Proteomics-based analysis reveals that Verticillium dahliae toxin induces cell death by modifying the synthesis of host proteins

Verticillium dahliae is one of the most destructive soil-borne fungal pathogens that cause vascular wilt diseases in a wide range of important crop plants, including cotton. However, the mechanisms used by this pathogen to infect cotton have not been fully elucidated. In the present study, we first investigated changes in protein abundance during the initial interaction between cotton roots and V. dahliae. Among the proteins that were upregulated upon infection, some were related to reactive oxygen species (ROS); among those downregulated upon infection were proteins involved in normal metabolism or cell structure. Further experiments confirmed that a sudden release of ROS and cell death accompany V. dahliae infection in the cotton vasculature. Further analysis indicated that a culture supernatant of V. dahliae induced lesion formation in tobacco leaves; de novo protein synthesis not active gene expression was required for this induction. Lesion formation was dependent on the age of leaves, but neither the known ROS burst nor the ubiquitin/26S proteasome system are prerequisites.