Plants have evolved multi-layered resistance mechanisms to fight against pathogens. Research in the Xiao Lab is focused on understanding molecular mechanisms of plant broad-spectrum resistance mediated by RPW8 against powdery mildew fungi. RPW8 is an atypical resistance protein identified in Arabidopsis that is specifically targeted to the extra-haustorial membrane—the enigmatic host-pathogen interface, where RPW8 activates defenses to constrain the fungal feeding structure, i.e. the haustorium. Ongoing research projects address  (i) how RPW8 is targeted to, and activates defenses, at the host-pathogen interface; (ii) the origin & biogenesis of the extra-haustorial membrane and its role in host defense and fungal pathogenesis; (iii) pathogenicity mechanisms of powdery mildew fungi; and (iv) development of novel & host-pathogen-interface–focused resistance against haustorium-forming pathogens in plants.

The Arabidopsis  protein RPW8  confers broad-spectrum disease resistance to powdery mildew fungi. (1) Arabidopsis plants lacking RPW8 is susceptible to an adapted powdery mildew strain Golovinomyces cichoracearum UCSC1; (2) Arabidopsis plants expressing RPW8 are resistant to the pathogen and RPW8 is targeted to the extrahaustorial membrane where it activates defenses to constrain the fungal haustorium.