Cytoskeletal regulation of immunity

Michigan State University, East Lansing MI

Investigators

Abstract

The ability of plants to respond to environmental threats – including both abiotic and biotic stress – requires the function of multiple cellular-genetic processes. Among these include processes that are not only associated with the immune system, but those also required for growth, development, reproduction and senescence. In this regard, plant immunity is not a narrowly defined process, but rather, a broader, integrated mechanism that uses the entire cell (and organism) to respond to pathogen infection. This research will ultimately define how plant stress signals are recognized, decoded, translated, and communicated to the whole plant. From this, insight into how signals from the outside are perceived and lead to the generation of genetically-encoded responses, internally, will be gained. The project employs a combination of microscopy-based techniques and biochemistry to uncover the signals that plants use to defend against pathogen infection. With this knowledge, the investigators will learn how plants determine if a signal is from a friend or a foe, and from this, determine how plants regulate the immune system. The ultimate goal of this research is to uncover the mechanisms that plants use to survive in environments where the threat of pathogen infection is high, and moreover, when environmental conditions favor the pathogen. The research team will also actively communicate to the public the link between basic research and agriculture. To do this, the scientists working on this project, including experts in heath and nutrition at Michigan State University will partner with the Lansing Capital Area library system to will educate young children – and their families – on topics related to food production and nutrition. As a key component of the surveillance function of the immune system of both plants and animals, the actin cytoskeleton is required for cellular response to a variety of pathogen-derived elicitors. Additionally, a role for actin is emerging which includes the coordinated regulation of cellular processes that signal host defense, resistance, susceptibility, and cell death. While conclusive evidence demonstrating that the plant cytoskeleton directly interacts with individual immune receptors is lacking, an abundance of data in mammalian systems does exist; this includes a role for the pathogen-recognition receptor nucleotide-binding oligomerization domain protein 1 (NOD1), which requires F-actin for proper PM localization. Further, the interaction(s) between NOD1 and actin serves as an immune interface which influences actin-remodeling and control of downstream signaling, including the phospho-dependent activation of the actin depolymerizing factor cofilin. This project will define the relationships that link the first line of plant defense (pattern-triggered immunity) to a complex and pervasive macromolecular structure – the cytoskeleton – to drive surveillance. The proposed research will contribute new insights in cell signaling across eukaryotic systems through the characterization and definition of the poorly understood mechanism by which cell structure and orchestration of pathogen recognition regulates signaling and immunity in plants. High school, undergraduate, graduate, and post-graduate students will be involved in the proposed work, and engage in cross-disciplinary training in the biological sciences utilizing traditional and contemporary methods necessary for success in modern biology. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.