scholarly journals Arabidopsis thaliana EDS4 Contributes to Salicylic Acid (SA)-Dependent Expression of Defense Responses: Evidence for Inhibition of Jasmonic Acid Signaling by SA

2000 ◽  
Vol 13 (5) ◽  
pp. 503-511 ◽  
Author(s):  
Vaijayanti Gupta ◽  
Michael G. Willits ◽  
Jane Glazebrook

The Arabidopsis enhanced disease susceptibility 4 (eds4) mutation causes enhanced susceptibility to infection by the bacterial pathogen Pseudomonas syringae pv. Maculicola ES4326 (Psm ES4326). Gene-for-gene resistance to bacteria carrying the avirulence gene avrRpt2 is not significantly affected by eds4. Plants homozygous for eds4 exhibit reduced expression of the pathogenesis-related gene PR-1 after infection by Psm ES4326, weakened responses to treatment with the signal molecule salicylic acid (SA), impairment of the systemic acquired resistance response, and reduced accumulation of SA after infection with Psm ES4326. These phenotypes indicate that EDS4 plays a role in SA-dependent signaling. SA has been shown to have a negative effect on activation of gene expression by the signal molecule jasmonic acid (JA). Two mutations that cause reduced SA levels, eds4 and pad4, cause heightened responses to inducers of JA-dependent gene expression, providing genetic evidence to support the idea that SA interferes with JA-dependent signaling. Two possible working models of the role of EDS4 in governing activation of defense responses are presented.

2019 ◽  
Vol 20 (3) ◽  
pp. 671 ◽  
Author(s):  
Ning Li ◽  
Xiao Han ◽  
Dan Feng ◽  
Deyi Yuan ◽  
Li-Jun Huang

During their lifetime, plants encounter numerous biotic and abiotic stresses with diverse modes of attack. Phytohormones, including salicylic acid (SA), ethylene (ET), jasmonate (JA), abscisic acid (ABA), auxin (AUX), brassinosteroid (BR), gibberellic acid (GA), cytokinin (CK) and the recently identified strigolactones (SLs), orchestrate effective defense responses by activating defense gene expression. Genetic analysis of the model plant Arabidopsis thaliana has advanced our understanding of the function of these hormones. The SA- and ET/JA-mediated signaling pathways were thought to be the backbone of plant immune responses against biotic invaders, whereas ABA, auxin, BR, GA, CK and SL were considered to be involved in the plant immune response through modulating the SA-ET/JA signaling pathways. In general, the SA-mediated defense response plays a central role in local and systemic-acquired resistance (SAR) against biotrophic pathogens, such as Pseudomonas syringae, which colonize between the host cells by producing nutrient-absorbing structures while keeping the host alive. The ET/JA-mediated response contributes to the defense against necrotrophic pathogens, such as Botrytis cinerea, which invade and kill hosts to extract their nutrients. Increasing evidence indicates that the SA- and ET/JA-mediated defense response pathways are mutually antagonistic.


2014 ◽  
Vol 20 (1-2) ◽  
Author(s):  
A. Ezzat ◽  
Z. Szabó ◽  
J. Nyéki

Systemic acquired resistance (SAR) is a mechanism of induced defense that confers long-lasting protection against a broad spectrum of microorganisms. Salicylic acid (SA) is the signal molecule which is required for induce SAR and is associated with accumulation of pathogenesis-related proteins, which are thought to contribute to resistance. SA paly vital role in some related resistance gene expression in plant cell which have direct or indirect effect on pathogen growth as SA has direct toxicity for pathogen and in the same time has stimulation effect for some enzyme related to reduce the oxidative burst.


Genetics ◽  
2002 ◽  
Vol 161 (2) ◽  
pp. 803-811
Author(s):  
Gregory J Rairdan ◽  
Terrence P Delaney

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.


2007 ◽  
Vol 97 (7) ◽  
pp. 794-802 ◽  
Author(s):  
Shobha D. Potlakayala ◽  
Darwin W. Reed ◽  
Patrick S. Covello ◽  
Pierre R. Fobert

Systemic acquired resistance (SAR) is an induced defense response that confers long-lasting protection against a broad range of microbial pathogens. Here we show that treatment of Brassica napus plants with the SAR-inducing chemical benzo-(1,2,3)-thiadiazole-7-carbothioic acid S-methyl ester (BTH) significantly enhanced resistance against virulent strains of the bacterial pathogen Pseudomonas syringae pv. maculicola and the fungal pathogen Leptosphaeria maculans. Localized preinoculation of plants with an avirulent strain of P. syringae pv. maculicola also enhanced resistance to these pathogens but was not as effective as BTH treatment. Single applications of either SAR-inducing pretreatment were effective against P. syringae pv. maculicola, even when given more than 3 weeks prior to the secondary challenge. The pretreatments also led to the accumulation of pathogenesis-related (PR) genes, including BnPR-1 and BnPR-2, with higher levels of transcripts observed in the BTH-treatment material. B. napus plants expressing a bacterial salicylate hydroxylase transgene (NahG) that metabolizes salicylic acid to catechol were substantially compromised in SAR and accumulated reduced levels of PR gene transcripts when compared with untransformed controls. Thus, SAR in B. napus displays many of the hallmarks of classical SAR including long lasting and broad host range resistance, association with PR gene activation, and a requirement for salicylic acid.


Plants ◽  
2020 ◽  
Vol 9 (5) ◽  
pp. 624 ◽  
Author(s):  
Vicente Montejano-Ramírez ◽  
Ernesto García-Pineda ◽  
Eduardo Valencia-Cantero

Plants face a variety of biotic and abiotic stresses including attack by microbial phytopathogens and nutrient deficiencies. Some bacterial volatile organic compounds (VOCs) activate defense and iron-deficiency responses in plants. To establish a relationship between defense and iron deficiency through VOCs, we identified key genes in the defense and iron-deprivation responses of the legume model Medicago truncatula and evaluated the effect of the rhizobacterial VOC N,N-dimethylhexadecylamine (DMHDA) on the gene expression in these pathways by RT-qPCR. DMHDA increased M. truncatula growth 1.5-fold under both iron-sufficient and iron-deficient conditions compared with untreated plants, whereas salicylic acid and jasmonic acid decreased growth. Iron-deficiency induced iron uptake and defense gene expression. Moreover, the effect was greater in combination with DMHDA. Salicylic acid, Pseudomonas syringae, jasmonic acid, and Botrytis cinerea had inhibitory effects on growth and iron response gene expression but activated defense genes. Taken together, our results showed that the VOC DMHDA activates defense and iron-deprivation pathways while inducing a growth promoting effect unlike conventional phytohormones, highlighting that DMHDA does not mimic jasmonic acid but induces an alternative pathway. This is a novel aspect in the complex interactions between biotic and abiotic stresses.


2019 ◽  
Vol 20 (11) ◽  
pp. 2849 ◽  
Author(s):  
Songwei Li ◽  
Yijie Dong ◽  
Lin Li ◽  
Yi Zhang ◽  
Xiufen Yang ◽  
...  

Panama disease, or Fusarium wilt, the most serious disease in banana cultivation, is caused by Fusarium oxysporum f. sp. cubense (FOC) and has led to great economic losses worldwide. One effective way to combat this disease is by enhancing host plant resistance. The cerato-platanin protein (CPP) family is a group of small secreted cysteine-rich proteins in filamentous fungi. CPPs as elicitors can trigger the immune system resulting in defense responses in plants. In this study, we characterized a novel cerato-platanin-like protein in the secretome of Fusarium oxysporum f. sp. cubense race 4 (FOC4), named FocCP1. In tobacco, the purified recombinant FocCP1 protein caused accumulation of reactive oxygen species (ROS), formation of necrotic reaction, deposition of callose, expression of defense-related genes, and accumulation of salicylic acid (SA) and jasmonic acid (JA) in tobacco. These results indicated that FocCP1 triggered a hypersensitive response (HR) and systemic acquired resistance (SAR) in tobacco. Furthermore, FocCP1 enhanced resistance tobacco mosaic virus (TMV) disease and Pseudomonas syringae pv. tabaci 6605 (Pst. 6605) infection in tobacco and improved banana seedling resistance to FOC4. All results provide the possibility of further research on immune mechanisms of plant and pathogen interactions, and lay a foundation for a new biological strategy of banana wilt control in the future.


Genetics ◽  
1998 ◽  
Vol 149 (2) ◽  
pp. 537-548
Author(s):  
Sigrid M Volko ◽  
Thomas Boller ◽  
Frederick M Ausubel

Abstract To identify plant defense components that are important in restricting the growth of virulent pathogens, we screened for Arabidopsis mutants in the accession Columbia (carrying the transgene BGL2-GUS) that display enhanced disease susceptibility to the virulent bacterial pathogen Pseudomonas syringae pv. maculicola (Psm) ES4326. Among six (out of a total of 11 isolated) enhanced disease susceptibility (eds) mutants that were studied in detail, we identified one allele of the previously described npr1/nim1/sai1 mutation, which is affected in mounting a systemic acquired resistance response, one allele of the previously identified EDS5 gene, and four EDS genes that have not been previously described. The six eds mutants studied in detail (npr1-4, eds5-2, eds10-1, eds11-1, eds12-1, and eds13-1) displayed different patterns of enhanced susceptibility to a variety of phytopathogenic bacteria and to the obligate biotrophic fungal pathogen Erysiphe orontii, suggesting that particular EDS genes have pathogen-specific roles in conferring resistance. All six eds mutants retained the ability to mount a hypersensitive response and to restrict the growth of the avirulent strain Psm ES4326/avrRpt2. With the exception of npr1-4, the mutants were able to initiate a systemic acquired resistance (SAR) response, although enhanced growth of Psm ES4326 was still detectable in leaves of SAR-induced plants. The data presented here indicate that eds genes define a variety of components involved in limiting pathogen growth, that many additional EDS genes remain to be discovered, and that direct screens for mutants with altered susceptibility to pathogens are helpful in the dissection of complex pathogen response pathways in plants.


Plants ◽  
2020 ◽  
Vol 9 (2) ◽  
pp. 136 ◽  
Author(s):  
Loredana Scalschi ◽  
Eugenio Llorens ◽  
Pilar García-Agustín ◽  
Begonya Vicedo

The jasmonic acid pathway has been considered as the backbone of the response against necrotrophic pathogens. However, a hemi-biotrophic pathogen, such as Pseudomonas syringae, has taken advantage of the crosstalk between the different plant hormones in order to manipulate the responses for its own interest. Despite that, the way in which Pseudomonas syringae releases coronatine to activate jasmonic acid-derived responses and block the activation of salicylic acid-mediated responses is widely known. However, the implication of the jasmonic intermediates in the plant-Pseudomonas interaction is not studied yet. In this work, we analyzed the response of both, plant and bacteria using SiOPR3 tomato plants. Interestingly, SiOPR3 plants are more resistant to infection with Pseudomonas. The gene expression of bacteria showed that, in SiOPR3 plants, the activation of pathogenicity is repressed in comparison to wild type plants, suggesting that the jasmonic acid pathway might play a role in the pathogenicity of the bacteria. Moreover, treatments with JA restore the susceptibility as well as activate the expression of bacterial pathogenicity genes. The observed results suggest that a complete jasmonic acid pathway is necessary for the susceptibility of tomato plants to Pseudomonas syringae.


2012 ◽  
Vol 25 (11) ◽  
pp. 1459-1468 ◽  
Author(s):  
Heather L. Shearer ◽  
Yu Ti Cheng ◽  
Lipu Wang ◽  
Jinman Liu ◽  
Patrick Boyle ◽  
...  

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.


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