Poster abstracts
Poster number 39 submitted by Priscila Rodriguez Garcia
Identifying RIN4 amino acid motifs necessary for its function in plant immunity
Priscila M. Rodriguez Garcia (Department of Molecular Genetics; and Cellular, Molecular, and Biochemical Sciences Program, The Ohio Sate University), Hasung Kim (Plant immunity laboratory, Postech Biotech Center, Dept. of Life Sciences, Pohang University of Science and Technology, Republic of Korea), Keehoon Sohn (Plant immunity laboratory, Postech Biotech Center, Dept. of Life Sciences, Pohang University of Science and Technology, Republic of Korea), David Mackey (Department of Horticulture and Crop Science; Department of Molecular Genetics; Center for Applied Plant Sciences; and Cellular, Molecular, and Biochemical Sciences Program, The Ohio State Univeristy)
Abstract:
RPM1-interacting protein 4 (RIN4) is a central player in plant immunity. In Arabidopsis, RIN4 (AtRIN4) connects two major plant defense pathways – basal defense and nucleotide-binding leucine-rich repeats (NLR)-triggered immunity (NTI). Based on overexpression and mutation, AtRIN4 is a negative regulator of basal defenses. Upon perception of a pathogen challenge, plant-induced phosphorylation of AtRIN4 alleviates its suppression of basal defenses. However, adapted pathogens, like Pseudomonas syringae, inject effector proteins into the plant cell that alternatively modify AtRIN4 (phosphorylation of other residues, ADP-ribosylation, proteolysis) and thus enhance its ability to suppress basal defenses. This can produce a state of “effector-triggered susceptibility”. However, plants encode NLR resistance-proteins with the potential to recognize the presence of pathogen effectors and elicit NTI. In Arabidopsis we know of two NLR proteins that are activated upon modification of AtRIN4 by three unrelated effectors from P. syringae. Even though much in known about the identify of AtRIN4 modifications and their phenotypes, we still have a lot to uncover about their mechanism. In this study, I aim to identify AtRIN4 amino acid motifs necessary for: 1) its suppression of basal defenses, 2) its suppressive interaction with NLR proteins, and 3) its capacity to transduce effector-induced modifications into activation of NLR proteins. Previous studies have attempted to identify AtRIN4 motifs important for its functions by using deletion constructs. However, this approach interferes with other AtRIN4 functions like its subcellular localization, interacting proteins partners, potential intramolecular interactions, etc. I will use a collection of 27 RIN4 homologs from different plant species developed by our collaborators in Korea. These RIN4 homologs will allow for the identification of motifs with putative functions based on phenotypic and sequence differences between them. This study will provide a guide for altering motifs to produce RIN4 proteins that improve plant immunity. Since RIN4 homologs are found throughout the plant kingdom, understanding its mechanisms of action will aid in enhancing disease resistance in a wide range of economically important plants.
Keywords: plant, immunity, RIN4