A single mini-Tn5km1 insertion in the genome of Paraburkholderia oxyphila OX-01, a proteobacterium that utilizes (+)-catechin as a carbon source, induced mutants defective in the (+)-catechin catabolism

Abstract

Little information is available on how (+)-catechin is decomposed by soil bacteria. Paraburkholderia oxyphila OX-01 was previously isolated as a (+)-catechin catabolizing agent. This study succeeded in isolating many P. oxyphila OX-01 mutants defective in catabolizing (+)-catechin by a single insertion of the transposon miniTn5km1 in the genome. Aromatics utilization, (+)-catechin decomposing profiles, and mini-Tn5km1 insertion sites were variable among mutants. Nucleotide sequencing of insertion sites in representative mutants revealed that mutants that could not utilize all aromatics tested but decompose (+)-catechin to some extent had the insertion in tricarboxylic acid cycle-related genes, whereas those that only could not utilize (+)-catechin and (+)-taxifolin so far had the insertion in transporter-related genes. The P. oxyphila OX-01 gene library constructed in the pLAFER5 cosmid restored the wild-type phenotype in mutants. Mini-Tn5km1 insertion mutagenesis is useful in isolating various P. oxyphila mutants that can be subjected to complementation analysis with the pLAFR5-based gene library.