DspEAvrE

DspEAvrE is a bacterial effector protein identified in the phytopathogenic bacterium Pseudomonas syringae. It belongs to the AvrE family of type III secretion system (T3SS) effectors, which are secreted directly into host plant cells where they manipulate cellular processes to promote bacterial virulence. The gene encoding DspEAvrE is located in a mobile genetic element that can be transferred between strains, contributing to the rapid spread of virulence traits within Pseudomonas populations.

The protein contains an N‑terminal helix‑turn‑helix motif and a central domain rich in acidic and glycine residues that is predicted to be involved in protein‑protein interactions. The C‑terminal region includes a conserved hydrophobic motif that is essential for membrane localization in infected plant cells. Structural modeling suggests that DspEAvrE adopts a compact fold with a surface pocket capable of binding host phospholipids. Functional studies in Arabidopsis and tomato have shown that overexpression of DspEAvrE leads to increased susceptibility to bacterial wilt and reduced stomatal closure, indicating its role in subverting plant innate immunity.

Mutagenesis experiments reveal that the catalytic triad (Asp-His-Ser) within DspEAvrE is required for its virulence activity, although the precise enzymatic function remains unclear. In addition, proteomic analyses have identified host targets of DspEAvrE, including components of the cytoskeletal network and signaling kinases, suggesting that the effector disrupts cytoskeletal dynamics and interrupt signal transduction pathways. In vitro assays demonstrate that purified DspEAvrE displays ATPase activity, which may contribute to its role in cellular energy management during infection.

DspEAvrE is thus a multifunctional virulence protein that interferes with host defense responses, aids in bacterial colonization, and enhances disease development. Ongoing research aims to elucidate its exact enzymatic mechanisms and to identify potential targets for developing resistant crop varieties.