Abstract
Type IV secretion systems (T4SS) can mediate the translocation of bacterial virulence proteins into host cells. The plant pathogen Agrobacterium tumefaciens uses a T4SS to deliver a VirD2-single stranded DNA complex as well as the virulence proteins VirD5, VirE2, VirE3, and VirF into host cells so that these become genetically transformed. Besides plant cells, yeast and fungi can efficiently be transformed by Agrobacterium. Translocation of virulence proteins by the T4SS has so far only been shown indirectly by genetic approaches. Here we report the direct visualization of VirE2 protein translocation by using bimolecular fluorescence complementation (BiFC) and Split GFP visualization strategies. To this end, we cocultivated Agrobacterium strains expressing VirE2 tagged with one part of a fluorescent protein with host cells expressing the complementary part, either fused to VirE2 (for BiFC) or not (Split GFP). Fluorescent filaments became visible in recipient cells 20–25 h after the start of the cocultivation indicative of VirE2 protein translocation. Evidence was obtained that filament formation was due to the association of VirE2 with the microtubuli.
Highlights
The gram-negative plant pathogen Agrobacterium tumefaciens provokes crown gall tumor formation in dicotyledonous plant species by their genetic transformation with a set of oncogenic genes
We used the virulence protein VirE2 in our studies because of its abundance and because it has been shown that it self-associates in the absence of its chaperone VirE1, which is present in Agrobacterium, but which is not translocated into host cells
Prior to investigating VirE2 translocation from Agrobacterium to yeast we studied the localization of VirE2 fusions in yeast cells as has been done before in plant cells
Summary
The gram-negative plant pathogen Agrobacterium tumefaciens provokes crown gall tumor formation in dicotyledonous plant species by their genetic transformation with a set of oncogenic genes. The DNA is translocated in a single-stranded form (T-strand) from the pathogen into the host cells. Expression of the T-DNA genes in plant cells leads to the synthesis of plant hormones causing uncontrolled cell proliferation and results in crown gall tumor formation (Gelvin 2003). Under conditions that induce the virulence system A. tumefaciens is able to transform non-plant organisms such as yeast and fungi (Bundock et al 1995; Bundock and Hooykaas 1996; Piers et al 1996; De Groot et al 1998). For many plant and fungal species Agrobacterium-mediated transformation (AMT) has become the preferred method of transformation
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
