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1.
Curr Rheumatol Rep ; 23(11): 79, 2021 11 12.
Article in English | MEDLINE | ID: mdl-34767100

ABSTRACT

PURPOSE OF REVIEW: Three COVID-19 vaccines obtained emergency authorization from the Food and Drug Administration (FDA) and are widely used in the USA. Unfortunately, there is a paucity of evidence on the safety and efficacy of these vaccines in patients with autoimmune inflammatory rheumatic diseases (AIIRD), as these patients were excluded from all phases of vaccine development. Here we reviewed current data on COVID-19 vaccination in patients with AIIRD, with emphasis on systemic lupus erythematosus (SLE), and provided a comprehensive update on the benefits and risks of vaccination. RECENT FINDINGS: Patients with SLE have worse immune responses following SARS-CoV-2 vaccination than healthy controls. The efficacy of the COVID-19 vaccines seems to be further reduced by immunosuppressive medications, such as glucocorticoids (GC), methotrexate (MTX), mycophenolate/mycophenolic acid (MMF), and rituximab (RTX). However, these data do not substantiate that AIIRD patients are at greater risk of disease flares or have a higher incidence of side effects following vaccination. There is no significant safety concern for the use of COVID-19 vaccines in patients with AIIRD. The benefits of vaccination far outweigh the risks in patients with AIIRD, including SLE. More data are needed to determine the necessity of a booster vaccine dose and appropriate adjustment of immunosuppressants around the administration of vaccine.


Subject(s)
Autoimmune Diseases , COVID-19 , Lupus Erythematosus, Systemic , Rheumatic Diseases , Vaccines , COVID-19 Vaccines , Humans , SARS-CoV-2 , United States
4.
Plants (Basel) ; 9(9)2020 Aug 28.
Article in English | MEDLINE | ID: mdl-32872156

ABSTRACT

Maize (Zea mays L.) is a staple crop providing food security to millions of people in sub Saharan Africa. Fusarium verticillioides, an important fungal pathogen, infects maize causing 'Fusarium Ear Rot' disease, which decreases maize kernel yield and the quality of the crop harvested. Currently, no African maize line is completely resistant to infection by F. verticillioides. This study investigated an African maize line, Zea mays CML144, infected with F. verticillioides. Analysis of morphological characteristics showed significant differences between mock-infected and infected plants. RNA-sequencing (RNA-seq) was conducted on plants 14 days post-inoculation to identify differentially expressed genes (DEGs) involved in F. verticillioides infection. Analysis of RNA-seq data revealed DEGs that were both significantly up- and down-regulated in the infected samples compared to the mock-infected control. The maize TPS1 and cytochrome P450 genes were up-regulated, suggesting that kauralexins were involved in the CML144 defense response. This was substantiated by kauralexin analyses, which showed that kauralexins, belonging to class A and B, accumulated in infected maize tissue. Gene ontology terms relating to response to stimulus, chemical stimulus and carbohydrate metabolic processes were enriched, and the genes belonging to these GO-terms were down-regulated. Quantitative real-time PCR was performed on selected DEGs and measurement of phytoalexin accumulation validated the RNA-seq data and GO-analysis results. A comparison of DEGs from this study to DEGs found in F. verticillioides (ITEM 1744) infected susceptible (CO354) and resistant (CO441) maize genotypes in a previous study, matched 18 DEGs with 17 up-regulated and one down-regulated, respectively. This is the first transcriptomic study on the African maize line, CML144, in response to F. verticillioides infection.

5.
Elife ; 92020 01 15.
Article in English | MEDLINE | ID: mdl-31939738

ABSTRACT

For pathogens infecting single host species evolutionary trade-offs have previously been demonstrated between pathogen-induced mortality rates and transmission rates. It remains unclear, however, how such trade-offs impact sub-lethal pathogen-inflicted damage, and whether these trade-offs even occur in broad host-range pathogens. Here, we examine changes over the past 110 years in symptoms induced in maize by the broad host-range pathogen, maize streak virus (MSV). Specifically, we use the quantified symptom intensities of cloned MSV isolates in differentially resistant maize genotypes to phylogenetically infer ancestral symptom intensities and check for phylogenetic signal associated with these symptom intensities. We show that whereas symptoms reflecting harm to the host have remained constant or decreased, there has been an increase in how extensively MSV colonizes the cells upon which transmission vectors feed. This demonstrates an evolutionary trade-off between amounts of pathogen-inflicted harm and how effectively viruses position themselves within plants to enable onward transmission.


Subject(s)
Host-Pathogen Interactions/genetics , Maize streak virus , Plant Diseases/virology , Zea mays , Evolution, Molecular , Host-Pathogen Interactions/physiology , Maize streak virus/pathogenicity , Maize streak virus/physiology , Plant Diseases/classification , Plant Diseases/genetics , Plant Necrosis and Chlorosis/classification , Plant Necrosis and Chlorosis/genetics , Plant Necrosis and Chlorosis/virology , Zea mays/genetics , Zea mays/physiology , Zea mays/virology
6.
J Clin Rheumatol ; 26(5): 192-196, 2020 Aug.
Article in English | MEDLINE | ID: mdl-31022055

ABSTRACT

BACKGROUND/OBJECTIVE: Granulomatosis with polyangiitis (GPA) is a systemic necrotizing vasculitis that often results in frequent hospitalizations. We investigated the characteristics and predictors of 30-day hospital readmissions in GPA. METHODS: We performed a cross-sectional analysis using the 2014 National Readmission Database. We included nonelective admissions with a primary or secondary diagnosis of GPA. We compared characteristics between readmissions and nonreadmissions. Independent predictors for readmissions were studied using mixed-effects multivariable logistic regression. RESULTS: We evaluated a total of 9749 hospital admissions with GPA, among which there were 2173 readmissions (22.3%) within 30 days of discharge. The top 5 primary reasons for readmissions were GPA, sepsis, pneumonia, acute respiratory failure, and acute kidney injury. Granulomatosis with polyangiitis readmissions were associated with higher length of stay (8.0 vs 7.2 days; p = 0.019) and less discharge home (50% vs 63%, p < 0.001). Independent predictors for readmissions were younger age (odds ratio [OR], 0.99; p = 0.013), no private insurance (OR, 0.50; p < 0.001), higher Charlson Comorbidity Index (OR, 1.12; p = 0.039), congestive heart failure (OR, 1.71; p = 0.001), acute kidney injury (OR, 1.39; p = 0.005), and discharge to home health care (OR, 1.29; p = 0.039). CONCLUSIONS: We found a significant burden of 30-day readmissions among GPA populations. Clinicians should be vigilant regarding patients with high risk of readmissions, including those with younger age, public insurance, higher comorbidity burden, cardiac and renal complications, and unfavorable discharge dispositions.


Subject(s)
Granulomatosis with Polyangiitis , Patient Readmission , Cross-Sectional Studies , Databases, Factual , Granulomatosis with Polyangiitis/diagnosis , Granulomatosis with Polyangiitis/epidemiology , Granulomatosis with Polyangiitis/therapy , Hospitals , Humans , Retrospective Studies , Risk Factors , Time Factors , United States/epidemiology
7.
Int J Rheum Dis ; 22(6): 1023-1028, 2019 Jun.
Article in English | MEDLINE | ID: mdl-30834657

ABSTRACT

AIM: We investigated the association between systemic sclerosis (SSc) and perioperative cardiovascular risk for inpatient non-cardiac surgical procedures. METHODS: We used data from the National Inpatient Sample (NIS) for the year 2014 to identify patients undergoing inpatient non-cardiac surgery. SSc and major adverse cardiovascular events (MACE) were defined by International Classification of Diseases 9th Revision diagnosis codes. Univariate and multivariate analyses were performed. We adjusted for demographic information, socioeconomic status, cardiac comorbidities, cardiovascular risk factors and procedural category. Two models were used with different categorization strategies for surgical procedures. RESULTS: A total of 8 156 379 hospitalizations for non-cardiac surgeries were included, 4385 of which had a diagnosis of SSc. Patients with SSc were older, more likely to be female and Caucasian and with higher cardiac and systemic comorbidity burden. In univariate analysis, SSc was associated with higher risk of perioperative MACE (odds ratio [OR] = 2.9; P < 0.001) and all-cause death (P = 3.07; P < 0.001). Multivariate analysis yielded conflicting results regarding the association between SSc and perioperative MACE (Model 1: OR = 1.42; P = 0.146; Model 2: OR = 1.59; P = 0.048). Subsequent analysis showed that only perioperative myocardial infarction (Model 1 OR = 1.85; P = 0.048; Model 2 OR = 1.94; P = 0.031) was independently associated with SSc. CONCLUSION: We did not find consistent association between SSc and perioperative MACE in non-cardiac surgical procedures. SSc may be associated with perioperative myocardial infarction.


Subject(s)
Cardiovascular Diseases/epidemiology , Scleroderma, Systemic/epidemiology , Surgical Procedures, Operative/adverse effects , Cardiovascular Diseases/diagnosis , Cross-Sectional Studies , Databases, Factual , Female , Humans , Inpatients , Male , Middle Aged , Myocardial Infarction/epidemiology , Retrospective Studies , Risk Assessment , Risk Factors , Scleroderma, Systemic/diagnosis , Time Factors , Treatment Outcome , United States/epidemiology
8.
BMC Plant Biol ; 17(1): 197, 2017 Nov 13.
Article in English | MEDLINE | ID: mdl-29132306

ABSTRACT

BACKGROUND: Cercospora zeina is a foliar pathogen responsible for maize grey leaf spot in southern Africa that negatively impacts maize production. Plants use a variety of chemical and structural mechanisms to defend themselves against invading pathogens such as C. zeina, including the production of secondary metabolites with antimicrobial properties. In maize, a variety of biotic and abiotic stressors induce the accumulation of the terpenoid phytoalexins, zealexins and kauralexins. RESULTS: C. zeina-susceptible line displayed pervasive rectangular grey leaf spot lesions, running parallel with the leaf veins in contrast to C. zeina-resistant line that had restricted disease symptoms. Analysis of the transcriptome of both lines indicated that genes involved in primary and secondary metabolism were up-regualted, and although different pathways were prioritized in each line, production of terpenoid compounds were common to both. Targeted phytoalexin analysis revealed that C. zeina-inoculated leaves accumulated zealexins and kauralexins. The resistant line shows a propensity toward accumulation of the kauralexin B series metabolites in response to infection, which contrasts with the susceptible line that preferentially accumulates the kauralexin A series. Kauralexin accumulation was correlated to expression of the kauralexin biosynthetic gene, ZmAn2 and a candidate biosynthetic gene, ZmKSL2. We report the expression of a putative copalyl diphosphate synthase gene that is induced by C. zeina in the resistant line exclusively. DISCUSSION: This study shows that zealexins and kauralexins, and expression of their biosynthetic genes, are induced by C. zeina in both resistant and susceptible germplasm adapted to the southern African climate. The data presented here indicates that different forms of kauralexins accumulate in the resistant and susceptible maize lines in response to C. zeina, with the accumulation of kauralexin B compounds in a resistant maize line and kauralexin A compounds accumulating in the susceptible line.


Subject(s)
Ascomycota/pathogenicity , Disease Resistance/genetics , Plant Diseases/genetics , Terpenes/metabolism , Zea mays/genetics , Gene Ontology , Plant Diseases/microbiology , Plant Leaves/microbiology , Sequence Analysis, RNA , Zea mays/metabolism , Zea mays/microbiology
9.
PLoS One ; 12(8): e0182629, 2017.
Article in English | MEDLINE | ID: mdl-28813447

ABSTRACT

Phytoplasmas are cell wall-less plant pathogenic bacteria responsible for major crop losses throughout the world. In grapevine they cause grapevine yellows, a detrimental disease associated with a variety of symptoms. The high economic impact of this disease has sparked considerable interest among researchers to understand molecular mechanisms related to pathogenesis. Increasing evidence exist that a class of small non-coding endogenous RNAs, known as microRNAs (miRNAs), play an important role in post-transcriptional gene regulation during plant development and responses to biotic and abiotic stresses. Thus, we aimed to dissect complex high-throughput small RNA sequencing data for the genome-wide identification of known and novel differentially expressed miRNAs, using read libraries constructed from healthy and phytoplasma-infected Chardonnay leaf material. Furthermore, we utilised computational resources to predict putative miRNA targets to explore the involvement of possible pathogen response pathways. We identified multiple known miRNA sequence variants (isomiRs), likely generated through post-transcriptional modifications. Sequences of 13 known, canonical miRNAs were shown to be differentially expressed. A total of 175 novel miRNA precursor sequences, each derived from a unique genomic location, were predicted, of which 23 were differentially expressed. A homology search revealed that some of these novel miRNAs shared high sequence similarity with conserved miRNAs from other plant species, as well as known grapevine miRNAs. The relative expression of randomly selected known and novel miRNAs was determined with real-time RT-qPCR analysis, thereby validating the trend of expression seen in the normalised small RNA sequencing read count data. Among the putative miRNA targets, we identified genes involved in plant morphology, hormone signalling, nutrient homeostasis, as well as plant stress. Our results may assist in understanding the role that miRNA pathways play during plant pathogenesis, and may be crucial in understanding disease symptom development in aster yellows phytoplasma-infected grapevines.


Subject(s)
Gene Expression Regulation, Plant , High-Throughput Nucleotide Sequencing , MicroRNAs/genetics , Phytoplasma , Plant Diseases/genetics , Plant Diseases/microbiology , Vitis/genetics , Vitis/microbiology , Base Sequence , Computational Biology/methods , Gene Expression Profiling , Indoleacetic Acids/metabolism , Molecular Sequence Annotation , Nucleic Acid Conformation , RNA Interference , RNA, Messenger/genetics , Reproducibility of Results , Signal Transduction
10.
Plant J ; 89(4): 746-763, 2017 Feb.
Article in English | MEDLINE | ID: mdl-27862526

ABSTRACT

We used a systems genetics approach to elucidate the molecular mechanisms of the responses of maize to grey leaf spot (GLS) disease caused by Cercospora zeina, a threat to maize production globally. Expression analysis of earleaf samples in a subtropical maize recombinant inbred line population (CML444 × SC Malawi) subjected in the field to C. zeina infection allowed detection of 20 206 expression quantitative trait loci (eQTLs). Four trans-eQTL hotspots coincided with GLS disease QTLs mapped in the same field experiment. Co-expression network analysis identified three expression modules correlated with GLS disease scores. The module (GY-s) most highly correlated with susceptibility (r = 0.71; 179 genes) was enriched for the glyoxylate pathway, lipid metabolism, diterpenoid biosynthesis and responses to pathogen molecules such as chitin. The GY-s module was enriched for genes with trans-eQTLs in hotspots on chromosomes 9 and 10, which also coincided with phenotypic QTLs for susceptibility to GLS. This transcriptional network has significant overlap with the GLS susceptibility response of maize line B73, and may reflect pathogen manipulation for nutrient acquisition and/or unsuccessful defence responses, such as kauralexin production by the diterpenoid biosynthesis pathway. The co-expression module that correlated best with resistance (TQ-r; 1498 genes) was enriched for genes with trans-eQTLs in hotspots coinciding with GLS resistance QTLs on chromosome 9. Jasmonate responses were implicated in resistance to GLS through co-expression of COI1 and enrichment of genes with the Gene Ontology term 'cullin-RING ubiquitin ligase complex' in the TQ-r module. Consistent with this, JAZ repressor expression was highly correlated with the severity of GLS disease in the GY-s susceptibility network.


Subject(s)
Plant Leaves/genetics , Plant Leaves/microbiology , Zea mays/genetics , Zea mays/microbiology , Ascomycota/pathogenicity , Chromosomes, Plant/genetics , Gene Regulatory Networks/genetics , Gene Regulatory Networks/physiology , Plant Diseases/genetics , Plant Diseases/microbiology , Quantitative Trait Loci/genetics
11.
PLoS One ; 9(10): e109853, 2014.
Article in English | MEDLINE | ID: mdl-25303634

ABSTRACT

The Arabidopsis constitutive induced resistance 1 (cir1) mutant displays salicylic acid (SA)-dependent constitutive expression of defence genes and enhanced resistance to biotrophic pathogens. To further characterise the role of CIR1 in plant immunity we conducted epistasis analyses with two key components of the SA-signalling branch of the defence network, ENHANCED DISEASE SUSCEPTIBILITY1 (EDS1) and PHYTOALEXIN DEFICIENT4 (PAD4). We demonstrate that the constitutive defence phenotypes of cir1 require both EDS1 and PAD4, indicating that CIR1 lies upstream of the EDS1-PAD4 regulatory node in the immune signalling network. In light of this finding we examined EDS1 expression in cir1 and observed increased protein, but not mRNA levels in this mutant, suggesting that CIR1 might act as a negative regulator of EDS1 via a post-transcriptional mechanism. Finally, as environmental temperature is known to influence the outcome of plant-pathogen interactions, we analysed cir1 plants grown at 18, 22 or 25°C. We found that susceptibility to Pseudomonas syringae pv. tomato (Pst) DC3000 is modulated by temperature in cir1. Greatest resistance to this pathogen (relative to PR-1:LUC control plants) was observed at 18°C, while at 25°C no difference in susceptibility between cir1 and control plants was apparent. The increase in resistance to Pst DC3000 at 18°C correlated with a stunted growth phenotype, suggesting that activation of defence responses may be enhanced at lower temperatures in the cir1 mutant.


Subject(s)
Arabidopsis Proteins/genetics , Arabidopsis/genetics , Carboxylic Ester Hydrolases/genetics , DNA-Binding Proteins/genetics , Plants, Genetically Modified/genetics , Temperature , Arabidopsis/metabolism , Arabidopsis Proteins/metabolism , Carboxylic Ester Hydrolases/metabolism , DNA-Binding Proteins/metabolism , Gene Expression Regulation, Plant , Host-Pathogen Interactions , Plant Diseases/genetics , Plants, Genetically Modified/metabolism , Signal Transduction/genetics
12.
BMC Plant Biol ; 8: 24, 2008 Feb 29.
Article in English | MEDLINE | ID: mdl-18307823

ABSTRACT

BACKGROUND: Plant natriuretic peptides (PNPs) are a class of systemically mobile molecules distantly related to expansins. While several physiological responses to PNPs have been reported, their biological role has remained elusive. Here we use a combination of expression correlation analysis, meta-analysis of gene expression profiles in response to specific stimuli and in selected mutants, and promoter content analysis to infer the biological role of the Arabidopsis thaliana PNP, AtPNP-A. RESULTS: A gene ontology analysis of AtPNP-A and the 25 most expression correlated genes revealed a significant over representation of genes annotated as part of the systemic acquired resistance (SAR) pathway. Transcription of these genes is strongly induced in response to salicylic acid (SA) and its functional synthetic analogue benzothiadiazole S-methylester (BTH), a number of biotic and abiotic stresses including many SA-mediated SAR-inducing conditions, as well as in the constitutive SAR expressing mutants cpr5 and mpk4 which have elevated SA levels. Furthermore, the expression of AtPNP-A was determined to be significantly correlated with the SAR annotated transcription factor, WRKY 70, and the promoters of AtPNP-A and the correlated genes contain an enrichment in the core WRKY binding W-box cis-elements. In constitutively expressing WRKY 70 lines the expression of AtPNP-A and the correlated genes, including the SAR marker genes, PR-2 and PR-5, were determined to be strongly induced. CONCLUSION: The co-expression analyses, both in wild type and mutants, provides compelling evidence that suggests AtPNP-A may function as a component of plant defence responses and SAR in particular. The presented evidence also suggests that the expression of AtPNP-A is controlled by WRKY transcription factors and WRKY 70 in particular. AtPNP-A shares many characteristics with PR proteins in that its transcription is strongly induced in response to pathogen challenges, it contains an N-terminal signalling peptide and is secreted into the extracellular space and along with PR-1, PR-2 and PR-5 proteins it has been isolated from the Arabidopsis apoplast. Based on these findings we suggest that AtPNP-A could be classified as a newly identified PR protein.


Subject(s)
Arabidopsis Proteins/metabolism , Arabidopsis/genetics , Gene Expression Regulation, Plant , Promoter Regions, Genetic/genetics , Arabidopsis Proteins/genetics , Gene Expression Profiling , Natriuretic Peptides/genetics , Natriuretic Peptides/metabolism , Protein Array Analysis , Regulatory Elements, Transcriptional , Transcription Factors
13.
Mol Plant Microbe Interact ; 20(11): 1431-8, 2007 Nov.
Article in English | MEDLINE | ID: mdl-17977154

ABSTRACT

Basal resistance is the ultimately unsuccessful plant defense response to infection with a virulent pathogen. It is thought to be triggered by host recognition of pathogen-associated molecular patterns, with subsequent suppression of particular components by pathogen effectors. To identify novel components of Arabidopsis basal resistance against the bacterial pathogen Pseudomonas syringae pv. tomato, microarray expression profiling was carried out on the cirl mutant, which displays enhanced resistance against P. syringae pv. tomato. This identified two genes, At4g23810 and At2g40000, encoding the transcription factor WRKY53 and the nematode resistance protein-like HSPRO2, whose expression was upregulated in cir1 prior to pathogen infection and in wild-type plants after P. syringae pv. tomato infection. WRKY53 and HSPRO2 are positive regulators of basal resistance. Knockout mutants of both genes were more susceptible to P. syringae pv. tomato infection than complemented lines, with increased growth of the pathogen in planta. WRKY53 and HSPRO2 appear to function downstream of salicylic acid and to be negatively regulated by signaling through jasmonic acid and ethylene.


Subject(s)
Arabidopsis Proteins/genetics , Arabidopsis/genetics , Arabidopsis/microbiology , DNA-Binding Proteins/genetics , Plant Diseases/genetics , Pseudomonas syringae , Animals , Arabidopsis/metabolism , Arabidopsis Proteins/metabolism , DNA-Binding Proteins/metabolism , Gene Expression Profiling , Gene Expression Regulation, Plant , Genetic Predisposition to Disease , Molecular Sequence Data , Mutation , Nematoda , Plant Diseases/parasitology , Protein Array Analysis
14.
Plant J ; 41(5): 673-84, 2005 Mar.
Article in English | MEDLINE | ID: mdl-15703055

ABSTRACT

We report the characterization of an Arabidopsis thaliana mutant, ups1, isolated on the basis of reduced expression of phosphoribosylanthranilate transferase, a tryptophan biosynthetic enzyme. ups1 also exhibits defects in a wide range of defence responses. After infection with Pseudomonas syringae or Botrytis cinerea, the expression of genes regulated by both the salicylic acid and jasmonic acid/ethylene pathways is reduced in ups1 compared with wild type. Camalexin accumulation in ups1 is greatly reduced after infection with these two pathogens, as well as after amino acid starvation or oxidative stress. Reactive oxygen species (ROS)-mediated gene expression is also compromised in ups1 indicating that this mutant is defective in signalling pathways activated in response to both biotic and abiotic stress. The fact that all three major defence signalling pathways are disrupted in ups1, together with the oxidative stress phenotype, leads us to suggest that UPS1 is involved in ROS signal transduction.


Subject(s)
Arabidopsis Proteins/genetics , Arabidopsis/physiology , Membrane Transport Proteins/genetics , Mutation , Signal Transduction/physiology , Arabidopsis/genetics , Arabidopsis/microbiology , Botrytis/pathogenicity , Indoles/metabolism , Plant Diseases/microbiology , Pseudomonas syringae/pathogenicity , Thiazoles/metabolism
15.
Mol Plant Pathol ; 6(1): 31-41, 2005 Jan 01.
Article in English | MEDLINE | ID: mdl-20565636

ABSTRACT

SUMMARY A complex signal transduction network involving salicylic acid, jasmonic acid and ethylene underlies disease resistance in Arabidopsis. To understand this defence signalling network further, we identified mutants that expressed the marker gene PR-1::luciferase in the absence of pathogen infection. These cir mutants all display constitutive expression of a suite of defence-related genes but exhibit different disease resistance profiles to two biotrophic pathogens, Pseudomonas syringae pv. tomato and Peronospora parasitica NOCO2, and the necrotrophic pathogen Botrytis cinerea. We further characterized cir3, which displays enhanced resistance only to the necrotrophic pathogen. Cir3-mediated resistance to B. cinerea is dependent on accumulated salicylic acid and a functional EIN2 protein.

16.
Mol Plant Microbe Interact ; 15(6): 557-66, 2002 Jun.
Article in English | MEDLINE | ID: mdl-12059104

ABSTRACT

In order to identify components of the defense signaling network engaged following attempted pathogen invasion, we generated a novel PR-1::luciferase (LUC) transgenic line that was deployed in an imaging-based screen to uncover defense-related mutants. The recessive mutant designated cir1 exhibited constitutive expression of salicylic acid (SA), jasmonic acid (JA)/ethylene, and reactive oxygen intermediate-dependent genes. Moreover, this mutation conferred resistance against the bacterial pathogen Pseudomonas syringae pv. tomato DC3000 and a virulent oomycete pathogen Peronospora parasitica Noco2. Epistasis analyses were undertaken between cir1 and mutants that disrupt the SA (nprl, nahG), JA (jar1), and ethylene (ET) (ein2) signaling pathways. While resistance against both P. syringae pv. tomato DC3000 and Peronospora parasitica Noco2 was partially reduced by npr1, resistance against both of these pathogens was lost in an nahG genetic background. Hence, cirl-mediated resistance is established via NPR1-dependent and -independent signaling pathways and SA accumulation is essential for the function of both pathways. While jar1 and ein2 reduced resistance against P. syringae pv. tomato DC3000, these mutations appeared not to impact cir1-mediated resistance against Peronospora parasitica Noco2. Thus, JA and ET sensitivity are required for cir1-mediated resistance against P. syringae pv. tomato DC3000 but not Peronospora parasitica Noco2. Therefore, the cir1 mutation may define a negative regulator of disease resistance that operates upstream of SA, JA, and ET accumulation.


Subject(s)
Arabidopsis/genetics , Mutation/genetics , Plant Diseases/genetics , Arabidopsis/growth & development , Arabidopsis/microbiology , Arabidopsis Proteins/genetics , Arabidopsis Proteins/metabolism , Cyclopentanes/metabolism , Epistasis, Genetic , Ethylenes/metabolism , Gene Expression Regulation, Developmental , Gene Expression Regulation, Plant , Immunity, Innate/genetics , Luciferases/genetics , Luciferases/metabolism , Mixed Function Oxygenases/genetics , Mixed Function Oxygenases/metabolism , Nucleotidyltransferases/genetics , Nucleotidyltransferases/metabolism , Oomycetes/pathogenicity , Oxylipins , Plant Diseases/microbiology , Plant Proteins/genetics , Plant Proteins/metabolism , Plants, Genetically Modified , Pseudomonas/pathogenicity , Reactive Oxygen Species/metabolism , Receptors, Cell Surface/genetics , Receptors, Cell Surface/metabolism , Salicylic Acid/metabolism , Virulence
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