scholarly journals Hypersensitive Cell Death and Papilla Formation in Barley Attacked by the Powdery Mildew Fungus Are Associated with Hydrogen Peroxide but Not with Salicylic Acid Accumulation

1999 ◽  
Vol 119 (4) ◽  
pp. 1251-1260 ◽  
Author(s):  
Ralph Hückelhoven ◽  
József Fodor ◽  
Christine Preis ◽  
Karl-Heinz Kogel
Keyword(s):  
Hydrogen Peroxide ◽  
Cell Death ◽  
Salicylic Acid ◽  
Powdery Mildew ◽  
Powdery Mildew Fungus ◽  
Hypersensitive Cell Death ◽  
Acid Accumulation ◽  
Salicylic Acid Accumulation ◽  
Papilla Formation

scholarly journals Silencing of RBOHF2 Causes Leaf Age–Dependent Accelerated Senescence, Salicylic Acid Accumulation, and Powdery Mildew Resistance in Barley

2017 ◽  
Vol 30 (11) ◽  
pp. 906-918 ◽  
Author(s):  
Denise Pereira Torres ◽  
Reinhard K. Proels ◽  
Harald Schempp ◽  
Ralph Hückelhoven
Keyword(s):  
Salicylic Acid ◽  
Powdery Mildew ◽  
Leaf Age ◽  
Leaf Tissue ◽  
Defense Gene Expression ◽  
Powdery Mildew Fungus ◽  
Basal Resistance ◽  
Acid Accumulation ◽  
Salicylic Acid Accumulation ◽  
Leaf Level

Plant RBOH (RESPIRATORY BURST OXIDASE HOMOLOGS)-type NADPH oxidases produce superoxide radical anions and have a function in developmental processes and in response to environmental challenges. Barley RBOHF2 has diverse reported functions in interaction with the biotrophic powdery mildew fungus Blumeria graminis f. sp. hordei. Here, we analyzed, in detail, plant leaf level- and age-specific susceptibility of stably RBOHF2-silenced barley plants. This revealed enhanced susceptibility to fungal penetration of young RBOHF2-silenced leaf tissue but strongly reduced susceptibility of older leaves when compared with controls. Loss of susceptibility in old RBOHF2-silenced leaves was associated with spontaneous leaf-tip necrosis and constitutively elevated levels of free and conjugated salicylic acid. Additionally, these leaves more strongly expressed pathogenesis-related genes, both constitutively and during interaction with B. graminis f. sp. hordei. Together, this supports the idea that barley RBOHF2 contributes to basal resistance to powdery mildew infection in young leaf tissue but is required to control leaf cell death, salicylic acid accumulation, and defense gene expression in older leaves, explaining leaf age–specific resistance of RBOHF2-silenced barley plants.

Hydrogen peroxide promotes programmed cell death and salicylic acid accumulation during the induced production of sesquiterpenes in cultured cell suspensions of Aquilaria sinensis

2015 ◽  
Vol 42 (4) ◽  
pp. 337 ◽  
Author(s):  
Juan Liu ◽  
Yanhong Xu ◽  
Zheng Zhang ◽  
Jianhe Wei
Keyword(s):  
Hydrogen Peroxide ◽  
Cell Death ◽  
Salicylic Acid ◽  
Programmed Cell Death ◽  
Cell Suspensions ◽  
Valuable Insight ◽  
Aquilaria Sinensis ◽  
Defensive Reaction ◽  
Cultured Cell ◽  
Salicylic Acid Accumulation

Aquilaria sinensis (Lour.) Gilg produces a highly valuable agarwood characterised by a diverse array of sesquiterpenes and chromone derivatives that can protect wounded trees against potential herbivores and pathogens. A defensive reaction on the part of the plant has been proposed as the key reason for agarwood formation, but the issue of whether programmed cell death (PCD), an important process of plant immune responding, is involved in agarwood formation, still needs to be clarified. In this study, treatment of cultured cell suspensions with hydrogen peroxide (H2O2) induced the production of sesquiterpenes due to endogenous accumulation of salicylic acid (SA) and elevations in the expression of sesquiterpene biosynthetic genes. Moreover, PCD was stimulated by H2O2 in cultured cell suspensions of A. sinensis due to the induction of caspase activity, upregulated expression of metacaspases and cytochrome c, and SA accumulation. Our findings demonstrate for the first time that H2O2 stimulates PCD, SA accumulation and sesquiterpene production in cultured cell suspensions of A. sinensis. Furthermore, results from this study provide a valuable insight into investigations of the potential interactions between sesquiterpene synthesis and PCD during agarwood formation.

Overexpression of BAK1 causes salicylic acid accumulation and deregulation of cell death control genes

2017 ◽  
Vol 484 (4) ◽  
pp. 781-786 ◽  
Author(s):  
Sun Young Kim ◽  
Yun Shang ◽  
Se-Hwan Joo ◽  
Seong-Ki Kim ◽  
Kyoung Hee Nam
Keyword(s):  
Cell Death ◽  
Salicylic Acid ◽  
Acid Accumulation ◽  
Salicylic Acid Accumulation

scholarly journals Tissue-Specific Superoxide Generation at Interaction Sites in Resistant and Susceptible Near-Isogenic Barley Lines Attacked by the Powdery Mildew Fungus (Erysiphe graminis f. sp. hordei)

1998 ◽  
Vol 11 (4) ◽  
pp. 292-300 ◽  
Author(s):  
Ralph Hückelhoven ◽  
Karl-Heinz Kogel
Keyword(s):  
Cell Death ◽  
Powdery Mildew ◽  
Mesophyll Cell ◽  
Epidermal Cells ◽  
Erysiphe Graminis ◽  
Time Range ◽  
Powdery Mildew Fungus ◽  
Hypersensitive Cell Death ◽  
Interaction Sites ◽  
Nbt Reduction

The pathogenesis-related, azide-insensitive generation of superoxide anions (O2 -) was comparatively analyzed in near-isogenic barley (Hordeum vulgare cv. Pallas) lines carrying the powdery mildew (Erysiphe graminis f. sp. hordei) resistance genes Mla12, Mlg, and mlo5, respectively, by the microscopic detection of nitroblue tetra-zolium (NBT) reduction to dark blue formazan dyes. These genes govern fungal arrest at different stages of the interaction: (i) at the penetration stage within cell wall appositions (papillae) leaving the attacked cell alive (mlo); (ii) within papillae of cells that subsequently undergo a hypersensitive cell death (HR) (Mlg); or (iii) after penetration by a subsequent HR (Mla12). The susceptible parent line Pallas showed a transient O2 - generation in penetrated epidermal cells at 18 h after inoculation (hai), whereas epidermal cells of the resistant BCPMla12 produced O2 - over a longer time range (by 18 to 36 hai) preceding cell death. No oxidative burst was detected in association with penetration resistance due to effective papillae (BCPMlg and BCPmlo5) although Mlg specified an HR subsequent to fungal arrest. Hence, O2 - generation in attacked epidermal cells was a result of fungal penetration of the host cell walls and subsequent contact with the host plasma membrane, and not a requirement for HR elicitation. O2 - generation in the mesophyll tissue beneath attacked cells was associated with the response mediated by the genes Mla12 and Mlg. However, only BCPMla12 showed mesophyll cell death. The data indicate that, in barley, O2 - accumulation is not a single key determinant of HR in response to a powdery mildew attack.

scholarly journals Feedback Control of the Arabidopsis Hypersensitive Response

2004 ◽  
Vol 17 (4) ◽  
pp. 357-365 ◽  
Author(s):  
Chu Zhang ◽  
Annie Tang Gutsche ◽  
Allan D. Shapiro
Keyword(s):  
Hydrogen Peroxide ◽  
Salicylic Acid ◽  
Pseudomonas Syringae ◽  
Hypersensitive Response ◽  
Ion Leakage ◽  
Wild Type ◽  
Regulatory Circuits ◽  
Acid Accumulation ◽  
Salicylic Acid Accumulation ◽  
Hydrogen Peroxide Accumulation

The plant hypersensitive response (HR) to avirulent bacterial pathogens results from programmed cell death of plant cells in the infected region. Ion leakage and changes in signaling components associated with HR progression were measured. These studies compared Arabidopsis mutants affecting feedback loops with wild-type plants, with timepoints taken hourly. In response to Pseudomonas syringae pv. tomato DC3000·avrB, npr1-2 mutant plants showed increased ion leakage relative to wild-type plants. Hydrogen peroxide accumulation was similar to that in wild type, but salicylic acid accumulation was reduced at some timepoints. With DC3000·avrRpt2, similar trends were seen. In response to DC3000·avrB, ndr1-1 mutant plants showed more ion leakage than wild-type or npr1-2 plants. Hydrogen peroxide accumulation was delayed by approximately 1 h and reached half the level seen with wild-type plants. Salicylic acid accumulation was similar to npr1-2 mutant plants. With DC3000·avrRpt2, ndr1-1 mutant plants showed no ion leakage, no hydrogen peroxide accumulation, and minimal salicylic acid accumulation. Results with a ndr1-1 and npr1-2 double mutant were similar to ndr1-1. A model consistent with these data is presented, in which one positive and two negative regulatory circuits control HR progression. Understanding this circuitry will facilitate HR manipulation for enhanced disease resistance.

scholarly journals Salicylic Acid Accumulation Controlled by LSD1 Is Essential in Triggering Cell Death in Response to Abiotic Stress

Cells ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 962
Author(s):  
Maciej Jerzy Bernacki ◽  
Anna Rusaczonek ◽  
Weronika Czarnocka ◽  
Stanisław Karpiński
Keyword(s):  
Cell Death ◽  
Salicylic Acid ◽  
Abiotic Stress ◽  
Wild Type ◽  
Pr Genes ◽  
Genes Expression ◽  
Salicylic Acid Accumulation ◽  
Cell Death Phenotype ◽  
Insight Into

Salicylic acid (SA) is well known hormonal molecule involved in cell death regulation. In response to a broad range of environmental factors (e.g., high light, UV, pathogens attack), plants accumulate SA, which participates in cell death induction and spread in some foliar cells. LESION SIMULATING DISEASE 1 (LSD1) is one of the best-known cell death regulators in Arabidopsis thaliana. The lsd1 mutant, lacking functional LSD1 protein, accumulates SA and is conditionally susceptible to many biotic and abiotic stresses. In order to get more insight into the role of LSD1-dependent regulation of SA accumulation during cell death, we crossed the lsd1 with the sid2 mutant, caring mutation in ISOCHORISMATE SYNTHASE 1(ICS1) gene and having deregulated SA synthesis, and with plants expressing the bacterial nahG gene and thus decomposing SA to catechol. In response to UV A+B irradiation, the lsd1 mutant exhibited clear cell death phenotype, which was reversed in lsd1/sid2 and lsd1/NahG plants. The expression of PR-genes and the H2O2 content in UV-treated lsd1 were significantly higher when compared with the wild type. In contrast, lsd1/sid2 and lsd1/NahG plants demonstrated comparability with the wild-type level of PR-genes expression and H2O2. Our results demonstrate that SA accumulation is crucial for triggering cell death in lsd1, while the reduction of excessive SA accumulation may lead to a greater tolerance toward abiotic stress.

scholarly journals BAX INHIBITOR-1 Is Required for Full Susceptibility of Barley to Powdery Mildew

2010 ◽  
Vol 23 (9) ◽  
pp. 1217-1227 ◽  
Author(s):  
Ruth Eichmann ◽  
Melanie Bischof ◽  
Corina Weis ◽  
Jane Shaw ◽  
Christophe Lacomme ◽  
...  
Keyword(s):  
Cell Death ◽  
Powdery Mildew ◽  
Gene Silencing ◽  
Defense Responses ◽  
Negative Control ◽  
Cellular Level ◽  
Virus Induced Gene Silencing ◽  
Powdery Mildew Fungus ◽  
Basal Resistance ◽  
Enhanced Resistance

BAX INHIBITOR-1 (BI-1) is one of the few proteins known to have cross-kingdom conserved functions in negative control of programmed cell death. Additionally, barley BI-1 (HvBI-1) suppresses defense responses and basal resistance to the powdery mildew fungus Blumeria graminis f. sp. hordei and enhances resistance to cell death–provoking fungi when overexpressed in barley. Downregulation of HvBI-1 by transient-induced gene silencing or virus-induced gene silencing limited susceptibility to B. graminis f. sp. hordei, suggesting that HvBI-1 is a susceptibility factor toward powdery mildew. Transient silencing of BI-1 did not limit supersusceptibility induced by overexpression of MLO. Transgenic barley plants harboring an HvBI-1 RNA interference (RNAi) construct displayed lower levels of HvBI-1 transcripts and were less susceptible to powdery mildew than wild-type plants. At the cellular level, HvBI-1 RNAi plants had enhanced resistance to penetration by B. graminis f. sp. hordei. These data support a function of BI-1 in modulating cell-wall-associated defense and in establishing full compatibility of B. graminis f. sp. hordei with barley.

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