Puncta‐localized TRAF domain protein TC1b contributes to the autoimmunity of snc1

Abstract

Immune receptors play important roles in the perception of pathogens and initiation of immune responses in both plants and animals. Intracellular nucleotide-binding domain leucine-rich repeat (NLR)-type receptors constitute a major class of receptors in vascular plants. In the Arabidopsis thaliana mutant suppressor of npr1-1, constitutive 1 (snc1), a gain-of-function mutation in the NLR gene SNC1 leads to SNC1 overaccumulation and constitutive activation of defense responses. From a CRISPR/Cas9-based reverse genetics screen in the snc1 autoimmune background, we identified that mutations in TRAF CANDIDATE 1b (TC1b), a gene encoding a protein with four tumor necrosis factor receptor-associated factor (TRAF) domains, can suppress snc1 phenotypes. TC1b does not appear to be a general immune regulator as it is not required for defense mediated by other tested immune receptors. TC1b also does not physically associate with SNC1, affect SNC1 accumulation, or affect signaling of the downstream helper NLRs represented by ACTIVATED DISEASE RESISTANCE PROTEIN 1-L2 (ADR1-L2), suggesting that TC1b impacts snc1 autoimmunity in a unique way. TC1b can form oligomers and localizes to punctate structures of unknown function. The puncta localization of TC1b strictly requires its coiledcoil (CC) domain, whereas the functionality of TC1b requires the four TRAF domains in addition to the CC. Overall, we uncovered the TRAF domain protein TC1b as a novel positive contributor to plant immunity.

Natural allelic variation confers diversity in the regulation of flag leaf traits in wheat

“…Immune receptors play important roles in the perception of pathogens and the initiation of immune responses in both plants and animals. A study by Ao et al 76 identified mutations in TRAF CANDIDATE 1b ( TC1b ), a gene encoding a protein with four tumor necrosis factor receptor-associated factor (TRAF) domains that were shown to suppress snc1 phenotypes underlying immune receptors. TC1b also does not physically associate with SNC1, affect SNC1 accumulation, or affect signaling of the downstream helper NLRs represented by ACTIVATED DISEASE RESISTANCE PROTEIN 1-L2 (ADR1-L2), suggesting that TC1b uniquely impacts snc1 autoimmunity.…”

Transcriptome analysis of resistant and susceptible M. truncatula genotypes in response to the necrotrophic fungus A. medicaginicola

“…Both calcium-binding protein MtPBP1 and peroxidase MtPrx28 are involved in ROS signaling and defense responses [35][36][37][38]. MATH domain-containing proteins have been shown to regulate NLR turnover in A. thaliana [39,40]. The top ten most upregulated DEGs in the resistant genotype occurred at 72 hpi, while the top ten downregulated DEGs occurred at all time points.…”