The Verticillium longisporum phospholipase VlsPLA2 is a virulence factor targets host nuclei and modulates plant immunity

Abstract

Phospholipases A2 (PLA2) are lipolytic enzymes, responsible for phospholipids hydrolysis. The role of PLA2 in various aspects of cell physiology has been shown, but their involvement in host-microbe interactions remains to be elucidated. The present study investigated the biological function of the secreted VIsPLA2 phospholipase in the phytopathogenic fungus Verticillium longisporum with emphasis on its role in host-microbe interactions. The VlsPLA2 was highly induced in V. longisporum during interaction with host plant Brassica napus, encoding an active phospholipase A2. VlsPLA2-overexpression V. longisporum strain showed an increased virulence on Arabidopsis plants, plausibly by inducing virulence factors. Furthermore, VIsPLA2 are transported to the nucleus, by hijacking VAMPA proteins, causing suppression of PTI-induced hypersensitive response, possibly by modulating the expression of genes involved in plant immunity. In summary, VlsPLA2 acts as a virulence factor by hydrolyzing the hosts nuclear envelope phospholipids, an action that induces signaling cascade, suppressing basal plant immunity responses.