EAGER: Plant chromatin remodeling in response to the bacterial pathogen Pseudomonas syringae

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This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5).The plant innate immune system represents an important barrier that microbial pathogens need to circumvent in order to cause disease. Evidence in the literature suggests that host transcriptional activity in response to pathogen stress is at least partly controlled by the modification of proteins called histones that organize DNA. However, these pathogen-induced processes are not well understood and have not been adequately explored. The bacterial plant pathogen Pseudomonas syringae injects proteins called type III effectors (T3Es) into plant cells, and it requires these to be pathogenic. It now appears that the majority of P. syringae T3Es contribute to disease in plants primarily by suppression of plant immunity. It seems plausible that T3Es alter the modifications of histones, which would alter plant transcription. Identifying innate immune responses that are under this type of control and the extent that T3Es can alter these modifications will lead to a better understanding of bacterial pathogenic strategies, and it may reveal new components of the ability of the host to remodel their chromatin to favor gene expression. The objective of this project is to determine if chromatin remodeling occurs in response to different P. syringae strains and if T3Es can alter these modifications. To investigate chromatin remolding several different assays including chromatin immunoprecipitation (ChIP) assays and ChIP assays followed by pyrosequencing (ChIP-Seq) to identify plant genes that are under epigenetic control in response to biotic stress. The long term goal of this research is to better understand the plant innate immune system and engineer plants that are more resistant to microbial pathogens. Broader impacts: The project would have many of the broader impacts present in a standard NSF project including the training of undergraduate and graduate students. However, because Co-PI van Dijk is in the Biology Department at Creighton University, which is primarily an undergraduate institution, she will be able to reach many more undergraduates. These students do not have as many research opportunities as students attending research universities. The PIs have established an informal program where an undergraduate from the van Dijk laboratory at Creighton spends the summer working in the Alfano laboratory at the University of Nebraska. This project will allow us to scale-up this undergraduate summer research experience to reach more students. In addition, these students will return back to Creighton to continue their research projects in the van Dijk laboratory.