Burkholderia thailandensis Methylated Hydroxyalkylquinolines: Biosynthesis and Antimicrobial Activity in Cocultures

The soil bacterium Burkholderia thailandensis produces 2-alkyl-4(1 H )-quinolones that are mostly methylated 4-hydroxyalkenylquinolines, a family of relatively unstudied metabolites similar to molecules also synthesized by Pseudomonas aeruginosa . Several of the methylated 4-hydroxyalkenylquinolines have antimicrobial activity against other species. We show that Bacillus subtilis strain 168 is particularly susceptible to N -oxidated methylalkenylquinolines (HMAQ-NOs). We confirmed that HMAQ-NO biosynthesis requires the previously unstudied protein HmqL. These results provide new information about the biology of 2-alkyl-4(1 H )-quinolones, particularly the methylated 4-hydroxyalkenylquinolines, which are unique to B. thailandensis . This study also has importance for understanding B. thailandensis secondary metabolites and has implications for potential therapeutic development.