Graduate Research Assistant Iowa State University Ames, Iowa
Body of Abstract: Protein acetylation is a major post-translational modification that modulates many cellular processes, including plant immunity and stress responses. Cochlibolus carbonum (Northern Corn Leaf Spot) produces the effector HC-Toxin, a lysine deacetylase inhibitor required for pathogen virulence. RAMOSA1 ENHANCER LOCUS2 (REL2) is a transcriptional corepressor homologous to TOPLESS (TPL) in Arabidopsis. TPL family membersare required for various biological processes, including development and immunity, and are critical components of hormone responses, including auxin and jasmonate signaling pathways. We identified a lysine acetylation site on REL2 using global acetylome profiling of maize treated with HC-Toxin or C. carbonum. Furthermore, we found that rel2 loss of function mutant plants are susceptible to infection, demonstrating that REL2 is directly related to plant immunity. Using Yeast Two-Hybrid assays, we have shown REL2 that mimics acetylation results in reduced interaction of REL2 with transcription factors containing DLN and RLFGV repression motifs. We have further confirmed REL2 as a corepressor using luciferase corepression assays. Additionally, we have generated a transcriptomic data set from rel2 and WT plants treated with HC-Toxin and C. carbonum and identified a list of differentially expressed genes (DEGs). Lastly, we have created a model of REL2 transcriptional regulation during pathogen and hormone response. This work aims to elucidate how hyperacetylation impacts the biological activity of REL2 and REL2’s roles in plant-pathogen interactions.