Objective   Genes relating to prodigiosin synthesis in Serratia plymuthica ACCC 02146 were identified, and a transposon mutant library on the strain constructed.

  Methods  Fifteen prodigiosin-producing microbes were obtained from a conservation center and a laboratory. After identification by 16S rRNA gene sequencing, they were classified according to the neighbor-joining trees. Promoter sequences of prodigiosin synthesis gene were analyzed, and color producing capacity of the individual strains evaluated. Selected strain was cloned and further studied to establish a library on the transposon mutants.

  Results   Differed from other strains in terms of 16S rDNA and promoter sequences of the prodigiosin biosynthesis gene clusters, S.plymuthica ACCC 02146 was selected to clone the candidate gene for further investigation. A transposon mutant library was constructed subsequently. In the library, of 74 mutants showing significant variations in prodigiosin-producing ability, 25 had the insertions in pigA, pigB, pigC, pigD, and pigH, while 49 in the genes outside the cluster. On color formation, 6 strains with the mutation on maltose o-acetyltransferase gene, 4 on dihydroorotate dehydrogenase gene, 3 on MarR family of transcription factor SlyA genes, 3 on two-component transcriptional regulator RstA of the winged helix family, 3 on NAD(P)H-quinone oxidoreductase subunit I gene, 3 on NADH-quinone oxidoreductase, chain G gene, 3 on peptidylprolyl isomerase B gene, and one to two on other genes were found possibly related to significant alterations on the prodigiosin production as well.

  Conclusion  Aside from the identified specific clusters of prodigiosin synthesis-associated genes, additional factors in the forms of enzymes, transcriptional regulators, and/or structural proteins were now speculated to also directly or indirectly contribute in varying degrees to the prodigiosin synthesis in Serratia sp.