title: The function of the Mediator complex in plant immunity.
abstract: Upon pathogen infection, plants undergo dramatic transcriptome reprogramming to shift from normal growth and development to immune response. During this rapid process, the multiprotein Mediator complex has been recognized as an important player to fine-tune gene-specific and pathway-specific transcriptional reprogramming by acting as an adaptor/coregulator between sequence-specific transcription factor and RNA polymerase II (RNAPII). Here, we review current understanding of the role of five functionally characterized Mediator subunits (MED8, MED15, MED16, MED21 and MED25) in plant immunity. All these Mediator subunits positively regulate resistance against leaf-infecting biotrophic bacteria or necrotrophic fungi. While MED21 appears to regulate defense against fungal pathogens via relaying signals from upstream regulators and chromatin modification to RNAPII, the other four Mediator subunits locate at different positions of the defense network to convey phytohormone signal(s). Fully understanding the role of Mediator in plant immunity needs to characterize more Mediator subunits in both Arabidopsis and other plant species. Identification of interacting proteins of Mediator subunits will further help to reveal their specific regulatory mechanisms in plant immunity.
authors.affiliation: Department of Microbiology and Cell Science; University of Florida; Gainesville, FL USA.
authors.forename: Chuanfu
authors.initials: C
authors.lastname: An
authors.forename: Zhonglin
authors.initials: Z
authors.lastname: Mou
mesh_terms: D000528:Alternaria; D017360:Arabidopsis / Q000235:genetics* / Q000378:metabolism / Q000382:microbiology; D029681:Arabidopsis Proteins / Q000235:genetics* / Q000378:metabolism; D018506:Gene Expression Regulation, Plant; D056892:Mediator Complex / Q000235:genetics / Q000378:metabolism*; D010935:Plant Diseases / Q000235:genetics* / Q000382:microbiology; D010937:Plant Growth Regulators / Q000235:genetics / Q000378:metabolism; D057865:Plant Immunity / Q000235:genetics*; D018515:Plant Leaves / Q000378:metabolism / Q000382:microbiology; D021122:Protein Subunits / Q000235:genetics / Q000378:metabolism; D044224:Pseudomonas syringae; D012319:RNA Polymerase II / Q000235:genetics / Q000378:metabolism; D015398:Signal Transduction; D014157:Transcription Factors / Q000235:genetics* / Q000378:metabolism
chemical_list: D029681:Arabidopsis Proteins; D056892:Mediator Complex; D010937:Plant Growth Regulators; D021122:Protein Subunits; D014157:Transcription Factors; D012319:RNA Polymerase II
keywords: Mediator; jasmonate/ethylene; plant defense; salicylate; transcription regulation