Location: Emerging Pests and Pathogens ResearchTitle: Insights into the mechanisms of Promysalin, a secondary metabolite with genus-specific antibacterial activity against Pseudomonas
|Keohane, Colleen - EMORY UNIVERSITY|
|Steele, Andrew - EMORY UNIVERSITY|
|Wuest, William - EMORY UNIVERSITY|
Submitted to: International Conference on Pseudomonas
Publication Type: Abstract Only
Publication Acceptance Date: 6/29/2017
Publication Date: 9/1/2017
Citation: Giglio, K.M., Keohane, C.E., Steele, A.D., Wuest, W.M., Filiatrault, M.J. 2017. Insights into the mechanisms of Promysalin, a secondary metabolite with genus-specific antibacterial activity against Pseudomonas. International Conference on Pseudomonas. P57.
Technical Abstract: Promysalin, a secondary metabolite produced by Pseudomonas putida RW10S1, has antibacterial activity against a wide variety of Pseudomonas sp., including both human and plant pathogens. Promysalin induces swarming and biofilm formation in the producing species, and inhibits growth of susceptible species. P. putida KT2440, a non-producing strain is only mildly susceptible yet displays increased swarming in the presence of exogenous promysalin. In order to uncover mechanisms of promysalin action, we performed RNA-sequencing on P. putida KT2440 cells grown in the presence or absence of promysalin and analyzed changes in gene expression. RNA-sequencing results showed 455 differentially regulated genes in response to promysalin; 431 genes were downregulated and 22 were upregulated (FDR less than or equal to 0.05). Promysalin decreased expression of genes involved in flagella-mediated motility, and genes involved with iron storage and regulation, while expression of genes that function in transport either as multi-drug resistance efflux transporters or in the uptake of nutrients was increased in the presence of the compound. Our data provide insight into the mechanism of action of promysalin and indicate that 1) the increased swarming seen in promysalin-treated cells is not due to flagella-dependent motility; 2) promysalin-treated cells may be experiencing an iron-deficient environment; and 3) efflux transport may play a role in resistance to promysalin in species that are less susceptible. Additionally, we tested the effect of promysalin on the plant pathogen Pseudomonas syringae pv tomato DC3000 and found the IC50 value to be around 500 nM, indicating that promysalin may be an effective agent against this pathogen.