Grant: Discovery Grants Program - Individual

Plant diseases caused by infectious agents such as fungi, oomycetes, bacteria and viruses have a devastating impact on agricultural production and food supply every year. In response to pathogen attack, plants however, have evolved a variety of physical and chemical defenses to ward off attempted invasions. On the plant surface, attempted pathogen invasion is often accompanied by focal deposition of cell wall appositions (CWAs) made of lignin, callose and structural proteins underneath the penetration site. Cell wall reinforcement-mediated penetration resistance has long been recognized as one of the most prominent facets of plant basal defense responses, irrespective of compatible or incompatible interaction. Several genes and genetic pathways have been previously identified to contribute to penetration resistance, including major PENETRATION (PEN) genes (PEN1, PEN2, PEN3, PEN4). However, the cellular pathways and signaling mechanisms regulating the biosynthesis and deposition of CWAs at the pathogen penetration site remain largely unknown. One core aspect of my research program has been devoted to understanding the molecular and cellular mechanisms of penetration resistance in plants against fungal pathogen attack. Using the Arabidopsis-powdery mildew pathosystem, we have recently shown that the dynamic assembly and rearrangement of the actin cytoskeleton and the trans-Golgi network (TGN) mediate intracellular trafficking that contributes to the deposition of CWAs and penetration resistance. In proposed research, we will explore the additional critical host components and their functions in modulating CWAs with two main objectives: (A) to understand the biosynthesis and polymerization of monolignols at CWAs underneath the pathogen penetration site, and (B) to decipher the role of Ca2+ homeostasis and signaling in regulation of CWAs in penetration resistance. We will take a systems biology approach along with high throughput and classical plant pathology techniques to achieve these objectives. This research will lead to significant advancements in the understanding of plant defense mechanisms against pathogen attack, thus facilitating the development of durable disease resistant crops against a broader spectrum of plant pathogens.