Genomewide Identification of Regulatory Elements for the Virulence Factors of Burkholderia glumae strain 336gr-1

Burkholderia glumae causes bacterial panicle blight of rice and the phytotoxin, toxoflavin, and lipase are the major pathogenicity factors of this pathogen. To support molecular genetics and functional genomics studies for the bacterial pathogenesis by B. glumae, the entire genome of our virulent reference strain, 336gr-1, was sequenced using Illumina platform. Sequence alignment and annotation was based on reference sequence of another B. glumae strain, BGR1. In an attempt to identify the regulatory elements controlling the production of toxoflavin and lipase, random mutagenesis of the B. glumae 336gr-1 genome was carried out using a mini-Tn5 derivative, mini-Tn5gus, and the mutants showing altered production of toxoflavin and lipase were screened. Among more than 20,000 mutants randomly mutated with mini-Tn5gus, 56 mutants were screened based on their altered phenotypes in toxin and lipase production. With the complete sequence information of the B. glumae 336gr-1 genome, mutated genes encoding putative positive or negative regulators of the virulence factors could be easily identified by sequencing the flanking regions of mini-Tn5gus in the screened mutants.