The novel approach we have described permits, for the first time, the elucidation of gene function for a major group of biologically and medically important parasites, which in the example presented here provides non-intuitive results linking parasite secretions to host cell signalling.
Calpain cleaves a large number of host proteins, particularly proteins involved in host focal adhesions and cytoskeletal events and indeed calpain activity has been linked to cell migration and cell detachment (Glading et al., 2002).
More than 80% (34 out of 42) of the SA-response targets are also associated with the GO term 'cell death', suggesting that WRKY33 repression of the SA pathway is linked to modulation of host cell death responses.
Some of these events most likely involve host cell proteins, and reverse transcription has been linked to several cell factors (reviewed in [9], [34]).
The protein, covalently linked to the cell wall, is subsequently displayed on the bacterial surface, facilitating functions in host-pathogen interaction [10], [11].
Moreover, T3SEs are often multifunctional proteins with many overlapping properties that orchestrate specific host cell responses, which ultimately subvert fundamental pathways linked to cell survival, inflammation and microbe destruction (Dean, 2011).
Recent studies have demonstrated that ER stress can also elicit an innate immunity defense to protect tissues in mammalian cells, and in plant cells, ER stress is linked to the host defense response to microbial infections [ 10- 12].
This validates our interpretation of the above finding – that the rapid disruption of TER by the tir mutant that is linked to cell detachment and necrosis can be prevented by pre-delivery of Tir into host cells.
Certain species group together, and this grouping is again linked to related host plant species.
