scholarly journals Elicitin Genes Expressed In Vitro by Certain Tobacco Isolates of Phytophthora parasitica Are Down Regulated During Compatible Interactions

2001 ◽  
Vol 14 (3) ◽  
pp. 326-335 ◽  
Author(s):  
Virginie Colas ◽  
Sandrine Conrod ◽  
Paul Venard ◽  
Harald Keller ◽  
Pierre Ricci ◽  
...  
Keyword(s):  
Hypersensitive Response ◽  
Systemic Acquired Resistance ◽  
Acquired Resistance ◽  
Compatible Interaction ◽  
Phytophthora Parasitica ◽  
In Planta ◽  
Black Shank ◽  
Phytophthora Spp ◽  
Compatible Interactions

Phytophthora spp. secrete proteins called elicitins in vitro that can specifically induce hypersensitive response and systemic acquired resistance in tobacco. In Phytophthora parasitica, the causal agent of black shank, most isolates virulent on tobacco are unable to produce elicitins in vitro. Recently, however, a few elicitin-producing P. parasitica strains virulent on tobacco have been isolated. We investigated the potential diversity of elicitin genes in P. parasitica isolates belonging to different genotypes and with various virulence levels toward tobacco as well as elicitin expression pattern in vitro and in planta. Although elicitins are encoded by a multigene family, parA1 is the main elicitin gene expressed. This gene is highly conserved among isolates, regardless of the elicitin production and virulence levels toward tobacco. Moreover, we show that elicitin-producing P. parasitica isolates virulent on tobacco down regulate parA1 expression during compatible interactions, whichever host plant is tested. Conversely, one elicitin-producing P. parasitica isolate that is pathogenic on tomato and avirulent on tobacco still expresses parA1 in the compatible interaction. Therefore, some P. parasitica isolates may evade tobacco recognition by down regulating parA1 in planta. The in planta down regulation of parA1 may constitute a suitable mechanism for P. parasitica to infect tobacco without deleterious consequences for the pathogen.

Characterization of a cell-surface antigen isolated from the plant pathogen Phytophthora parasitica var. nicotianae

1995 ◽  
Vol 73 (S1) ◽  
pp. 1104-1108 ◽  
Author(s):  
N. Séjalon ◽  
R. Dargent ◽  
F. Villalba ◽  
A. Bottin ◽  
M. Rickauer ◽  
...  
Keyword(s):  
Cell Wall ◽  
Synthetic Medium ◽  
Immunogold Labelling ◽  
Phytophthora Parasitica ◽  
In Planta ◽  
Black Shank ◽  
A Cell ◽  
Defence Responses

The genus Phytophthora contains several species that are pathogenic to plants. Phytophthora parasitica var. nicotianae is the causal agent of the black shank disease of tobacco. From this fungus we have isolated and purified to homogeneity a 34-kDa glycoprotein (GP34) that elicits defence responses in tobacco. Among other features, this glycoprotein contains the rare amino acid hydroxyproline. Antibodies against GP34 permitted us to study its localization in vitro and in planta. Ultrastructural cytochemistry using immunogold labelling shows that GP34 is present in the cell wall into which it is secreted by vesicles when the fungus is grown on synthetic medium. In zoospores, labelling precedes and is strictly associated with the formation of a new cell wall. At early stages of infection of tobacco, only a faint labelling of the mycelium is observed. Later on it is enhanced in the incompatible interaction between the fungus and a resistant host cultivar. Key words: cell wall, elicitor, hydroxyproline, Phytophthora, tobacco.

scholarly journals The Arabidopsis NSL2 negatively controls systemic acquired resistance via hypersensitive response

2011 ◽  
Vol 28 (1) ◽  
pp. 9-15 ◽  
Author(s):  
Yutaka Asada ◽  
Masako Yamamoto ◽  
Tomokazu Tsutsui ◽  
Junji Yamaguchi
Keyword(s):  
Hypersensitive Response ◽  
Systemic Acquired Resistance ◽  
Acquired Resistance

scholarly journals Comparative Efficacy of Systemic Acquired Resistance-Inducing Compounds Against Rust Infection in Sunflower Plants

2007 ◽  
Vol 97 (2) ◽  
pp. 179-186 ◽  
Author(s):  
Esther Amzalek ◽  
Yigal Cohen
Keyword(s):  
Systemic Acquired Resistance ◽  
Acquired Resistance ◽  
Foliar Spray ◽  
Racemic Mixture ◽  
In Planta ◽  
Butanoic Acid ◽  
Defense Compounds ◽  
Rust Infection ◽  
Puccinia Helianthi ◽  
Full Protection

Four inducers of systemic acquired resistance (SAR) were examined for their efficacy in controlling rust infection caused by Puccinia helianthi in sunflower plants. Of the four compounds, DL-3-amino-n-butanoic acid (DL-β-aminobutyric acid [BABA]) was the most effective and sodium salicylate (NaSA) was the least effective in protecting against rust. In leaf disk assays, full protection was obtained with BABA at 25 μg/ml, benzodiathiazol-S-methyl ester (BTH) at 100 μg/ml, 2,6-di-chloroisonicotinic acid (INA) at 100 μg/ml, and NaSA at >200 μg/ml. L-2-amino-n-butanoic acid (AABA) was partially effective, whereas N-methyl-BABA and 4-aminobutnoic acid (GABA) were ineffective. The R-enantiomer of BABA, but not the S-enantiomer, was more effective than the racemic mixture. In intact plants, BABA applied as a foliar spray or a root dip, before or after (up to 48 h) inoculation, provided significant protection for 8 days. BTH, INA, and NaSA were less protective and more phytotoxic compared with BABA. BABA did not affect urediospore germination, germ tube growth, appressorial formation, or initial ingress of P. helianthi, but strongly suppressed mycelial colonization in the mesophyll and, consequently, pustule and urediospore formation. No accumulation of defense compounds (phenolics, lignin, or callose) was detected in BABA-treated inoculated or noninoculated plants. This is the first report on the activity of BABA against an obligate Basidomycete pathogen in planta.

scholarly journals N-hydroxy-pipecolic acid is a mobile signal that induces systemic disease resistance in Arabidopsis

2018 ◽  
Author(s):  
Yun Chu Chen ◽  
Eric C. Holmes ◽  
Jakub Rajniak ◽  
Jung-Gun Kim ◽  
Sandy Tang ◽  
...  
Keyword(s):  
Disease Resistance ◽  
Systemic Acquired Resistance ◽  
Systemic Disease ◽  
Acquired Resistance ◽  
Bacterial Pathogen ◽  
Pipecolic Acid ◽  
In Planta ◽  
Global Response ◽  
Promising Target ◽  
Pathogenesis Related

AbstractSystemic acquired resistance (SAR) is a global response in plants induced at the site of infection that leads to long-lasting and broad-spectrum disease resistance at distal, uninfected tissues. Despite the importance of this priming mechanism, the identity of the mobile defense signal that moves systemically throughout plants to initiate SAR has remained elusive. In this paper, we describe a new metabolite, N-hydroxy-pipecolic acid (N-OH-Pip), and provide evidence that this molecule is a mobile signal that plays a central role in initiating SAR signal transduction in Arabidopsis thaliana. We demonstrate that FLAVIN-DEPENDENT MONOOXYGENASE 1 (FMO1), a key regulator of SAR-associated defense priming, can synthesize N-OH-Pip from pipecolic acid in planta, and exogenously applied N-OH-PIP moves systemically in Arabidopsis and can rescue the SAR-deficiency of fmo1 mutants. We also demonstrate that N-OH-Pip treatment causes systemic changes in the expression of pathogenesis-related genes and metabolic pathways throughout the plant, and enhances resistance to a bacterial pathogen. This work provides new insight into the chemical nature of a mobile signal for SAR and also suggests that the N-OH-Pip pathway is a promising target for metabolic engineering to enhance disease resistance.

scholarly journals Conservation of N-hydroxy-pipecolic acid-mediated systemic acquired resistance in crop plants

2019 ◽  
Author(s):  
Eric C. Holmes ◽  
Yun-Chu Chen ◽  
Elizabeth Sattely ◽  
Mary Beth Mudgett
Keyword(s):  
Systemic Acquired Resistance ◽  
Acquired Resistance ◽  
Signal Propagation ◽  
Crop Plants ◽  
Pipecolic Acid ◽  
List Type ◽  
In Planta ◽  
Long Distance ◽  
Plant Kingdom ◽  
Promising Strategy

SUMMARYSignal propagation and the coordination of whole-organism responses in plants rely heavily on small molecules. Systemic acquired resistance (SAR) is one such process in which long-distance signaling activates immune responses in uninfected tissue as a way to limit the spread of a primary, localized infection. Recently, N-hydroxy pipecolic acid (NHP) was discovered and shown to coordinate SAR in Arabidopsis. Here, we provide metabolic and biochemical evidence that NHP is conserved across the plant kingdom and demonstrate a role for NHP in mediating SAR responses in tomato and pepper. We reconstituted the NHP biosynthetic pathway in planta and show that transient expression of two NHP biosynthetic genes in tomato induces enhanced resistance to a bacterial pathogen in distal tissue. Our results suggest engineering strategies to induce NHP-mediated SAR are a promising route to improve broad-spectrum pathogen resistance in crops.IN BRIEFEngineering NHP production is a promising strategy to enhance disease resistance in crops.HIGHLIGHTSArabidopsis N-hydroxy-pipecolic acid (NHP) pathway is conserved across the plant kingdomApplication of NHP to tomato and pepper plants induces a robust SAR responseMetabolic engineering of the Arabidopsis NHP pathway in Solanum lycopersicum leads to enhanced NHP production and defense primingGenetic engineering for enhanced NHP production is a promising strategy to protect crop plants from multiple pathogens

scholarly journals A Single Effector Protein, AvrRpt2EA, from Erwinia amylovora Can Cause Fire Blight Disease Symptoms and Induces a Salicylic Acid–Dependent Defense Response

2018 ◽  
Vol 31 (11) ◽  
pp. 1179-1191 ◽  
Author(s):  
Susan Schröpfer ◽  
Christoph Böttcher ◽  
Thomas Wöhner ◽  
Klaus Richter ◽  
John Norelli ◽  
...  
Keyword(s):  
Salicylic Acid ◽  
Fire Blight ◽  
Systemic Acquired Resistance ◽  
Erwinia Amylovora ◽  
Acquired Resistance ◽  
Inducible Promoter ◽  
Marker Genes ◽  
Effector Protein ◽  
In Planta ◽  
Natural Fire

The AvrRpt2EA effector protein of Erwinia amylovora is important for pathogen recognition in the fire blight–resistant crabapple Malus × robusta 5; however, little is known about its role in susceptible apples. To study its function in planta, we expressed a plant-optimized version of AvrRpt2EA driven by a heat shock–inducible promoter in transgenic plants of the fire blight–susceptible cultivar Pinova. After induced expression of AvrRpt2EA, transgenic lines showed shoot necrosis and browning of older leaves, with symptoms similar to natural fire blight infections. Transgenic expression of this effector protein resulted in an increase in the expression of the salicylic acid (SA)-responsive PR-1 gene but, also, in the levels of SA and its derivatives, with diverse kinetics in leaves of different ages. In contrast, no increase of expression levels of VSP2 paralogs, used as marker genes for the activation of the jasmonic acid (JA)-dependent defense pathway, could be detected, which is in agreement with metabolic profiling of JA and its derivatives. Our work demonstrates that AvrRpt2EA acts as a virulence factor and induces the formation of SA and SA-dependent systemic acquired resistance.

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