the ketosynthase tree could be used for DNA fingerprinting of secondary metabolites and for screening interesting aromatic polyketide biosynthesis genes. Furthermore, the movement of the ketosynthase genes suggests that traditional marker molecules like 16S rDNA give misleading information about the biosynthesis potential of aromatic polyketides, and thus only molecules that are directly involved in the biosynthesis of secondary metabolites can be used to gain information about the biodiversity of antibiotic production in different actinomycetes.