scholarly journals The Arabidopsis ATAF1, a NAC Transcription Factor, Is a Negative Regulator of Defense Responses Against Necrotrophic Fungal and Bacterial Pathogens

2009 ◽  
Vol 22 (10) ◽  
pp. 1227-1238 ◽  
Author(s):  
Xiao'e Wang ◽  
B. M. Vindhya S. Basnayake ◽  
Huijuan Zhang ◽  
Guojun Li ◽  
Wei Li ◽  
...  
Keyword(s):  
Pseudomonas Syringae ◽  
Bacterial Pathogens ◽  
Defense Responses ◽  
Ethylene Biosynthesis ◽  
Negative Regulator ◽  
Alternaria Brassicicola ◽  
Tomato Dc3000 ◽  
Pathogenesis Related ◽  
Direct Genetic Evidence

Transcription factors of the NAC family are known to be involved in various growth or developmental processes and in regulation of response to environmental stresses. In the present study, we report that Arabidopsis ATAF1 is a negative regulator of defense responses against both necrotrophic fungal and bacterial pathogens. Expression of ATAF1 was downregulated after infection with Botrytis cinerea or Pseudomonas syringae pv. tomato or after treatment with salicylic acid (SA), jasmonic acid, and 1-amino cyclopropane-1-carboxylic acid (the precursor of ethylene biosynthesis). Transgenic plants that overexpress the ATAF1 gene (ATAF1-OE) showed increased susceptibility while expression of an ATAF1 chimeric repressor construct (ATAF1-SRDX) exhibited enhanced resistance to P. syringae pv. tomato DC3000, B. cinerea, and Alternaria brassicicola. The ataf1 mutant plants showed no significant resistance against the pathogens tested. After inoculation with B. cinerea or P. syringae pv. tomato DC3000, expressions of defense-related genes PR-1, PR-5. and PDF1.2 were upregulated in the ATAF1-SRDX plants but attenuated or unchanged in the ATAF1-OE plants. In ATAF1-OE plants, SA-induced expression of pathogenesis-related genes and disease resistance against P. syringae pv. tomato DC3000 was partially suppressed. Increased levels of reactive oxygen species (i.e., H2O2 and superoxide anion) accumulated only in the ATAF1-OE but not in the ATAF1-SRDX plants after Botrytis spp. infection. Our studies provide direct genetic evidence for the role of ATAF1 as a negative regulator of defense response against different type of pathogens.

scholarly journals NINJA-Associated ERF19 Negatively Regulates Arabidopsis Pattern-Triggered Immunity

2017 ◽  
Author(s):  
Pin-Yao Huang ◽  
Jingsong Zhang ◽  
Beier Jiang ◽  
Jhong-He Yu ◽  
Yu-Ping Lu ◽  
...  
Keyword(s):  
Pseudomonas Syringae ◽  
Defense Responses ◽  
Negative Regulator ◽  
Fine Tuning ◽  
Ethylene Response Factor ◽  
Negative Role ◽  
Erf Family ◽  
Complex Signaling ◽  
Molecular Patterns

ABSTRACTRecognition of microbe-associated molecular patterns (MAMPs) derived from invading pathogens by plant pattern recognition receptors (PRRs) initiates defense responses known as pattern-triggered immunity (PTI). Transcription factors (TFs) orchestrate the onset of PTI through complex signaling networks. Here, we characterize the function of ERF19, a member of the Arabidopsis thaliana ethylene response factor (ERF) family. ERF19 was found to act as a negative regulator of PTI against Botrytis cinerea and Pseudomonas syringae pv. tomato DC3000 (Pst). Notably, overexpression of ERF19 increased plant susceptibility to these pathogens and repressed MAMP-induced PTI outputs. In contrast, expression of the chimeric dominant repressor ERF19-SRDX boosted PTI activation, conferred increased resistance to B. cinerea, and enhanced elf18-triggered immunity against Pst. Consistent with a negative role of ERF19 in PTI, MAMP-mediated growth inhibition was respectively weakened or augmented in lines overexpressing ERF19 or expressing ERF19-SRDX. Moreover, we demonstrate that the transcriptional repressor Novel INteractor of JAZ (NINJA) associates with and represses the function of ERF19. Our work reveals ERF19 as a key player in a buffering mechanism to avoid defects imposed by over-activation of PTI and a potential role for NINJA in fine-tuning ERF19-mediated regulation.

scholarly journals The Arabidopsis thaliana JASMONATE INSENSITIVE 1 Gene Is Required for Suppression of Salicylic Acid-Dependent Defenses During Infection by Pseudomonas syringae

2006 ◽  
Vol 19 (7) ◽  
pp. 789-800 ◽  
Author(s):  
Neva Laurie-Berry ◽  
Vinita Joardar ◽  
Ian H. Street ◽  
Barbara N. Kunkel
Keyword(s):  
Arabidopsis Thaliana ◽  
Salicylic Acid ◽  
Pseudomonas Syringae ◽  
Plant Pathogens ◽  
Symptom Development ◽  
Tomato Dc3000 ◽  
Jasmonate Signaling ◽  
Pathogenesis Related ◽  
Elevated Expression

Many plant pathogens suppress antimicrobial defenses using virulence factors that modulate endogenous host defenses. The Pseudomonas syringae phytotoxin coronatine (COR) is believed to promote virulence by acting as a jasmonate analog, because COR-insensitive 1 (coi1) Arabidopsis thaliana and tomato mutants are impaired in jasmonate signaling and exhibit reduced susceptibility to P. syringae. To further investigate the role of jasmonate signaling in disease development, we analyzed several jasmonate-insensitive A. thaliana mutants for susceptibility to P. syringae pv. tomato strain DC3000 and sensitivity to COR. Jasmonate-insensitive1 (jin1) mutants exhibit both reduced susceptibility to P. syringae pv. tomato DC3000 and reduced sensitivity to COR, whereas jasmonate-resistant 1 (jar1) plants exhibit wild-type responses to both COR and P. syringae pv. tomato DC3000. A jin1 jar1 double mutant does not exhibit enhanced jasmonate insensitivity, suggesting that JIN1 functions downstream of jasmonic acid-amino acid conjugates synthesized by JAR1. Reduced disease susceptibility in jin1 mutants is correlated with elevated expression of pathogenesis-related 1(PR-1) and is dependent on accumulation of salicylic acid (SA). We also show that JIN1 is required for normal P. syringae pv. tomato DC3000 symptom development through an SA-independent mechanism. Thus,P. syringae pv. tomatoDC3000 appears to utilize COR to manipulate JIN1-dependent jasmonate signaling both to suppress SA-mediated defenses and to promote symptom development.

scholarly journals SKIP Silencing Decreased Disease Resistance Against Botrytis cinerea and Pseudomonas syringae pv. tomato DC3000 in Tomato

2020 ◽  
Vol 11 ◽  
Author(s):  
Huijuan Zhang ◽  
Longfei Yin ◽  
Fengming Song ◽  
Ming Jiang
Keyword(s):  
Disease Resistance ◽  
Botrytis Cinerea ◽  
Pseudomonas Syringae ◽  
Defense Responses ◽  
Vital Role ◽  
Pcr Analysis ◽  
Virus Induced Gene Silencing ◽  
Tomato Dc3000 ◽  
Significant Difference ◽  
Direct Genetic Evidence

SKIP, a component of the spliceosome, is involved in numerous signaling pathways. However, there is no direct genetic evidence supporting the function of SKIP in defense responses. In this paper, two SKIPs, namely, SlSKIP1a and SlSKIP1b, were analyzed in tomato. qRT-PCR analysis showed that the SlSKIP1b expression was triggered via Pseudomonas syringae pv. tomato (Pst) DC3000 and Botrytis cinerea (B. cinerea), together with the defense-associated signals. In addition, the functions of SlSKIP1a and SlSKIP1b in disease resistance were analyzed in tomato through the virus-induced gene silencing (VIGS) technique. VIGS-mediated SlSKIP1b silencing led to increased accumulation of reactive oxygen species (ROS), along with the decreased expression of defense-related genes (DRGs) after pathogen infection, suggesting that it reduced B. cinerea and Pst DC3000 resistance. There was no significant difference in B. cinerea and Pst DC3000 resistance in TRV-SlSKIP1a-infiltrated plants compared with the TRV-GUS-silencing counterparts. As suggested by the above findings, SlSKIP1b plays a vital role in disease resistance against pathogens possibly by regulating the accumulation of ROS as well as the expression of DRGs.

scholarly journals The MAP Kinase Kinase MKK2 Affects Disease Resistance in Arabidopsis

2007 ◽  
Vol 20 (5) ◽  
pp. 589-596 ◽  
Author(s):  
Günter Brader ◽  
Armin Djamei ◽  
Markus Teige ◽  
E. Tapio Palva ◽  
Heribert Hirt
Keyword(s):  
Disease Resistance ◽  
Pseudomonas Syringae ◽  
Stress Responses ◽  
Plant Disease Resistance ◽  
Map Kinases ◽  
Defense Responses ◽  
Alternaria Brassicicola ◽  
Tomato Dc3000 ◽  
Altered Expression ◽  
Expression Of Genes

The Arabidopsis mitogen-activated protein kinase (MAPK) kinase 2 (MKK2) was shown to mediate cold and salt stress responses through activation of the two MAP kinases MPK4 and MPK6. Transcriptome analysis of plants expressing constitutively active MKK2 (MKK2-EE plants) showed altered expression of genes induced by abiotic stresses but also a significant number of genes involved in defense responses. Both MPK4 and MPK6 became rapidly activated upon Pseudomonas syringae pv. tomato DC3000 infection and MKK2-EE plants showed enhanced levels of MPK4 activation. Although MKK2-EE plants shared enhanced expression of genes encoding enzymes of ethylene (ET) and jasmonic acid (JA) synthesis, ET, JA, and salicylic acid (SA) levels did not differ dramatically from those of wild-type or mkk2-null plants under ambient growth conditions. Upon P. syringae pv. tomato DC3000 infection, however, MKK2-EE plants showed reduced increases of JA and SA levels. These results indicate that MKK2 is involved in regulating hormone levels in response to pathogens. MKK2-EE plants were more resistant to infection by P. syringae pv. tomato DC3000 and Erwinia carotovora subsp. carotovora, but showed enhanced sensitivity to the fungal necrotroph Alternaria brassicicola. Our data indicate that MKK2 plays a role in abiotic stress tolerance and plant disease resistance.

scholarly journals A revised model for the role of GacS/GacA in regulating type III secretion by Pseudomonas syringae pv. tomato DC3000

2019 ◽  
Vol 21 (1) ◽  
pp. 139-144 ◽  
Author(s):  
Megan R. O’Malley ◽  
Ching‐Fang Chien ◽  
Scott C. Peck ◽  
Nai‐Chun Lin ◽  
Jeffrey C. Anderson
Keyword(s):  
Pseudomonas Syringae ◽  
Type Iii Secretion ◽  
Tomato Dc3000 ◽  
Type Iii

scholarly journals Identification and Characterization of a Well-Defined Series of Coronatine Biosynthetic Mutants of Pseudomonas syringae pv. tomato DC3000

2004 ◽  
Vol 17 (2) ◽  
pp. 162-174 ◽  
Author(s):  
David M. Brooks ◽  
Gustavo Hernández-Guzmán ◽  
Andrew P. Kloek ◽  
Francisco Alarcón-Chaidez ◽  
Aswathy Sreedharan ◽  
...  
Keyword(s):  
Pseudomonas Syringae ◽  
High Performance ◽  
Tomato Dc3000 ◽  
Disease Symptoms ◽  
Coronafacic Acid ◽  
Tn5 Mutants ◽  
Cor Genes ◽  
Identification And Characterization

To identify Pseudomonas syringae pv. tomato genes involved in pathogenesis, we carried out a screen for Tn5 mutants of P. syringae pv. tomato DC3000 with reduced virulence on Arabidopsis thaliana. Several mutants defining both known and novel virulence loci were identified. Six mutants contained insertions in biosynthetic genes for the phytotoxin coronatine (COR). The P. syringae pv. tomato DC3000 COR genes are chromosomally encoded and are arranged in two separate clusters, which encode enzymes responsible for the synthesis of coronafacic acid (CFA) or coronamic acid (CMA), the two defined intermediates in COR biosynthesis. High-performance liquid chromatography fractionation and exogenous feeding studies confirmed that Tn5 insertions in the cfa and cma genes disrupt CFA and CMA biosynthesis, respectively. All six COR biosynthetic mutants were significantly impaired in their ability to multiply to high levels and to elicit disease symptoms on A. thaliana plants. To assess the relative contributions of CFA, CMA, and COR in virulence, we constructed and characterized cfa6 cmaA double mutant strains. These exhibited virulence phenotypes on A. thalliana identical to those observed for the cmaA or cfa6 single mutants, suggesting that reduced virulence of these mutants on A. thaliana is caused by the absence of the intact COR toxin. This is the first study to use biochemically and genetically defined COR mutants to address the role of COR in pathogenesis.

scholarly journals Signal Signature and Transcriptome Changes of Arabidopsis During Pathogen and Insect Attack

2005 ◽  
Vol 18 (9) ◽  
pp. 923-937 ◽  
Author(s):  
Martin De Vos ◽  
Vivian R. Van Oosten ◽  
Remco M. P. Van Poecke ◽  
Johan A. Van Pelt ◽  
Maria J. Pozo ◽  
...  
Keyword(s):  
Gene Expression ◽  
Pseudomonas Syringae ◽  
Defense Response ◽  
Frankliniella Occidentalis ◽  
Pieris Rapae ◽  
Expression Profiles ◽  
Defense Responses ◽  
Alternaria Brassicicola ◽  
Microbial Pathogens ◽  
Primary Role

Plant defenses against pathogens and insects are regulated differentially by cross-communicating signaling pathways in which salicylic acid (SA), jasmonic acid (JA), and ethylene (ET) play key roles. To understand how plants integrate pathogen- and insect-induced signals into specific defense responses, we monitored the dynamics of SA, JA, and ET signaling in Arabidopsis after attack by a set of microbial pathogens and herbivorous insects with different modes of attack. Arabidopsis plants were exposed to a pathogenic leaf bacterium (Pseudomonas syringae pv. tomato), a pathogenic leaf fungus (Alternaria brassicicola), tissue-chewing caterpillars (Pieris rapae), cell-content-feeding thrips (Frankliniella occidentalis), or phloem-feeding aphids (Myzus persicae). Monitoring the signal signature in each plant-attacker combination showed that the kinetics of SA, JA, and ET production varies greatly in both quantity and timing. Analysis of global gene expression profiles demonstrated that the signal signature characteristic of each Arabidopsis-attacker combination is orchestrated into a surprisingly complex set of transcriptional alterations in which, in all cases, stress-related genes are overrepresented. Comparison of the transcript profiles revealed that consistent changes induced by pathogens and insects with very different modes of attack can show considerable overlap. Of all consistent changes induced by A. brassicicola, Pieris rapae, and F. occidentalis, more than 50% also were induced consistently by P. syringae. Notably, although these four attackers all stimulated JA biosynthesis, the majority of the changes in JA-responsive gene expression were attacker specific. All together, our study shows that SA, JA, and ET play a primary role in the orchestration of the plant's defense response, but other regulatory mechanisms, such as pathway cross-talk or additional attacker-induced signals, eventually shape the highly complex attacker-specific defense response.

scholarly journals Characterization of a Novel, Defense-Related Arabidopsis Mutant, cir1, Isolated By Luciferase Imaging

2002 ◽  
Vol 15 (6) ◽  
pp. 557-566 ◽  
Author(s):  
Shane L. Murray ◽  
Catherine Thomson ◽  
Andrea Chini ◽  
Nick D. Read ◽  
Gary J. Loake
Keyword(s):  
Signaling Pathways ◽  
Pseudomonas Syringae ◽  
Constitutive Expression ◽  
Bacterial Pathogen ◽  
Negative Regulator ◽  
Reactive Oxygen Intermediate ◽  
Peronospora Parasitica ◽  
Tomato Dc3000 ◽  
Pathogen Invasion ◽  
Arabidopsis Mutant

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 (npr1, 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, cir1-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.

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