RT Journal Article SR Electronic(1) A1 Breton, Marc A1 Sagné, Evelyne A1 Duret, Sybille A1 Béven, Laure A1 Citti, Christine A1 Renaudin, JoëlYR 2010 T1 First report of a tetracycline-inducible gene expression system for mollicutes JF Microbiology, VO 156 IS 1 SP 198 OP 205 DO https://doi.org/10.1099/mic.0.034074-0 PB Microbiology Society, SN 1465-2080, AB Inducible promoter systems are powerful tools for studying gene function in prokaryotes but have never been shown to function in mollicutes. In this study we evaluated the efficacy of the tetracycline-inducible promoter Pxyl/tetO2 from Bacillus subtilis in controlling gene expression in two mollicutes, the plant pathogen Spiroplasma citri and the animal pathogen Mycoplasma agalactiae. An S. citri plasmid carrying the spiralin gene under the control of the xyl/tetO2 tetracycline-inducible promoter and the TetR repressor gene under the control of a constitutive spiroplasmal promoter was introduced into the spiralin-less S. citri mutant GII3-9a3. In the absence of tetracycline, expression of TetR almost completely abolished expression of spiralin from the xyl/tetO2 promoter. Adding tetracycline (>50 ng ml−1) to the medium induced high-level expression of spiralin. Interestingly, inducible expression of spiralin was also detected in vivo: in S. citri-infected leafhoppers fed on tetracycline-containing medium and in S. citri-infected plants watered with tetracycline. A similar construct was introduced into the M. agalactiae chromosome through transposition. Tetracycline-induced expression of spiralin proved the TetR-Pxyl/tetO2 system to be functional in the ruminant pathogen, suggesting that this tetracycline-inducible promoter system might be of general use in mollicutes., UL https://www.microbiologyresearch.org/content/journal/micro/10.1099/mic.0.034074-0