Probing the molecular mechanisms for pristinamycin yield enhancement in Streptomyces pristinaespiralis.

The mechanisms for the enhancement of pristinamycin production in the high-yielding recombinants of Streptomyces pristinaespiralis obtained by genome shuffling were investigated by quantitative real-time PCR (Q-PCR) and amplified fragment length polymorphism (AFLP) techniques. Q-PCR analysis showed that snaB and snbA involved, respectively, in the biosynthesis of pristinamycins II and I component had more extended high expression in the recombinant than that in the ancestor during fermentation process, indicating their expression changes might be key factors during the biosynthesis of the antibiotic. In addition, the antecedent establishment of the high self-resistance to pristinamycin, because ptr resistance gene started high-level expression ahead of the onset of the antibiotic production in the recombinant, might also lead to the increase of the antibiotics yield. AFLP analysis of these recombinants revealed genome variation of two novel genes, the homologs of AfsR regulatory gene and transposase gene, indicating these two gene variations were probably responsible for yield improvement of pristinamycin. This study provided several potential molecular clues for pristinamycin yield enhancement.