title: Natural variation in small molecule-induced TIR-NB-LRR signaling induces root growth arrest via EDS1- and PAD4-complexed R protein VICTR in Arabidopsis.
abstract: In a chemical genetics screen we identified the small-molecule [5-(3,4-dichlorophenyl)furan-2-yl]-piperidine-1-ylmethanethione (DFPM) that triggers rapid inhibition of early abscisic acid signal transduction via PHYTOALEXIN DEFICIENT4 (PAD4)- and ENHANCED DISEASE SUSCEPTIBILITY1 (EDS1)-dependent immune signaling mechanisms. However, mechanisms upstream of EDS1 and PAD4 in DFPM-mediated signaling remain unknown. Here, we report that DFPM generates an Arabidopsis thaliana accession-specific root growth arrest in Columbia-0 (Col-0) plants. The genetic locus responsible for this natural variant, VICTR (VARIATION IN COMPOUND TRIGGERED ROOT growth response), encodes a TIR-NB-LRR (for Toll-Interleukin1 Receptor-nucleotide binding-Leucine-rich repeat) protein. Analyses of T-DNA insertion victr alleles showed that VICTR is necessary for DFPM-induced root growth arrest and inhibition of abscisic acid-induced stomatal closing. Transgenic expression of the Col-0 VICTR allele in DFPM-insensitive Arabidopsis accessions recapitulated the DFPM-induced root growth arrest. EDS1 and PAD4, both central regulators of basal resistance and effector-triggered immunity, as well as HSP90 chaperones and their cochaperones RAR1 and SGT1B, are required for the DFPM-induced root growth arrest. Salicylic acid and jasmonic acid signaling pathway components are dispensable. We further demonstrate that VICTR associates with EDS1 and PAD4 in a nuclear protein complex. These findings show a previously unexplored association between a TIR-NB-LRR protein and PAD4 and identify functions of plant immune signaling components in the regulation of root meristematic zone-targeted growth arrest.
authors.affiliation: Division of Biological Sciences, Section of Cell and Developmental Biology, University of California at San Diego, La Jolla, California 92093-0116, USA.
authors.forename: Tae-Houn
authors.initials: TH
authors.lastname: Kim
authors.forename: Hans-Henning
authors.initials: HH
authors.lastname: Kunz
authors.forename: Saikat
authors.initials: S
authors.lastname: Bhattacharjee
authors.forename: Felix
authors.initials: F
authors.lastname: Hauser
authors.forename: Jiyoung
authors.initials: J
authors.lastname: Park
authors.forename: Cawas
authors.initials: C
authors.lastname: Engineer
authors.forename: Amy
authors.initials: A
authors.lastname: Liu
authors.forename: Tracy
authors.initials: T
authors.lastname: Ha
authors.forename: Jane E
authors.initials: JE
authors.lastname: Parker
authors.forename: Walter
authors.initials: W
authors.lastname: Gassmann
authors.forename: Julian I
authors.initials: JI
authors.lastname: Schroeder
mesh_terms: D017360:Arabidopsis / Q000235:genetics / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D002265:Carboxylic Ester Hydrolases / Q000235:genetics / Q000378:metabolism*; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D018517:Plant Roots / Q000235:genetics / Q000378:metabolism*; D015398:Signal Transduction / Q000235:genetics / Q000502:physiology*
chemical_list: D029681:Arabidopsis Proteins; D004268:DNA-Binding Proteins; C118837:EDS1 protein, Arabidopsis; D002265:Carboxylic Ester Hydrolases; C400766:PAD4 protein, Arabidopsis