scholarly journals Characterization of Geminivirus Resistance in an Accession of Capsicum chinense Jacq.

2011 ◽  
Vol 24 (2) ◽  
pp. 172-182 ◽  
Author(s):  
Marco A. García-Neria ◽  
Rafael F. Rivera-Bustamante
Keyword(s):  
Systemic Acquired Resistance ◽  
Acquired Resistance ◽  
Resistance Breeding ◽  
Marker Genes ◽  
Oxygen Species ◽  
Breeding Programs ◽  
Viral Movement ◽  
Resistance Trait ◽  
Defensive Mechanism

Pepper golden mosaic virus (PepGMV) and Pepper huasteco yellow vein virus (PHYVV), members of the Geminiviridae family, are important pathogens of pepper (Capsicum annuum L.) and other solanaceous crops. Accession BG-3821 of C. chinense Jacq. was reported earlier as resistant to mixed infection with PepGMV and PHYVV. In this work, we characterized the Geminivirus resistance trait present in BG-3821. Segregation analysis suggested that resistance depends on two genes. Our data showed that PepGMV replication in protoplast of resistant plants is approximately 70% lower when compared with the levels observed in protoplasts from susceptible plants. Additionally, viral movement is less efficient in resistant plants. We also evaluated several characteristics commonly associated with systemic acquired resistance (SAR), which is a conserved defensive mechanism. The concentration of salicylic acid was higher in resistant plants inoculated with PepGMV than in susceptible plants. Marker genes for SAR were induced after inoculation with PepGMV in resistant leaves. Similarly, we found a higher accumulation of reactive oxygen species on resistant leaves compared with susceptible ones. A model for the mechanism acting in the Geminivirus resistance detected in BG-3821 is proposed. Finally, the importance of BG-3821 in Geminivirus resistance breeding programs is discussed.

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.

The roles of methyl jasmonate to stress in plants

2019 ◽  
Vol 46 (3) ◽  
pp. 197 ◽  
Author(s):  
Xiaxia Yu ◽  
Wenjin Zhang ◽  
Yu Zhang ◽  
Xiaojia Zhang ◽  
Duoyong Lang ◽  
...  
Keyword(s):  
Methyl Jasmonate ◽  
Systemic Acquired Resistance ◽  
Acquired Resistance ◽  
Heavy Metal Stress ◽  
Antioxidant Systems ◽  
Endogenous Hormones ◽  
Oxygen Species ◽  
Physiological And Biochemical Characteristics ◽  
Pathogenesis Related ◽  
Physiological And Biochemical

Plants are constantly exposed to various stresses, which can degrade their health. The stresses can be alleviated by the application of methyl jasmonate (MeJA), which is a hormone involved in plant signalling. MeJA induces synthesis of defensive compounds and initiates the expression of pathogenesis-related genes involved in systemic acquired resistance and local resistance. Thus, MeJA may be used against pathogens, salt stress, drought stress, low temperature, heavy metal stress and toxicities of other elements. The application of MeJA improves growth, induces the accumulation of active compounds, and affects endogenous hormones levels, and other physiological and biochemical characteristics in stressed plants. Furthermore, MeJA antagonises the adverse effects of osmotic stress by regulating inorganic penetrating ions or organic penetrants to suppress the absorption of toxic ions. MeJA also mitigates oxidative stress by activating antioxidant systems to scavenge reactive oxygen species (ROS) in stressed plants. For these reasons, we reviewed the use of exogenous MeJA in alleviating biotic (pathogens and insects) and abiotic stresses in plants.

scholarly journals Overexpression of a Rice NPR1 Homolog Leads to Constitutive Activation of Defense Response and Hypersensitivity to Light

2005 ◽  
Vol 18 (6) ◽  
pp. 511-520 ◽  
Author(s):  
Mawsheng Chern ◽  
Heather A. Fitzgerald ◽  
Patrick E. Canlas ◽  
Duroy A. Navarre ◽  
Pamela C. Ronald
Keyword(s):  
Systemic Acquired Resistance ◽  
Environmental Changes ◽  
Acquired Resistance ◽  
Northern Analysis ◽  
Wild Type ◽  
Defense Genes ◽  
Isolation And Characterization ◽  
Broad Spectrum Resistance ◽  
Resistance Pathway

Arabidopsis NPR1/NIM1 is a key regulator of systemic acquired resistance (SAR), which confers lasting broad-spectrum resistance. Previous reports indicate that rice has a disease-resistance pathway similar to the Arabidopsis SAR pathway. Here we report the isolation and characterization of a rice NPR1 homologue (NH1). Transgenic rice plants overexpressing NH1 (NH1ox) acquire high levels of resistance to Xanthomonas oryzae pv. oryzae. The resistance phenotype is heritable and correlates with the presence of the transgene and reduced bacterial growth. Northern analysis shows that NH1ox rice spontaneously activates defense genes, contrasting with NPR1-overexpressing Arabidopsis, where defense genes are not activated until induction. Wild-type NH1, but not a point mutant corresponding to npr1-1, interacts strongly with the rice transcription factor rTGA2.2 in yeast two-hybrid. Greenhouse-grown NH1ox plants develop lesion-mimic spots on leaves at preflowering stage although no other developmental effects are observed. However, when grown in growth chambers (GCs) under low light, NH1ox plants are dwarfed, indicating elevated sensitivity to light. The GC-grown NH1ox plants show much higher salicylic acid (SA) levels than the wild type, whereas greenhouse-grown NH1ox plants contain lower SA. These results indicate that NH1 may be involved in the regulation of SA in response to environmental changes.

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.

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

scholarly journals Foliar Spray of Validamycin A or Validoxylamine A Controls Tomato Fusarium Wilt

2005 ◽  
Vol 95 (10) ◽  
pp. 1209-1216 ◽  
Author(s):  
Ryo Ishikawa ◽  
Kentaro Shirouzu ◽  
Hideo Nakashita ◽  
Han-Young Lee ◽  
Takayuki Motoyama ◽  
...  
Keyword(s):  
Systemic Acquired Resistance ◽  
Control Method ◽  
Foliar Application ◽  
Acquired Resistance ◽  
Foliar Spray ◽  
Marker Genes ◽  
Pr Genes ◽  
Validamycin A ◽  
Soil Fumigants

Tomato wilt, caused by the soilborne fungus Fusarium oxysporum f. sp. lycopersici, is effectively controlled by a foliar spray of validamycin A (VMA) or validoxylamine A (VAA) (≥10 μg/ml); however, neither VMA nor VAA is antifungal in vitro. In pot tests, the effect of a foliar application of VMA or VAA at 100 μg/ml lasted for 64 days. Plants sprayed with VMA or VAA accumulated salicylic acid and had elevated expression of the systemic acquired resistance (SAR) marker genes P4 (PR-1), Tag (PR-2), and NP24 (PR-5). Foliar spray of VMA also controlled late blight and powdery mildew of tomato. The disease control by VMA and VAA lasted up to 64 days after treatment, was broad spectrum, and induced the expression of PR genes, all essential indicators of SAR, suggesting that VMA and VAA are plant activators. The foliar application of plant activators is a novel control method for soilborne diseases and may provide an economically feasible alternative to soil fumigants such as methyl bromide.

scholarly journals Disclosure of salicylic acid and jasmonic acid-responsive genes provides a molecular tool for deciphering stress responses in soybean

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Sebastian F. Beyer ◽  
Paloma Sánchez Bel ◽  
Victor Flors ◽  
Holger Schultheiss ◽  
Uwe Conrath ◽  
...  
Keyword(s):  
Salicylic Acid ◽  
Jasmonic Acid ◽  
Stress Responses ◽  
Systemic Acquired Resistance ◽  
Marker Gene ◽  
Acquired Resistance ◽  
Wound Response ◽  
Marker Genes ◽  
Biotrophic Pathogens ◽  
Gene Transcripts

AbstractHormones orchestrate the physiology of organisms. Measuring the activity of defense hormone-responsive genes can help understanding immune signaling and facilitate breeding for plant health. However, different from model species like Arabidopsis, genes that respond to defense hormones salicylic acid (SA) and jasmonic acid (JA) have not been disclosed in the soybean crop. We performed global transcriptome analyses to fill this knowledge gap. Upon exogenous application, endogenous levels of SA and JA increased in leaves. SA predominantly activated genes linked to systemic acquired resistance and defense signaling whereas JA mainly activated wound response-associated genes. In general, SA-responsive genes were activated earlier than those responding to JA. Consistent with the paradigm of biotrophic pathogens predominantly activating SA responses, free SA and here identified most robust SA marker genes GmNIMIN1, GmNIMIN1.2 and GmWRK40 were induced upon inoculation with Phakopsora pachyrhizi, whereas JA marker genes did not respond to infection with the biotrophic fungus. Spodoptera exigua larvae caused a strong accumulation of JA-Ile and JA-specific mRNA transcripts of GmBPI1, GmKTI1 and GmAAT whereas neither free SA nor SA-marker gene transcripts accumulated upon insect feeding. Our study provides molecular tools for monitoring the dynamic accumulation of SA and JA, e.g. in a given stress condition.

scholarly journals Calcium-dependent protein kinase 5 links calcium-signaling with SARD1-dependent immune memory in systemic acquired resistance

2019 ◽  
Author(s):  
Tiziana Guerra ◽  
Silke Schilling ◽  
Fabian-Philipp Sylvester ◽  
Benjamin Conrads ◽  
Tina Romeis
Keyword(s):  
Protein Kinase ◽  
Systemic Acquired Resistance ◽  
Acquired Resistance ◽  
Marker Genes ◽  
List Type ◽  
Dependent Protein Kinase ◽  
Basal Resistance ◽  
Calcium Dependent ◽  
Dependent Protein ◽  
Calcium Dependent Protein Kinase

Summary- Systemic acquired resistance (SAR) prepares infected plants for faster and stronger defense activation upon subsequent attacks. SAR requires an information relay from primary infection to distal tissue and the initiation and maintenance of a self-maintaining phytohormone salicylic acid (SA)-defense loop.- In spatial and temporal resolution we show that calcium-dependent protein kinase CPK5 contributes to immunity and SAR. In local basal resistance CPK5 functions upstream of SA-synthesis, -perception, and -signaling. In systemic tissue, enhanced CPK5 signaling leads to an accumulation of SAR marker genes including transcription factor Systemic Acquired Resistance Deficient 1 (SARD1).- Plants of enhanced CPK5-, but not CPK6-, signaling display a ‘super-priming’ phenotype of enhanced resistance toward a secondary bacterial infection. In sard1 background, CPK5-mediated basal resistance is still mounted but systemic ‘super-priming’ is lost.- The biochemical analysis determines CPK5 half maximal kinase activity for calcium K50 [Ca2+] to ∼100 nM close to the cytoplasmic resting level. This low activation threshold uniquely qualifies CPK5 to decode subtle changes in calcium prerequisite to immune signal relay and to onset and maintenance of priming at later time points in distal tissue. Our data explain why CPK5 functions as a hub in basal and systemic plant immunity.

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