The Arabidopsis NSL2 negatively controls systemic acquired resistance via hypersensitive response

Asada, Yutaka; Yamamoto, Masahide; Tsutsui, Tomokazu; Yamaguchi, Junji

doi:10.5511/plantbiotechnology.10.0913a

“…Similar to what has been reported for cad1 null alleles (Morita-Yamamuro et al 2005;Asada et al 2011), we found that cad1-5 plants displayed heightened basal expression of the immune marker gene PR1 (Figure 2B), which was complemented in the two cad1-5/pCAD1:gCAD1 lines. We next assessed pattern-triggered immune responses and found that cad1-5 displayed enhanced elf18-and AtPep1-triggered ROS production (Figures 2C, S4A) and seedling growth inhibition (Figure 2D, S4B), which were again fully complemented in the cad1-5/pCAD1:gCAD1 lines.…”

Section: Reduced Cad1 Accumulation Correlates With Enhanced Immune Sisupporting

confidence: 88%

A novel allele in theArabidopsis thalianaMACPF protein CAD1 results in deregulated immune signaling

Holmes

¹

,

Bredow

²

,

Thor

³

et al. 2021

Preprint

0

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Immune recognition in plants is governed by two major classes of receptors: pattern recognition receptors (PRRs) and nucleotide-binding leucine-rich repeat receptors (NLRs). Located at the cell surface, PRRs bind extracellular ligands originating from microbes (indicative of ‘non-self’) or damaged plant cells (indicative of ‘infected-self’), and trigger signaling cascades to protect against infection. Located intracellularly, NLRs sense pathogen-induced physiological changes and trigger localized cell death and systemic resistance. Immune responses are under tight regulation in order to maintain homeostasis and promote plant health. In a forward-genetic screen to identify regulators of PRR-mediated immune signaling, we identified a novel allele of the membrane-attack complex and perforin (MACPF)-motif containing protein CONSTITUTIVE ACTIVE DEFENSE 1 (CAD1) resulting from a missense mutation in a conserved N-terminal cysteine. We show that cad1-5 mutants display deregulated immune signaling and symptoms of autoimmunity dependent on the lipase-like protein ENHANCED DISEASE SUSCEPTIBILITY1 (EDS1), suggesting that CAD1 integrity is monitored by the plant immune system. We further demonstrate that CAD1 localizes to both the cytosol and plasma membrane using confocal microscopy and subcellular fractionation. Our results offer new insights into immune homeostasis and provide tools to further decipher the intriguing role of MACPF proteins in plants.

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“…In our study, the mildew resistance locus 12 gene ( MLO12 ) had one associated transcript with complete downregulation in all treatments ( Figure 5C ), and a second transcript slightly upregulated at 7 dai in both genotypes ( Supplementary Figure S3A ), while a transcript matching MLO2 showed a trend similar to the second MLO12 transcript. Another gene, CAD1 (constitutively activated cell death 1) negatively regulates SA-mediated responses, with knockouts of the gene resulting in activation of PR1 ( Asada et al., 2011 ). Downregulation of this gene in our study, mainly in the case of ‘Laurentian' ( Figure 5C and Supplementary Figure S3C ), supports steady SA-mediated immunity.…”

Section: Resultsmentioning

confidence: 99%

Response of Brassica napus to Plasmodiophora brassicae Involves Salicylic Acid-Mediated Immunity: An RNA-Seq-Based Study

Galindo‐González

¹

,

Manolii

²

,

Hwang

³

et al. 2020

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Clubroot, caused by the obligate parasite Plasmodiophora brassicae , is an important disease of the Brassicaceae and poses a significant threat to the $26.7 billion canola/oilseed rape ( Brassica napus ) industry in western Canada. While clubroot is managed most effectively by planting resistant host varieties, new pathotypes of P. brassicae have emerged recently that can overcome this resistance. Whole genome analyses provide both a toolbox and a systemic view of molecular mechanisms in host-pathogen interactions, which can be used to design new breeding strategies to increase P. brassicae resistance. We used RNA-seq to evaluate differential gene expression at 7, 14 and 21 days after inoculation (dai) of two B. napus genotypes with differential responses to P. brassicae pathotype 5X. Gall development was evident at 14 dai in the susceptible genotype (the oilseed rape ‘Brutor’), while gall development in the resistant genotype (the rutabaga ( B. napus ) ‘Laurentian’) was limited and not visible until 21 dai. Immune responses were better sustained through the time-course in ‘Laurentian’, and numerous genes from immune-related functional categories were associated with salicylic acid (SA)-mediated responses. Jasmonic acid (JA)-mediated responses seemed to be mostly inhibited, especially in the resistant genotype. The upregulation of standard defense-related proteins, like chitinases and thaumatins, was evident in ‘Laurentian’. The enrichment, in both host genotypes, of functional categories for syncytium formation and response to nematodes indicated that cell enlargement during P. brassicae infection, and the metabolic processes therein, share similarities with the response to infection by nematodes that produce similar anatomical symptoms. An analysis of shared genes between the two genotypes at different time-points, confirmed that the nematode-like responses occurred earlier for ‘Brutor’, along with cell metabolism and growth changes. Additionally, the susceptible cultivar turned off defense mechanisms earlier than ‘Laurentian’. Collectively, this study showed the importance of SA in triggering immune responses and suggested some key resistance and susceptibility factors that can be used in future studies for resistance breeding through gene-editing approaches.

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“…There are four MACPF-motif containing proteins encoded in the model plant Arabidopsis thaliana. Although two of these, CONSTITUTIVE ACTIVE DEFENSE 1 (CAD1) and NECROTIC SPOTTED LESIONS 1 (NSL1), have been studied genetically (Morita-Yamamuro et al 2005;Noutoshi et al 2006;Tsutsui et al 2006;Asada et al 2011;Fukunaga et al 2017;Chen et al 2020), the molecular function of Arabidopsis MACPF proteins remains elusive. In this study, we isolated a novel allele of CAD1 from a forward-genetics screen (Monaghan et al, 2014) designed to identify loci important for immune homeostasis.…”

Section: Introductionmentioning

confidence: 99%

A novel allele of the Arabidopsis thaliana MACPF protein CAD1 results in deregulated immune signaling

Holmes

¹

,

Bredow

²

,

Thor

³

et al. 2021

View full text Add to dashboard Cite

Immune recognition in plants is governed by two major classes of receptors: pattern recognition receptors (PRRs) and nucleotide-binding leucine-rich repeat receptors (NLRs). Located at the cell surface, PRRs bind extracellular ligands originating from microbes (indicative of ‘non-self’) or damaged plant cells (indicative of ‘infected-self’), and trigger signaling cascades to protect against infection. Located intracellularly, NLRs sense pathogen-induced physiological changes and trigger localized cell death and systemic resistance. Immune responses are under tight regulation in order to maintain homeostasis and promote plant health. In a forward-genetic screen to identify regulators of PRR-mediated immune signaling, we identified a novel allele of the membrane-attack complex and perforin (MACPF)-motif containing protein CONSTITUTIVE ACTIVE DEFENSE 1 (CAD1) resulting from a missense mutation in a conserved N-terminal cysteine. We show that cad1-5 mutants display deregulated immune signaling and symptoms of autoimmunity dependent on the lipase-like protein ENHANCED DISEASE SUSCEPTIBILITY1 (EDS1), suggesting that CAD1 integrity is monitored by the plant immune system. We further demonstrate that CAD1 localizes to both the cytosol and plasma membrane using confocal microscopy and subcellular fractionation. Our results offer new insights into immune homeostasis and provide tools to further decipher the intriguing role of MACPF proteins in plants.

show abstract

The Arabidopsis NSL2 negatively controls systemic acquired resistance via hypersensitive response

Cited by 13 publications

References 34 publications

A novel allele in theArabidopsis thalianaMACPF protein CAD1 results in deregulated immune signaling

A novel allele in theArabidopsis thalianaMACPF protein CAD1 results in deregulated immune signaling

Response of Brassica napus to Plasmodiophora brassicae Involves Salicylic Acid-Mediated Immunity: An RNA-Seq-Based Study

A novel allele of the Arabidopsis thaliana MACPF protein CAD1 results in deregulated immune signaling

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