April Hagemeister

Group members: Jasmine Do, Hannah Littel, Emma Manick, Christina Meleck, Nathan Murphy, and Srivats Yerraguntala

Plants use two modes of innate immunity to fend off pathogens: PTI (pattern-triggered immunity) and ETI (effector-triggered immunity). Due to the complexity of ETI signaling, there is a limited understanding of the components and processes involved in ETI. Past research discovered four signaling sectors that mediate ETI signaling: JA, ET, PAD4 and SA and are controlled by DDE2, EIN2, PAD4, and SID2 gene products, respectively. After removal of the four immune signaling sectors, only the reintroduction of the PAD4 sector restores the majority of the plant ETI response capabilities. The objective of this project is to study the unknown molecular components involved in the PAD4 immune signaling sector in Arabidopsis thaliana, when ETI is triggered by the Pseudomonas syringae strain expressing AvrRpt2 effector protein (D36E AvrRpt2). A chemically mutagenized population of an A. thaliana dde2 ein2 sid2 mutant have been used to ensure that other immune signaling sectors, excluding PAD4, are not involved in the plant immune response. Second generation mutantagenized plants are infiltrated with D36E AvrRpt2. Mutant phenotypes that fail to demonstrate an ETI response (a hypersensitive response; HR) are likely to be mutated in genes involved in the PAD4 sector. Therefore, seeds of those mutants of interest will be collected and be used for backcrossing to the starting dde2 ein2 sid2 mutant. The novel genes will be mapped in the A. thaliana genome using bulk segregant sequence analysis. This work will contribute to a better understanding of the role of the signaling sector PAD4 in ETI.