Interception of the fungal haustorium by the plant broad-spectrum resistance protein RPW8 (II)

University Of Maryland, College Park, College Park MD

Investigators

Abstract

Many fungal and oomycete pathogens invade plants with a specialized infection structure named the haustorium, which derives nutrients from the host cell and is a mechanism by which pathogens can cause serious plant diseases. In response, plants have evolved elaborate defense mechanisms to fight against such infection. Mechanisms of host-pathogen recognition and defense signaling have been extensively studied; however, very little is known about the mechanisms of molecular warfare at the host-pathogen structural interface known as the extra-haustorial membrane (EHM). The investigators discovered that RPW8, a protein conferring broad-spectrum resistance against powdery mildew in the plant Arabidopsis , is specifically targeted to the EHM, which encases the haustorium of powdery mildew ; in this location, RPW8 activates defenses to constrain the haustorium. Using a combination of mutational, cell biological, genetic and biochemical approaches, the investigators aim in this project to understand how RPW8.2 activates this resistance. Specifically, the investigators will define functionally important motifs and individual amino acids in RPW8.2, identify the trafficking cues for targeting RPW8.2 to the EHM, and characterize the role of a protein phosphatase type 2C in regulation of RPW8.2-mediated defense. Results from this project will not only elucidate the molecular basis of RPW8.2-mediated broad-spectrum mildew resistance but also provide fresh mechanistic insight into targeted protein trafficking as a critical component of plant innate immunity. Haustorium-forming fungal and oomycete pathogens pose constant threats to the world's food security. Discoveries from this project will help engineer novel resistance strategies against these pathogens , with the potential for improved crop production and environmental protection. This project will provide science training and research opportunities for high school and undergraduate students, especially those from under-representative groups; it will also provide extensive research training for one graduate student and one postdoctoral associate to prepare them for careers in science.