Analysis of a new cluster of genes involved in the synthesis of the unique volatile organic compound sodorifen of Serratia plymuthica 4Rx13

The rhizobacterium Serratia plymuthica 4Rx13 emits the novel and unique volatile sodorifen (C16H26), which has a polymethylated bicyclic structure. Transcriptome analysis revealed that gene SOD_c20750 (annotated as terpene cyclase) is involved in the biosynthesis of sodorifen. Here we show that this gene is located in a small cluster of four genes (SOD_c20750 - SOD_c20780), and the analysis of the knockout mutants demonstrated that SOD_c20760 (annotated as methyltransferase) and SOD_c20780 (annotated as isopentenyl pyrophosphate (IPP) isomerase) are needed for the biosynthesis of sodorifen, while a sodorifen-negative phenotype was not achieved with the SOD_c20770 (annotated as deoxy-xylulose-5-phosphate (DOXP) synthase) mutant. Altogether, the function of this new gene cluster was assigned to the biosynthesis of this structurally unusual volatile compound sodorifen.