scholarly journals The Role of Nitric Oxide-Induced ATILL6 in Growth and Disease Resistance in Arabidopsis thaliana

2021 ◽  
Vol 12 ◽  
Author(s):  
Murtaza Khan ◽  
Tiba Nazar Ibrahim Al Azawi ◽  
Anjali Pande ◽  
Bong-Gyu Mun ◽  
Da-Sol Lee ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Plant Growth ◽  
Pseudomonas Syringae ◽  
Systemic Acquired Resistance ◽  
Acquired Resistance ◽  
R Gene ◽  
Transcript Accumulation ◽  
Positive Role ◽  
Basal Defense

Nitric oxide (NO) is a signaling molecule that regulates various processes, including plant growth and development, immunity, and environmental interactions. Using high throughput RNA-seq data, we explored the role of the NO-induced ATILL6 gene in plant growth and defense using functional genomics. The atill6 mutant and wild-types were challenged with either oxidative (H2O2, MV) or nitro-oxidative (CySNO, GSNO) stress conditions, and the phenotypic results showed that ATILL6 gene differentially regulates cotyledon development frequency (CDF) as well as the root and shoot lengths of the plants. To investigate whether ATILL6 plays a role in plant basal or resistance (R)-gene-mediated defense, the plants were challenged with either virulent or avirulent strains of Pseudomonas syringae pathovar tomato (Pst) DC3000. The atill6 line showed a susceptible phenotype, higher pathogen growth, and highly reduced transcript accumulation of PR1 and PR2 genes. These results suggested that ATILL6 positively regulates plant basal defense. Furthermore, after the inoculation of atill6 with avirulent Pst (DC3000), the expressions of the PR1 and PR2 genes decreased, suggesting a positive role in R-gene-mediated resistance in protecting the plant from further spread of disease. We also investigated the role of ATILL6 in systemic acquired resistance (SAR), and the results showed that ATILL6 positively regulates SAR, as the mutant line atill6 has significantly (p ≤ 0.05) lower transcript accumulation of PR, G3DPH, and AZI genes. Overall, these results indicate that the NO-induced ATILL6 gene differentially regulates plant growth and positively regulates plant basal defense, R-gene-mediated resistance, and SAR.

scholarly journals Arabidopsis Clade I TGA Transcription Factors Regulate Plant Defenses in an NPR1-Independent Fashion

2012 ◽  
Vol 25 (11) ◽  
pp. 1459-1468 ◽  
Author(s):  
Heather L. Shearer ◽  
Yu Ti Cheng ◽  
Lipu Wang ◽  
Jinman Liu ◽  
Patrick Boyle ◽  
...  
Keyword(s):  
Transcription Factors ◽  
Pseudomonas Syringae ◽  
Systemic Acquired Resistance ◽  
Acquired Resistance ◽  
Defense Responses ◽  
R Gene ◽  
Triple Mutant ◽  
Transcriptional Reprogramming ◽  
Tga Factors ◽  
Hyaloperonospora Arabidopsidis

Transcriptional reprogramming during induction of salicylic acid (SA)-mediated defenses is regulated primarily by NPR1 (NONEXPRESSOR OF PATHOGENESIS-RELATED GENES 1), likely through interactions with TGA bZIP transcription factors. To ascertain the contributions of clade I TGA factors (TGA1 and TGA4) to defense responses, a tga1-1 tga4-1 double mutant was constructed and challenged with Pseudomonas syringae and Hyaloperonospora arabidopsidis. Although the mutant displayed enhanced susceptibility to virulent P. syringae, it was not compromised in systemic acquired resistance against this pathogen or resistance against avirulent H. arabidopsidis. Microarray analysis of nonelicited and SA-treated plants indicated that clade I TGA factors regulate fewer genes than NPR1. Approximately half of TGA-dependent genes were regulated by NPR1 but, in all cases, the direction of change was opposite in the two mutants. In support of the microarray data, the NPR1-independent disease resistance observed in the autoimmune resistance (R) gene mutant snc1 is partly compromised by tga1-1 tga4-1 mutations, and a triple mutant of clade I TGA factors with npr1-1 is more susceptible than either parent. These results suggest that clade I TGA factors are required for resistance against virulent pathogens and avirulent pathogens mediated by at least some R gene specificities, acting substantially through NPR1-independent pathways.

scholarly journals Trichoderma asperelloides enhances local and systemic acquired resistance response under low nitrate nutrition in Arabidopsis

2018 ◽  
Author(s):  
Aakanksha Wany ◽  
Pradeep K. Pathak ◽  
Alisdair R Fernie ◽  
Kapuganti Jagadis Gupta
Keyword(s):  
Pseudomonas Syringae ◽  
Systemic Acquired Resistance ◽  
N Uptake ◽  
Acquired Resistance ◽  
Marker Genes ◽  
Defense Gene Expression ◽  
Resistance Response ◽  
Defense Gene ◽  
Protein Levels

AbstractNitrogen (N) is essential for growth, development and defense but, how low N affects defense and the role of Trichoderma in enhancing defense under low nitrate is not known. Low nitrate fed Arabidopsis plants displayed reduced growth and compromised local and systemic acquired resistance responses when infected with both avirulent and virulent Pseudomonas syringae DC3000. These responses were enhanced in the presence of Trichoderma. The mechanism of increased local and systemic acquired resistance mediated by Trichoderma involved increased N uptake and enhanced protein levels via modulation of nitrate transporter genes. The nrt2.1 mutant is compromised in local and systemic acquired resistance responses suggesting a link between enhanced N transport and defense. Enhanced N uptake was mediated by Trichoderma elicited nitric oxide (NO). Low NO producing nia1,2 mutant and nsHb+ over expressing lines were unable to induce nitrate transporters and thereby compromised defense in the presence of Trichoderma under low N suggesting a signaling role of Trichoderma elicited NO. Trichoderma also induced SA and defense gene expression under low N. The SA deficient NahG transgenic line and the npr1 mutant were also compromised in Trichoderma-mediated local and systemic acquired resistance responses. Collectively our results indicated that the mechanism of enhanced plant defense under low N mediated by Trichoderma involves NO, ROS, SA production as well as the induction of NRT and marker genes for systemic acquired resistance.One-sentence summaryTrichoderma enhances local and systemic acquired resistance under low nitrate nutrition

Role of Salicylic Acid and NIM1/NPR1 in Race-Specific Resistance in Arabidopsis

Genetics ◽  
2002 ◽  
Vol 161 (2) ◽  
pp. 803-811
Author(s):  
Gregory J Rairdan ◽  
Terrence P Delaney
Keyword(s):  
Salicylic Acid ◽  
Pseudomonas Syringae ◽  
Leucine Zipper ◽  
Systemic Acquired Resistance ◽  
Specific Resistance ◽  
Strong Dependence ◽  
Acquired Resistance ◽  
R Genes ◽  
Resistance Response

Abstract Salicylic acid (SA) and the NIM1/NPR1 protein have both been demonstrated to be required for systemic acquired resistance (SAR) and implicated in expression of race-specific resistance. In this work, we analyzed the role that each of these molecules play in the resistance response triggered by members of two subclasses of resistance (R) genes, members of which recognize unrelated pathogens. We tested the ability of TIR and coiled-coil-class (also known as leucine-zipper-class) R genes to confer resistance to Pseudomonas syringae pv. tomato or Peronospora parasitica in SA-depleted (NahG) and nim1/npr1 plants. We found that all of the P. syringae pv. tomato-specific R genes tested were dependent upon SA accumulation, while none showed strong dependence upon NIM1/NPR1 activity. A similar SA dependence was observed for the P. parasitica TIR and CC-class R genes RPP5 and RPP8, respectively. However, the P. parasitica-specific R genes differed in their requirement for NIM1/NPR1, with just RPP5 depending upon NIM1/NPR1 activity for effectiveness. These data are consistent with the hypothesis that at least in Arabidopsis, SA accumulation is necessary for the majority of R-gene-triggered resistance, while the role of NIM1/NPR in race-specific resistance is limited to resistance to P. parasitica mediated by TIR-class R genes.

scholarly journals Pipecolic Acid Is Induced in Barley upon Infection and Triggers Immune Responses Associated with Elevated Nitric Oxide Accumulation

2019 ◽  
Vol 32 (10) ◽  
pp. 1303-1313 ◽  
Author(s):  
Miriam Lenk ◽  
Marion Wenig ◽  
Kornelia Bauer ◽  
Florian Hug ◽  
Claudia Knappe ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Immune Responses ◽  
Pseudomonas Syringae ◽  
Systemic Acquired Resistance ◽  
Acquired Resistance ◽  
Bacterial Pathogen ◽  
Pipecolic Acid ◽  
Systemic Immunity ◽  
Exogenous Application ◽  
Barley Leaves

Pipecolic acid (Pip) is an essential component of systemic acquired resistance, priming resistance in Arabidopsis thaliana against (hemi)biotrophic pathogens. Here, we studied the potential role of Pip in bacteria-induced systemic immunity in barley. Exudates of barley leaves infected with the systemic immunity–inducing pathogen Pseudomonas syringae pv. japonica induced immune responses in A. thaliana. The same leaf exudates contained elevated Pip levels compared with those of mock-treated barley leaves. Exogenous application of Pip induced resistance in barley against the hemibiotrophic bacterial pathogen Xanthomonas translucens pv. cerealis. Furthermore, both a systemic immunity–inducing infection and exogenous application of Pip enhanced the resistance of barley against the biotrophic powdery mildew pathogen Blumeria graminis f. sp. hordei. In contrast to a systemic immunity-inducing infection, Pip application did not influence lesion formation by a systemically applied inoculum of the necrotrophic fungus Pyrenophora teres. Nitric oxide (NO) levels in barley leaves increased after Pip application. Furthermore, X. translucens pv. cerealis induced the accumulation of superoxide anion radicals and this response was stronger in Pip-pretreated compared with mock-pretreated plants. Thus, the data suggest that Pip induces barley innate immune responses by triggering NO and priming reactive oxygen species accumulation.

scholarly journals GmRAR1 and GmSGT1 Are Required for Basal, R Gene–Mediated and Systemic Acquired Resistance in Soybean

2009 ◽  
Vol 22 (1) ◽  
pp. 86-95 ◽  
Author(s):  
Da-Qi Fu ◽  
Said Ghabrial ◽  
Aardra Kachroo
Keyword(s):  
Pseudomonas Syringae ◽  
Systemic Acquired Resistance ◽  
Soybean Mosaic Virus ◽  
Acquired Resistance ◽  
Bacterial Pathogen ◽  
R Gene ◽  
Extreme Resistance ◽  
Basal Resistance ◽  
Effector Triggered Immunity ◽  
Specific Proteins

RAR1, SGT1, and HSP90 are important components of effector-triggered immunity (ETI) in diverse plants, where RAR1 and SGT1 are thought to serve as HSP90 co-chaperones. We show that ETI in soybean requires RAR1 and SGT1 but not HSP90. Rsv1-mediated extreme resistance to Soybean mosaic virus (SMV) and Rpg-1b-mediated resistance to Pseudomonas syringae were compromised in plants silenced for GmRAR1 and GmSGT1-2 but not GmHSP90. This suggests that RAR1- or SGT1-dependant signaling is not always associated with a dependence on HSP90. Unlike in Arabidopsis, SGT1 in soybean also mediates ETI against the bacterial pathogen P. syringae. Similar to Arabidopsis, soybean RAR1 and SGT1 proteins interact with each other and two related HSP90 proteins. Plants silenced for GmHSP90 genes or GmRAR1 exhibited altered morphology, suggesting that these proteins also contribute to developmental processes. Silencing GmRAR1 and GmSGT1-2 impaired resistance to virulent bacteria and systemic acquired resistance (SAR) in soybean as well. Because the Arabidopsis rar1 mutant also showed a defect in SAR, we conclude that RAR1 and SGT1 serve as a point of convergence for basal resistance, ETI, and SAR. We demonstrate that, although soybean defense signaling pathways recruit structurally conserved components, they have distinct requirements for specific proteins.

scholarly journals Activation of an EDS1-Mediated R-Gene Pathway in the snc1 Mutant Leads to Constitutive, NPR1-Independent Pathogen Resistance

2001 ◽  
Vol 14 (10) ◽  
pp. 1131-1139 ◽  
Author(s):  
Xin Li ◽  
Joseph D. Clarke ◽  
Yuelin Zhang ◽  
Xinnian Dong
Keyword(s):  
Pseudomonas Syringae ◽  
Systemic Acquired Resistance ◽  
Acquired Resistance ◽  
Pathogen Resistance ◽  
R Gene ◽  
Signal Molecule ◽  
Gene Pathway ◽  
Constitutive Resistance ◽  
Resistance Pathway ◽  
Arabidopsis Mutant

The Arabidopsis NPR1 protein is an essential regulatory component of systemic acquired resistance (SAR). Mutations in the NPR1 gene completely block the induction of SAR by signals such as salicylic acid (SA). An Arabidopsis mutant, snc1 (suppressor of npr1-1, constitutive 1), was isolated in a screen for suppressors of npr1-1. In the npr1-1 background, the snc1 mutation resulted in constitutive resistance to Pseudomonas syringae maculicola ES4326 and Peronospora parasitica Noco2. High levels of SA were detected in the mutant and shown to be required for manifestation of the snc1 phenotype. The snc1 mutation was mapped to the RPP5 resistance (R) gene cluster and the eds1 mutation that blocks RPP5-mediated resistance suppressed snc1. These data suggest that a RPP5-related resistance pathway is activated constitutively in snc1. This pathway does not employ NPR1 but requires the signal molecule SA and the function of EDS1. Moreover, in snc1, constitutive resistance is conferred in the absence of cell death, which is often associated with R-gene mediated resistance.

scholarly journals Differential expression of AtWAKL10 in response to nitric oxide suggests a putative role in biotic and abiotic stress responses

PeerJ ◽  
2019 ◽  
Vol 7 ◽  
pp. e7383
Author(s):  
Phearom Bot ◽  
Bong-Gyu Mun ◽  
Qari Muhammad Imran ◽  
Adil Hussain ◽  
Sang-Uk Lee ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Abiotic Stress ◽  
Pseudomonas Syringae ◽  
Stress Responses ◽  
Abiotic Stresses ◽  
Nitrosative Stress ◽  
Abiotic Stress Tolerance ◽  
Biotic And Abiotic Stress ◽  
Transcript Accumulation

Plant defense against pathogens and abiotic stresses is regulated differentially by communicating signal transduction pathways in which nitric oxide (NO) plays a key role. Here, we show the biological role of Arabidopsis thaliana wall-associated kinase (AtWAK) Like10 (AtWAKL10) that exhibits greater than a 100-fold change in transcript accumulation in response to the NO donor S-nitroso-L-cysteine (CysNO), identified from high throughput RNA-seq based transcriptome analysis. Loss of AtWAKL10 function showed a similar phenotype to wild type (WT) with, however, less branching. The growth of atwakl10 on media supplemented with oxidative or nitrosative stress resulted in differential results with improved growth following treatment with CysNO but reduced growth in response to S-nitrosoglutatione (GSNO) and methyl-viologen. Further, atwakl10 plants exhibited increased susceptibility to virulent Pseudomonas syringae pv tomato (Pst) DC3000 with a significant increase in pathogen growth and decrease in PR1 transcript accumulation compared to WT overtime. Similar results were found in response to Pst DC3000 avrB, resulting in increased cell death as shown by increased electrolyte leakage in atwakl10. Furthermore, atwakl10 also showed increased reactive oxygen species accumulation following Pst DC3000 avrB inoculation. Promoter analysis of AtWAKL10 showed transcription factor (TF) binding sites for biotic and abiotic stress-related TFs. Further investigation into the role of AtWAKL10 in abiotic stresses showed that following two weeks water-withholding drought condition most of the atwakl10 plants got wilted; however, the majority (60%) of these plants recovered following re-watering. In contrast, in response to salinity stress, atwakl10 showed reduced germination under 150 mM salt stress compared to WT, suggesting that NO-induced AtWAKL10 differentially regulates different abiotic stresses. Taken together, this study further elucidates the importance of NO-induced changes in gene expression and their role in plant biotic and abiotic stress tolerance.

Isolation and Characterization of Broad-Spectrum Disease-Resistant Arabidopsis Mutants

Genetics ◽  
2002 ◽  
Vol 160 (4) ◽  
pp. 1661-1671
Author(s):  
Klaus Maleck ◽  
Urs Neuenschwander ◽  
Rebecca M Cade ◽  
Robert A Dietrich ◽  
Jeffery L Dangl ◽  
...  
Keyword(s):  
Pseudomonas Syringae ◽  
Systemic Acquired Resistance ◽  
Acquired Resistance ◽  
Constitutive Expression ◽  
Firefly Luciferase ◽  
Marker Genes ◽  
Arabidopsis Mutants ◽  
Isolation And Characterization ◽  
Firefly Luciferase Gene

Abstract To identify Arabidopsis mutants that constitutively express systemic acquired resistance (SAR), we constructed reporter lines expressing the firefly luciferase gene under the control of the SAR-inducible PR-1 promoter (PR-1/luc). After EMS mutagenesis of a well-characterized transgenic line, we screened 250,000 M2 plants for constitutive expression of the reporter gene in vivo. From a mutant collection containing several hundred putative mutants, we concentrated on 16 mutants lacking spontaneous hypersensitive response (HR) cell death. We mapped 4 of these constitutive immunity (cim) mutants to chromosome arms. Constitutive expression of disease resistance was established by analyzing responses to virulent Peronospora parasitica and Pseudomonas syringae strains, by RNA blot analysis for endogenous marker genes, and by determination of salicylic acid levels in the mutants. The variety of the cim phenotypes allowed us to define distinct steps in both the canonical SAR signaling pathway and a separate pathway for resistance to Erysiphe cichoracearum, active in only a subset of the mutants.

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