To explore the molecular structure of attachment genes, we constructed and characterized a new arabinose-inducible vector for the high-attachment strain Stenotrophomonas AGS-1 isolated from aerobic granular sludge (AGS). mCherry was used as a simple observation biomarker, and the araC-PBAD-inducible promoter was chosen to artificially regulate the expression of target genes. The system achieved little leaky basal expression and high maximal induced expression. The araC-PBAD-based inducible expression was modulated over a wide range of 0.0005 to 0.2% l-arabinose. Notably, a "lag expression" phenomenon was observed in which mCherry was expressed after bacterial growth in LB medium. Using the system and the strategy of fusion expression of target genes (rmlA and AsCas12a) plus mCherry, the recombinant AGS-1 strain achieved the effective induction of rmlA and AsCas12a-mCherry gene expression in the range of 0.0005 to 0.1% l-arabinose. These results demonstrate that the new arabinose-inducible vector could be used as an important molecular tool in the gene function and genome-editing research of strain AGS-1.
Keywords: AGS-1; araC-PBAD vector; fusion plasmid; inducible expression; mCherry.