The plant pathogen Agrobacterium tumefaciens carries a virulence gene system that is required for the initiation of crown gall tumors on susceptible plants. Expression of the vir genes is activated by the VirA/VirG two component regulatory system. VirA is a histidine kinase which signals the presence of certain chemicals found at the site of a plant wound. The receiver domain located at its carboxyl terminus defines VirA as a hybrid histidine kinase. Here, we show that the VirA receiver interacts with the DNA-binding domain of VirG. This finding supports the hypothesis that the receiver acts as a recruiting factor for VirG. In addition, we show that removal of the VirA receiver allowed vir gene expression in response to glucose in a dose dependent manner, indicating that the receiver controls VirG activation and suggesting that the supplementary ChvE-sugar signal increases this activity.
Wise, A. A., & Binns, A. N. (2016). The receiver of the Agrobacterium tumefaciens VirA histidine kinase forms a stable interaction with VirG to activate virulence gene expression. Frontiers in Microbiology, 6(JAN). https://doi.org/10.3389/fmicb.2015.01546