Plants and animals rely on innate immunity to prevent potential infections by detection of pathogen-associated molecular patterns (PAMPs) through pattern recognition receptors (PRRs). In plants, PAMPs are perceived by cell-surface PRRs and mount PAMP- triggered immunity (PTI). Successful pathogens are able to suppress PTI by producing virulence effectors, which, in turn, are recognized by plant intracellular PRRs to initiate effector-triggered immunity (ETI). This complex host-microbe interaction is intricately intertwined with a wide range of environmental factors. For example, we found that the ambient temperature fluctuation regulates PTI and ETI in a distinct manner. We have developed an Arabidopsis cell system to express individual pathogen effectors for ETI or treat cells with purified PAMPs for PTI. In combination with enriched genetic and genomic resources in Arabidopsis, this synchronized and autonomous plant cell-single pathogen signal system holds significant promise for dissecting the complex regulation of signaling events in ETI and PTI. Our preliminary data strongly suggest the existence of differential early signaling mechanisms underlying two branches of plant innate immunity. In particular, we found that the specific members of a large gene family encoding calcium-dependent protein kinases (CDPKs) play pivotal roles in transducing calcium signature in ETI. Our proposed research will employ a multifaceted approach to further understand the signaling mechanisms underlying plant ETI and PTI.
The Specific Aims for this application are the following: 1) Decipher the distinct and convergent gene regulation in ETI and PTI;2) Elucidate the functions of CDPKs in ETI signaling;3) Dissect the ambient temperature regulation of innate immunity. Plant PTI and ETI are most similar to "Toll-like receptor" and "NOD-like receptor" innate immune signaling pathways in mammals respectively. Thus, our research will contribute to a general understanding of innate immunity and improve our ability to prevent and control infectious diseases.

Public Health Relevance

Understanding the intricately intertwined signal transduction networks acting downstream of various host immune sensors could provide novel avenues to prevent and control infectious diseases. Given that plant cell-surface and intracellular immune sensors are most similar to "Toll-like receptor" and "NOD-like receptor" in mammals respectively, our research will have broad impact on the understanding of signaling mechanisms of animal innate immunity.

Agency
National Institute of Health (NIH)
Institute
National Institute of General Medical Sciences (NIGMS)
Type
Research Project (R01)
Project #
5R01GM092893-04
Application #
8416398
Study Section
Molecular and Integrative Signal Transduction Study Section (MIST)
Program Officer
Dunsmore, Sarah
Project Start
2010-04-01
Project End
2015-01-31
Budget Start
2013-02-01
Budget End
2014-01-31
Support Year
4
Fiscal Year
2013
Total Cost
$242,859
Indirect Cost
$75,195
Name
Texas A&M University
Department
Biochemistry
Type
Schools of Earth Sciences/Natur
DUNS #
078592789
City
College Station
State
TX
Country
United States
Zip Code
77845
Wu, Shujing; Shan, Libo; He, Ping (2014) Microbial signature-triggered plant defense responses and early signaling mechanisms. Plant Sci 228:118-26
Zhou, Jinggeng; He, Ping; Shan, Libo (2014) Ubiquitination of plant immune receptors. Methods Mol Biol 1209:219-31
Zhou, Jinggeng; Wu, Shujing; Chen, Xin et al. (2014) The Pseudomonas syringae effector HopF2 suppresses Arabidopsis immunity by targeting BAK1. Plant J 77:235-45
Lin, Wenwei; Li, Bo; Lu, Dongping et al. (2014) Tyrosine phosphorylation of protein kinase complex BAK1/BIK1 mediates Arabidopsis innate immunity. Proc Natl Acad Sci U S A 111:3632-7
Li, Fangjun; Cheng, Cheng; Cui, Fuhao et al. (2014) Modulation of RNA polymerase II phosphorylation downstream of pathogen perception orchestrates plant immunity. Cell Host Microbe 16:748-58
Gao, Xiquan; Li, Fangjun; Li, Maoying et al. (2013) Cotton GhBAK1 mediates Verticillium wilt resistance and cell death. J Integr Plant Biol 55:586-96
Cui, Fuhao; Wu, Shujing; Sun, Wenxian et al. (2013) The Pseudomonas syringae type III effector AvrRpt2 promotes pathogen virulence via stimulating Arabidopsis auxin/indole acetic acid protein turnover. Plant Physiol 162:1018-29
Cheng, Cheng; Gao, Xiquan; Feng, Baomin et al. (2013) Plant immune response to pathogens differs with changing temperatures. Nat Commun 4:2530
Lin, Wenwei; Ma, Xiyu; Shan, Libo et al. (2013) Big roles of small kinases: the complex functions of receptor-like cytoplasmic kinases in plant immunity and development. J Integr Plant Biol 55:1188-97
Gao, Xiquan; He, Ping (2013) Nuclear dynamics of Arabidopsis calcium-dependent protein kinases in effector-triggered immunity. Plant Signal Behav 8:e23868

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