Effect of pII key nitrogen regulatory gene on strain growth and butenyl-spinosyn biosynthesis in Saccharopolyspora pogona

PII signal transduction proteins are widely found in bacteria and plant chloroplast, and play a central role in nitrogen metabolism regulation, which interact with many key proteins in metabolic pathways to regulate carbon/nitrogen balance by sensing changes in concentrations of cell-mediated indicators such as α-ketoglutarate. In this study, the knockout strain Saccharopolyspora pogona -Δ pII and overexpression strain S . pogona - pII were constructed using CRISPR/Cas9 technology and the shuttle vector POJ260, respectively, to investigate the effects on the growth and secondary metabolite biosynthesis of S . pogona . Growth curve, electron microscopy, and spore germination experiments were performed, and it was found that the deletion of the pII gene inhibited the growth to a certain extent in the mutant. HPLC analysis showed that the yield of butenyl-spinosyn in the S . pogona - pII strain increased to 245% than that in the wild-type strain while that in S . pogona -Δ pII decreased by approximately 51%. This result showed that the pII gene can promote the growth and butenyl-spinosyn biosynthesis of S . pogona. This research first investigated PII nitrogen metabolism regulators in S . pogona , providing significant scientific evidence and a research basis for elucidating the mechanism by which these factors regulate the growth of S . pogona , optimizing the synthesis network of butenyl-spinosyn and constructing a strain with a high butenyl-spinosyn yield. Key points • pII key nitrogen regulatory gene deletion can inhibit the growth and development of S. pogona. • Overexpressed pII gene can significantly promote the butenyl-spinosyn biosynthesis. • pII gene can affect the amino acid circulation and the accumulation of butenyl-spinosyn precursors in S. pogona.