Innate Immunity is the most ancient and evolutionarily conserved central defense system that distinguishes host-self from non-self microbial pathogens in plants, animals and humans. It provides the first line of inducible defense against infectious diseases and underlies the prevention of constant and omnipresent microbial invasion. A key function of innate immunity is the detection of microbe-associated molecular patterns (MAMPs, such bacterial flagellin) by pattern recognition receptors and the launch of appropriate defense responses. Recent discoveries have revealed remarkable convergent evolution in the recognition of diverse MAMPs by leucine-rich-repeat receptors and the activation of multiple MAPK cascades in plants, animals and humans. Despite the universal and essential involvement of MAPK cascades in mediating MAMP signaling in plants, worms, flies, mammals and humans, the molecular mechanisms underlying the intertwined signaling webs remain mostly elusive due to the complexity of functional redundancy, mutant lethality and shared components in distinct signaling pathways. The goal of this research project is to establish a regulatory framework for the convergent MAMP signaling using Arabidopsis thaliana as a model system. The proposed experiments aim to integrate molecular, biochemical, cellular, genetic, and genomic approaches to dissect the multifunctional BAK1-MAPKKK complexes and MAPKK-MAPK cascades, and to analyze the downstream WRKY transcription factors in controlling diverse target genes in plant defense responses. Specifically, the project will focus on characterizing and integrating the functions of 15 Arabidopsis genes in flagellin signaling using cell- based assays, transgenic plants and loss-of-function mutants with specific defects in the flagellin receptor FLS2, receptor signaling partner BAK1, MAPKKK-MAPKK-MAPK cascades and WRKY transcription factors. Protein interaction, phosphorylation and ubiquitination assays, quantitative RT- PCR, whole-genome microarray and chromatin-immunoprecipitation will be carried out to elucidate the key and conserved signaling mechanisms in plant innate immunity.
Three Specific Aims are:
Aim 1. Analyze interactions and regulations of BAK1-MAPKKK signaling complexes Aim 2. Dissect the MAPKK-MAPK cascade functions in convergent MAMP signaling Aim 3. Define functions and regulations of WRKY transcription factors.

Public Health Relevance

The powerful innate immune system underlies the prevention of constant and omnipresent microbial invasion, and provides the first line of inducible defense against infectious diseases in plants, animals and humans. A key function of innate immunity is the detection of microbe- associated molecular patterns (MAMPs) and the launch of appropriate defense responses. Recent discoveries have revealed remarkable convergent evolution in MAMP perception by leucine-rich- repeat pattern recognition receptors and the activation of multiple MAPK cascades. The proposed research from receptor kinase signaling complexes to intertwined MAPK cascades and WRKY transcriptional controls will discover novel and fundamental molecular mechanisms in innate immune signaling, and provide innovative tools for future improvement of agriculture, environment and renewable energy production, as well as human health in treating infectious, inflammatory and autoimmune diseases.

Agency
National Institute of Health (NIH)
Institute
National Institute of General Medical Sciences (NIGMS)
Type
Research Project (R01)
Project #
2R01GM070567-05
Application #
7730350
Study Section
Cellular Signaling and Regulatory Systems Study Section (CSRS)
Program Officer
Marino, Pamela
Project Start
2004-04-01
Project End
2013-05-31
Budget Start
2009-08-01
Budget End
2010-05-31
Support Year
5
Fiscal Year
2009
Total Cost
$373,023
Indirect Cost
Name
Massachusetts General Hospital
Department
Type
DUNS #
073130411
City
Boston
State
MA
Country
United States
Zip Code
02199
Shi, Lin; Wu, Yue; Sheen, Jen (2018) TOR signaling in plants: conservation and innovation. Development 145:
Li, Zhenxiang; Zhang, Dandan; Xiong, Xiangyu et al. (2017) A potent Cas9-derived gene activator for plant and mammalian cells. Nat Plants 3:930-936
Chung, Hoo Sun; Sheen, Jen (2017) MAPK Assays in Arabidopsis MAMP-PRR Signal Transduction. Methods Mol Biol 1578:155-166
Liu, Kun-Hsiang; Niu, Yajie; Konishi, Mineko et al. (2017) Discovery of nitrate-CPK-NLP signalling in central nutrient-growth networks. Nature 545:311-316
Kim, Hyeon-Ji; Wu, Chung-Yi; Yu, Hui-Ming et al. (2017) Dual CLAVATA3 Peptides in Arabidopsis Shoot Stem Cell Signaling. J Plant Biol 60:506-512
Li, Lei; Sheen, Jen (2016) Dynamic and diverse sugar signaling. Curr Opin Plant Biol 33:116-125
Cheng, Zhenyu; Li, Jian-Feng; Niu, Yajie et al. (2015) Pathogen-secreted proteases activate a novel plant immune pathway. Nature 521:213-6
Li, Jian-Feng; Zhang, Dandan; Sheen, Jen (2015) Targeted plant genome editing via the CRISPR/Cas9 technology. Methods Mol Biol 1284:239-55
Xiong, Yan; Sheen, Jen (2015) Novel links in the plant TOR kinase signaling network. Curr Opin Plant Biol 28:83-91
Hamel, Louis-Philippe; Sheen, Jen; Séguin, Armand (2014) Ancient signals: comparative genomics of green plant CDPKs. Trends Plant Sci 19:79-89

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