Production of P2D1 tailocins byDickeya dadantii3937: a temporal relationship between the stressor onset, gene expression, and the concentration of active particles

Abstract

Tailocins are bacteriocins resembling bacteriophage tails. Previously, we reported the production of P2D1 tailocins in the plant pathogen Dickeya dadantii 3937, the synthesis of which was upregulated upon treatment with mitomycin C. In the current study, we characterized the temporal relationship between the inducer onset, activation of expression of tailocin-related genes, the concentration of tailocin particles, and the titer of viable producer cells. Using a newly established RT-qPCR assay, we found that the expression of P2D1 structural genes peaks two hours after the addition of mitomycin C. Simultaneous measurement of the titer of tailocins showed that the maximum concentration of these particles in the culture supernatant was reached 6 hours post induction and remained stable till the termination of the experiment (18 hours). Progressing accumulation of tailocins between the second and the sixth-hour post mitomycin C treatment correlated with a sharp drop in the count of viable cells (ca. five orders of magnitude). This effect was related to the mechanism by which tailocins are released from the cells, which involves cell lysis. Our study is the first detailed analysis of the timing of events during P2D1 tailocin synthesis in Dickeya spp.