Autoimmunity conferred by chs3-2D relies on CSA1, its adjacent TNL-encoding neighbour.
Plant innate immunity depends on the function of a large number of intracellular immune receptor proteins, the majority of which are structurally similar to mammalian nucleotide-binding oligomerization domain (NOD)-like receptor (NLR) proteins. CHILLING SENSITIVE 3 (CHS3) encodes an atypical Toll/Interleukin 1 Receptor (TIR)-type NLR protein with an additional Lin-11, Isl-1 and Mec-3 (LIM) domain at its C-terminus. The gain-of-function mutant allele chs3-2D exhibits severe dwarfism and constitutively activated defense responses, including enhanced resistance to virulent pathogens, high defence marker gene expression, and salicylic acid accumulation. To search for novel regulators involved in CHS3-mediated immune signaling, we conducted suppressor screens in the chs3-2D and chs3-2D pad4-1 genetic backgrounds. Alleles of sag101 and eds1-90 were isolated as complete suppressors of chs3-2D, and alleles of sgt1b were isolated as partial suppressors of chs3-2D pad4-1. These mutants suggest that SAG101, EDS1-90, and SGT1b are all positive regulators of CHS3-mediated defense signaling. Additionally, the TIR-type NLR-encoding CSA1 locus located genomically adjacent to CHS3 was found to be fully required for chs3-2D-mediated autoimmunity. CSA1 is located 3.9 kb upstream of CHS3 and is transcribed in the opposite direction. Altogether, these data illustrate the distinct genetic requirements for CHS3-mediated defense signaling.
1] Michael Smith Laboratories, University of British Columbia, Vancouver, BC V6T 1Z4, Canada [2] Department of Botany, University of British Columbia, Vancouver, BC V6T 1Z4, Canada.
Fang
F
Xu
1] Michael Smith Laboratories, University of British Columbia, Vancouver, BC V6T 1Z4, Canada [2] Department of Botany, University of British Columbia, Vancouver, BC V6T 1Z4, Canada.
Chipan
C
Zhu
1] University of Warwick, School of Life Sciences, Warwick Crop Centre, Wellesbourne, CV35 9EF, United Kingdom [2] Sainsbury Laboratory, Norwich Research Park, Colney Lane, Norwich, NR4 7UH, United Kingdom.
Volkan
V
Cevik
1] Michael Smith Laboratories, University of British Columbia, Vancouver, BC V6T 1Z4, Canada [2] Department of Botany, University of British Columbia, Vancouver, BC V6T 1Z4, Canada.
Kaeli
K
Johnson
Department of Botany, University of British Columbia, Vancouver, BC V6T 1Z4, Canada.
Yanan
Y
Liu
1] Sainsbury Laboratory, Norwich Research Park, Colney Lane, Norwich, NR4 7UH, United Kingdom [2] Bio-protection Research Centre, Institute of Agriculture and Environment, Massey University, Private Bag 11222, Palmerston North. 4442, New Zealand.
Kee
K
Sohn
Sainsbury Laboratory, Norwich Research Park, Colney Lane, Norwich, NR4 7UH, United Kingdom.
Jonathan D
JD
Jones
University of Warwick, School of Life Sciences, Warwick Crop Centre, Wellesbourne, CV35 9EF, United Kingdom.
Eric B
EB
Holub
1] Michael Smith Laboratories, University of British Columbia, Vancouver, BC V6T 1Z4, Canada [2] Department of Botany, University of British Columbia, Vancouver, BC V6T 1Z4, Canada.
Xin
X
Li
D015551:Autoimmunity / Q000235:genetics*; D018506:Gene Expression Regulation, Plant; D005816:Genetic Complementation Test; D056426:Genetic Loci; D009154:Mutation; D010641:Phenotype; D010940:Plant Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D010944:Plants / Q000235:genetics* / Q000276:immunology* / Q000378:metabolism; D011995:Recombination, Genetic; D015398:Signal Transduction
D010940:Plant Proteins