title: Chemical genetics reveals negative regulation of abscisic acid signaling by a plant immune response pathway.
abstract: Coordinated regulation of protection mechanisms against environmental abiotic stress and pathogen attack is essential for plant adaptation and survival. Initial abiotic stress can interfere with disease-resistance signaling [1-6]. Conversely, initial plant immune signaling may interrupt subsequent abscisic acid (ABA) signal transduction [7, 8]. However, the processes involved in this crosstalk between these signaling networks have not been determined. By screening a 9600-compound chemical library, we identified a small molecule [5-(3,4-dichlorophenyl)furan-2-yl]-piperidine-1-ylmethanethione (DFPM) that rapidly downregulates ABA-dependent gene expression and also inhibits ABA-induced stomatal closure. Transcriptome analyses show that DFPM also stimulates expression of plant defense-related genes. Major early regulators of pathogen-resistance responses, including EDS1, PAD4, RAR1, and SGT1b, are required for DFPM-and notably also for Pseudomonas-interference with ABA signal transduction, whereas salicylic acid, EDS16, and NPR1 are not necessary. Although DFPM does not interfere with early ABA perception by PYR/RCAR receptors or ABA activation of SnRK2 kinases, it disrupts cytosolic Ca(2+) signaling and downstream anion channel activation in a PAD4-dependent manner. Our findings provide evidence that activation of EDS1/PAD4-dependent plant immune responses rapidly disrupts ABA signal transduction and that this occurs at the level of Ca(2+) signaling, illuminating how the initial biotic stress pathway interferes with ABA signaling.
authors.affiliation: Section of Cell and Developmental Biology, Division of Biological Sciences, University of California, San Diego, La Jolla, CA 92093-0116, USA.
authors.forename: Tae-Houn
authors.initials: TH
authors.lastname: Kim
authors.forename: Felix
authors.initials: F
authors.lastname: Hauser
authors.forename: Tracy
authors.initials: T
authors.lastname: Ha
authors.forename: Shaowu
authors.initials: S
authors.lastname: Xue
authors.forename: Maik
authors.initials: M
authors.lastname: Böhmer
authors.forename: Noriyuki
authors.initials: N
authors.lastname: Nishimura
authors.forename: Shintaro
authors.initials: S
authors.lastname: Munemasa
authors.forename: Katharine
authors.initials: K
authors.lastname: Hubbard
authors.forename: Nora
authors.initials: N
authors.lastname: Peine
authors.forename: Byeong-Ha
authors.initials: BH
authors.lastname: Lee
authors.forename: Stephen
authors.initials: S
authors.lastname: Lee
authors.forename: Nadia
authors.initials: N
authors.lastname: Robert
authors.forename: Jane E
authors.initials: JE
authors.lastname: Parker
authors.forename: Julian I
authors.initials: JI
authors.lastname: Schroeder
mesh_terms: D000040:Abscisic Acid / Q000378:metabolism / Q000494:pharmacology / Q000502:physiology*; D020869:Gene Expression Profiling; D018506:Gene Expression Regulation, Plant / Q000187:drug effects; D009997:Osmotic Pressure; D010880:Piperidines / Q000737:chemistry / Q000494:pharmacology; D010940:Plant Proteins / Q000235:genetics; D054046:Plant Stomata / Q000187:drug effects; D010944:Plants / Q000235:genetics* / Q000276:immunology / Q000378:metabolism / Q000382:microbiology; D044224:Pseudomonas syringae / Q000276:immunology; D015398:Signal Transduction; D054852:Small Molecule Libraries; D013312:Stress, Physiological; D013871:Thiones / Q000737:chemistry / Q000494:pharmacology
chemical_list: C561624:(5-(3,4-dichlorophenyl)furan-2-yl)piperidine-1-ylmethanethione; D010880:Piperidines; D010940:Plant Proteins; D054852:Small Molecule Libraries; D013871:Thiones; D000040:Abscisic Acid