This project will further dissect the molecular and cellular basis of Xanthomonas campestris pathovar vesicatoria (Xcv) pathogenesis in plants. This bacterium uses a specialized secretory system to orchestrate cell-to-cell communication during the early stages of plant infection. The type III secretion system (TTSS) enables direct secretion and translocation of bacterial proteins into host plant cells. Once inside the host, TTSS effectors, acting presumably as virulence proteins, collectively modulate the cell to initiate disease symptoms in susceptible plants and to activate defense responses in resistant plants. To date, the mechanisms by which XcvTTSS effectors modulate plant physiology are virtually unknown. However, our work has provided important insights to the potential mechanisms used by the YopJ-like effectors, a family that is prevalent in Xanthomonas and conserved amongst plant and animal bacterial pathogens. Such conservation implies that pathogenic microbes use a specific mechanism to interfere with host cell signaling. We have shown that Xcv effectors in the YopJ and XopD family function as cysteine proteases inside plant and animal cells. The substrates for these effectors are highly conserved small ubiquitin-like modifiers (SUMO) that are covalently added to a number of regulatory proteins. Thus, we predict that YopJ-like effectors exert their pathogenic effect on host cells by disrupting posttranslational SUMO modification of proteins. ? ? The overall goal of this study is to identify and study the plant signal transduction pathways that are affected by the YopJ-like effector AvrBsT during Xanthomonas pathogenesis. Specifically, we will: (1) explore the effect of AvrBsT proteolysis on the SUMO pathway in Arabidopsis by isolating SUMOylated plant targets, (2) isolate the Arabidopsis bst disease resistance gene that provides protection against AvrBsT, and (3) use genetic screens to dissect the AvrBsTBST disease resistance signal transduction pathway in Arabidopsis. We believe our findings will reveal common mechanisms used by SUMO proteases conserved in both plant and animal pathogens to control eukaryotic physiology during bacterial-host interactions. ? ?

Agency
National Institute of Health (NIH)
Institute
National Institute of General Medical Sciences (NIGMS)
Type
Research Project (R01)
Project #
5R01GM068886-02
Application #
6950838
Study Section
Cell Development and Function Integrated Review Group (CDF)
Program Officer
Shapiro, Bert I
Project Start
2004-09-30
Project End
2009-08-31
Budget Start
2005-09-01
Budget End
2006-08-31
Support Year
2
Fiscal Year
2005
Total Cost
$273,000
Indirect Cost
Name
Stanford University
Department
Biology
Type
Schools of Arts and Sciences
DUNS #
009214214
City
Stanford
State
CA
Country
United States
Zip Code
94305
Kim, Jung-Gun; Stork, William; Mudgett, Mary Beth (2016) Quantification of Ethylene Production in Tomato Leaves Infected by Xanthomonas euvesicatoria. Bio Protoc 6:
Stork, William; Kim, Jung-Gun; Mudgett, Mary Beth (2015) Functional Analysis of Plant Defense Suppression and Activation by the Xanthomonas Core Type III Effector XopX. Mol Plant Microbe Interact 28:180-94
Fan, Min; Bai, Ming-Yi; Kim, Jung-Gun et al. (2014) The bHLH transcription factor HBI1 mediates the trade-off between growth and pathogen-associated molecular pattern-triggered immunity in Arabidopsis. Plant Cell 26:828-41
Magnani, Enrico; de Klein, Niek; Nam, Hye-In et al. (2014) A comprehensive analysis of microProteins reveals their potentially widespread mechanism of transcriptional regulation. Plant Physiol 165:149-59
Cheong, Mi Sun; Kirik, Angela; Kim, Jung-Gun et al. (2014) AvrBsT acetylates Arabidopsis ACIP1, a protein that associates with microtubules and is required for immunity. PLoS Pathog 10:e1003952
Kim, Jung-Gun; Stork, William; Mudgett, Mary Beth (2013) Xanthomonas type III effector XopD desumoylates tomato transcription factor SlERF4 to suppress ethylene responses and promote pathogen growth. Cell Host Microbe 13:143-54
Sonnewald, Sophia; Priller, Johannes P R; Schuster, Julia et al. (2012) Regulation of cell wall-bound invertase in pepper leaves by Xanthomonas campestris pv. vesicatoria type three effectors. PLoS One 7:e51763
Kim, Jung-Gun; Taylor, Kyle W; Mudgett, Mary Beth (2011) Comparative analysis of the XopD type III secretion (T3S) effector family in plant pathogenic bacteria. Mol Plant Pathol 12:715-30
Chen, Li-Qing; Hou, Bi-Huei; Lalonde, Sylvie et al. (2010) Sugar transporters for intercellular exchange and nutrition of pathogens. Nature 468:527-32
Kirik, Angela; Mudgett, Mary Beth (2009) SOBER1 phospholipase activity suppresses phosphatidic acid accumulation and plant immunity in response to bacterial effector AvrBsT. Proc Natl Acad Sci U S A 106:20532-7

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