TOWARDS THE CHARACTERIZATION OF NOVEL C-DI-GMP EFFECTORS IN BDELLOVIBRIO BACTERIOVORUS

The predatory bacterium Bdellovibrio bacteriovorus has been proposed as a potential biocontrol tool against pathogens due to its predation upon a variety of Gram-negative bacteria. The complex, biphasic lifecycle of B. bacteriovorus is regulated by the secondary messenger cyclic diguanylic acid (c-di-GMP). C-di-GMP allosterically binds to receptor proteins that contain PilZ, nonfunctional GGDEF or EAL domains for signal transduction. Within the 3.8 Mb genome of B. bacteriovorus HD100 15 PilZ domain proteins that represent putative c-di-GMP receptors had been described. These data were updated recently, after identification in our laboratory (1) of 84 proteins as candidate c-di-GMP binders involved in numerous pathways including central and secondary metabolism, suggesting novel roles for c-di-GMP signaling in B. bacteriovorus. The aim of this research is to confirm c-di-GMP binding by novel effectors and its effects upon their output. Gene bd3610 encodes for a putative fibronectin type III protein that might be involved in attachment to the host cell, i.e. in the predatory process. In contrast, gene bd3897 encodes for the ATP-synthase F₀F₁ β subunit which together with γ and δ subunits are co-regulated under a single promoter. Both genes have been detected in a c-di-GMP-specific pulldown experiment (1). We will present data on our advances in the cloning, expression and characterization of c-di-GMP binding by these effectors.

(1)Rotem, Or, et al. Journal of Bacteriology (2015): JB-00422.