Opposing functions of the plant TOPLESS gene family during SNC1-mediated autoimmunity

Autor: Benjamin J. Spears, Samantha N. Smith, Christopher M. Garner, Walter Gassmann, Leland J. Cseke, Jianbin Su, Conner J. Rogan
Rok vydání: 2020
Předmět:
0106 biological sciences
Cancer Research
Mutant
Arabidopsis
Gene Expression
Autoimmunity
QH426-470
medicine.disease_cause
01 natural sciences
Gene Expression Regulation
Plant
Transcriptional regulation
Medicine and Health Sciences
Arabidopsis thaliana
Plant Immunity
Genetics (clinical)
Genetics
Regulation of gene expression
0303 health sciences
Mutation
Transcriptional Control
Eukaryota
Plants
Plants
Genetically Modified
Phenotype
Up-Regulation
Phenotypes
Experimental Organism Systems
Research Article
Arabidopsis Thaliana
Immunology
Brassica
Biology
Research and Analysis Methods
03 medical and health sciences
Immune system
Model Organisms
Immunity
Gene Types
Plant and Algal Models
medicine
Gene family
Gene Regulation
Molecular Biology
Ecology
Evolution
Behavior and Systematics
030304 developmental biology
Arabidopsis Proteins
Organisms
Biology and Life Sciences
biology.organism_classification
Immune System
Animal Studies
Regulator Genes
010606 plant biology & botany
Molecular Chaperones
Zdroj: PLoS Genetics
PLoS Genetics, Vol 17, Iss 2, p e1009026 (2021)
ISSN: 1553-7404
Popis: Regulation of the plant immune system is important for controlling the specificity and amplitude of responses to pathogens and in preventing growth-inhibiting autoimmunity that leads to reductions in plant fitness. In previous work, we reported that SRFR1, a negative regulator of effector-triggered immunity, interacts with SNC1 and EDS1. When SRFR1 is non-functional in the Arabidopsis accession Col-0, SNC1 levels increase, causing a cascade of events that lead to autoimmunity phenotypes. Previous work showed that some members of the transcriptional co-repressor family TOPLESS interact with SNC1 to repress negative regulators of immunity. Therefore, to explore potential connections between SRFR1 and TOPLESS family members, we took a genetic approach that examined the effect of each TOPLESS member in the srfr1 mutant background. The data indicated that an additive genetic interaction exists between SRFR1 and two members of the TOPLESS family, TPR2 and TPR3, as demonstrated by increased stunting and elevated PR2 expression in srfr1 tpr2 and srfr1 tpr2 tpr3 mutants. Furthermore, the tpr2 mutation intensifies autoimmunity in the auto-active snc1-1 mutant, indicating a novel role of these TOPLESS family members in negatively regulating SNC1-dependent phenotypes. This negative regulation can also be reversed by overexpressing TPR2 in the srfr1 tpr2 background. Similar to TPR1 that positively regulates snc1-1 phenotypes by interacting with SNC1, we show here that TPR2 directly binds the N-terminal domain of SNC1. In addition, TPR2 interacts with TPR1 in vivo, suggesting that the opposite functions of TPR2 and TPR1 are based on titration of SNC1-TPR1 complexes by TPR2 or altered functions of a SNC1-TPR1-TPR2 complex. Thus, this work uncovers diverse functions of individual members of the TOPLESS family in Arabidopsis and provides evidence for the additive effect of transcriptional and post-transcriptional regulation of SNC1.
Author summary The immune system is a double-edged sword that affords organisms with protection against infectious diseases but can also lead to negative effects if not properly controlled. Plants only possess an innate antimicrobial immune system that relies on rapid upregulation of defenses once immune receptors detect the presence of microbes. Plant immune receptors known as resistance proteins play a key role in rapidly triggering defenses if pathogens breach other defenses. A common model of unregulated immunity in the reference Arabidopsis variety Columbia-0 involves a resistance gene called SNC1. When the SNC1 protein accumulates to unnaturally high levels or possesses auto-activating mutations, the visible manifestations of immune overactivity include stunted growth and low biomass and seedset. Consequently, expression of this gene and accumulation of the encoded protein are tightly regulated on multiple levels. Despite careful study the mechanisms of SNC1 gene regulation are not fully understood. Here we present data on members of the well-known TOPLESS family of transcriptional repressors. While previously characterized members were shown to function in indirect activation of defenses, TPR2 and TPR3 are shown here to function in preventing high defense activity. This study therefore contributes to the understanding of complex regulatory processes in plant immunity.
Databáze: OpenAIRE
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