The THO/TREX Complex Active in Alternative Splicing Mediates Plant Responses to Salicylic Acid and Jasmonic Acid

Salicylic acid (SA) and jasmonic acid (JA) are essential plant immune hormones, which could induce plant resistance to multiple pathogens. However, whether common components are employed by both SA and JA to induce defense is largely unknown. In this study, we found that the enhanced disease susceptibility 8 (EDS8) mutant was compromised in plant defenses to hemibiotrophic pathogen Pseudomonas syringae pv. maculicola ES4326 and necrotrophic pathogen Botrytis cinerea, and was deficient in plant responses to both SA and JA. The EDS8 was identified to be THO1, which encodes a subunit of the THO/TREX complex, by using mapping-by-sequencing. To check whether the EDS8 itself or the THO/TREX complex mediates SA and JA signaling, the mutant of another subunit of the THO/TREX complex, THO3, was tested. THO3 mutation reduced both SA and JA induced defenses, indicating that the THO/TREX complex is critical for plant responses to these two hormones. We further proved that the THO/TREX interacting protein SERRATE, a factor regulating alternative splicing (AS), was involved in plant responses to SA and JA. Thus, the AS events in the eds8 mutant after SA or JA treatment were determined, and we found that the SA and JA induced different alternative splicing events were majorly modulated by EDS8. In summary, our study proves that the THO/TREX complex active in AS is involved in both SA and JA induced plant defenses.

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Abscisic Acid–Cytokinin Antagonism Modulates Resistance Against Pseudomonas syringae in Tobacco

Phytopathology ◽

10.1094/phyto-03-14-0076-r ◽

2014 ◽

Vol 104 (12) ◽

pp. 1283-1288 ◽

Cited By ~ 16

Author(s):

Dominik K. Großkinsky ◽

Eric van der Graaff ◽

Thomas Roitsch

Keyword(s):

Salicylic Acid ◽

Abscisic Acid ◽

Jasmonic Acid ◽

Induced Resistance ◽

Pseudomonas Syringae ◽

Regulatory Mechanism ◽

Plant Defenses ◽

Plant Immunity ◽

Negative Regulator ◽

Exogenous Application

Phytohormones are known as essential regulators of plant defenses, with ethylene, jasmonic acid, and salicylic acid as the central immunity backbone, while other phytohormones have been demonstrated to interact with this. Only recently, a function of the classic phytohormone cytokinin in plant immunity has been described in Arabidopsis, rice, and tobacco. Although interactions of cytokinins with salicylic acid and auxin have been indicated, the complete network of cytokinin interactions with other immunity-relevant phytohormones is not yet understood. Therefore, we studied the interaction of kinetin and abscisic acid as a negative regulator of plant immunity to modulate resistance in tobacco against Pseudomonas syringae. By analyzing infection symptoms, pathogen proliferation, and accumulation of the phytoalexin scopoletin as a key mediator of kinetin-induced resistance in tobacco, antagonistic interaction of these phytohormones in plant immunity was identified. Kinetin reduced abscisic acid levels in tobacco, while increased abscisic acid levels by exogenous application or inhibition of abscisic acid catabolism by diniconazole neutralized kinetin-induced resistance. Based on these results, we conclude that reduction of abscisic acid levels by enhanced abscisic acid catabolism strongly contributes to cytokinin-mediated resistance effects. Thus, the identified cytokinin–abscisic acid antagonism is a novel regulatory mechanism in plant immunity.

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Ultraviolet radiation enhances salicylic acid-mediated defense signaling and resistance to Pseudomonas syringae DC3000 in a jasmonic acid-deficient tomato mutant

Plant Signaling & Behavior ◽

10.1080/15592324.2019.1581560 ◽

2019 ◽

Vol 14 (4) ◽

pp. e1581560 ◽

Cited By ~ 6

Author(s):

Rocío Escobar Bravo ◽

Gang Chen ◽

Katharina Grosser ◽

Nicole M. Van Dam ◽

Kirsten A. Leiss ◽

...

Keyword(s):

Salicylic Acid ◽

Jasmonic Acid ◽

Ultraviolet Radiation ◽

Pseudomonas Syringae ◽

Defense Signaling ◽

Tomato Mutant

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Chitosan Oligosaccharide Induces Resistance to Pseudomonas syringae pv. tomato DC3000 in Arabidopsis thaliana by Activating Both Salicylic Acid– and Jasmonic Acid–Mediated Pathways

Molecular Plant-Microbe Interactions ◽

10.1094/mpmi-03-18-0071-r ◽

2018 ◽

Vol 31 (12) ◽

pp. 1271-1279 ◽

Cited By ~ 21

Author(s):

Xiaochen Jia ◽

Haihong Zeng ◽

Wenxia Wang ◽

Fuyun Zhang ◽

Heng Yin

Keyword(s):

Salicylic Acid ◽

Jasmonic Acid ◽

Induced Resistance ◽

Pseudomonas Syringae ◽

Plant Immunity ◽

Chitosan Oligosaccharide ◽

Induction Effect ◽

Tomato Dc3000 ◽

Expression Of Genes ◽

Underlying Mechanisms

Chitosan oligosaccharide (COS) is an effective plant immunity elicitor; however, its induction mechanism in plants is complex and needs further investigation. In this study, the Arabidopsis–Pseudomonas syringae pv. tomato DC3000 (hereafter called DC3000) interaction was used to investigate the induction effect and the underlying mechanisms of COS. COS is effective in inducing resistance to DC3000 in Arabidopsis, and our results demonstrate that treatment with COS 3 days before DC3000 inoculation provided the most effective resistance. Disease severity in jar1 (jasmonic acid [JA]-deficient mutant), NahG, and sid2 (salicylic acid [SA]-deficient mutants) suggest both the SA and JA pathways are required for the Arabidopsis response to DC3000. COS pretreatment induced resistance in wild type (WT), jar1, and also, although to a lesser degree, in NahG and sid2 plants, implying that the SA and JA pathways play redundant roles in COS-induced resistance to DC3000. In COS-pretreated plants, expression of genes related to the SA pathway (PR1, PR2, and PR5) and SA content increased in both WT and jar1. Moreover, expression of genes related to the JA pathway (PDF1.2 and VSP2) and JA content both increased in WT and NahG. In conclusion, COS induces resistance to DC3000 in Arabidopsis by activating both SA- and JA-mediated pathways, although SA and JA pathways play redundant roles in this COS-induced resistance.

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Bacterial Compound N,N-Dimethylhexadecylamine Modulates Expression of Iron Deficiency and Defense Response Genes in Medicago truncatula Independently of the Jasmonic Acid Pathway

Plants ◽

10.3390/plants9050624 ◽

2020 ◽

Vol 9 (5) ◽

pp. 624 ◽

Cited By ~ 1

Author(s):

Vicente Montejano-Ramírez ◽

Ernesto García-Pineda ◽

Eduardo Valencia-Cantero

Keyword(s):

Gene Expression ◽

Salicylic Acid ◽

Iron Deficiency ◽

Jasmonic Acid ◽

Pseudomonas Syringae ◽

Medicago Truncatula ◽

Abiotic Stresses ◽

Biotic And Abiotic Stresses ◽

Iron Deprivation ◽

Iron Deficient

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.

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Eliciting Plant Defenses Through Herbivore-Induced Plant Volatiles’ Exposure in Sweet Peppers

Frontiers in Ecology and Evolution ◽

10.3389/fevo.2021.776827 ◽

2022 ◽

Vol 9 ◽

Author(s):

Chaymaa Riahi ◽

Jhonn González-Rodríguez ◽

Miquel Alonso-Valiente ◽

Alberto Urbaneja ◽

Meritxell Pérez-Hedo

Keyword(s):

Salicylic Acid ◽

Jasmonic Acid ◽

Methyl Jasmonate ◽

Plant Volatiles ◽

Methyl Salicylate ◽

Plant Defenses ◽

Sweet Pepper ◽

Induced Plant Volatiles ◽

Herbivore Induced Plant Volatiles ◽

Pepper Plants

Insect herbivory activates plant defense mechanisms and releases a blend of herbivore-induced plant volatiles (HIPVs). These volatile compounds may be involved in plant-plant communication and induce defense response in undamaged plants. In this work, we investigated whether the exposure of sweet pepper plants to HIPVs [(Z)-3-hexenol, (Z)-3-hexenyl acetate, (Z)-3-hexenyl propanoate, (Z)-3-hexenyl butanoate, hexyl butanoate, methyl salicylate and methyl jasmonate] activates the sweet pepper immune defense system. For this, healthy sweet pepper plants were individually exposed to the each of the above mentioned HIPVs over 48 h. The expression of jasmonic acid and salicylic acid related genes was quantified. Here, we show that all the tested volatiles induced plant defenses by upregulating the jasmonic acid and salicylic acid signaling pathway. Additionally, the response of Frankliniella occidentalis, a key sweet pepper pest, and Orius laevigatus, the main natural enemy of F. occidentalis, to HIPV-exposed sweet pepper plants were studied in a Y-tube olfactometer. Only plants exposed to (Z)-3-hexenyl propanoate and methyl salicylate repelled F. occidentalis whereas O. laevigatus showed a strong preference to plants exposed to (Z)-3-hexenol, (Z)-3-hexenyl propanoate, (Z)-3-hexenyl butanoate, methyl salicylate and methyl jasmonate. Our results show that HIPVs act as elicitors to sweet pepper plant defenses by enhancing defensive signaling pathways. We anticipate our results to be a starting point for integrating HIPVs-based approaches in sweet pepper pest management systems which may provide a sustainable strategy to manage insect pests in horticultural plants.

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Role of Jasmonic Acid Pathway in Tomato Plant-Pseudomonas syringae Interaction

Plants ◽

10.3390/plants9020136 ◽

2020 ◽

Vol 9 (2) ◽

pp. 136 ◽

Cited By ~ 1

Author(s):

Loredana Scalschi ◽

Eugenio Llorens ◽

Pilar García-Agustín ◽

Begonya Vicedo

Keyword(s):

Gene Expression ◽

Salicylic Acid ◽

Jasmonic Acid ◽

Pseudomonas Syringae ◽

Tomato Plant ◽

Wild Type ◽

Tomato Plants ◽

Bacterial Pathogenicity ◽

Acid Pathway

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.

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Facilitation of Fusarium graminearum Infection by 9-Lipoxygenases in Arabidopsis and Wheat

Molecular Plant-Microbe Interactions ◽

10.1094/mpmi-04-15-0096-r ◽

2015 ◽

Vol 28 (10) ◽

pp. 1142-1152 ◽

Cited By ~ 28

Author(s):

Vamsi J. Nalam ◽

Syeda Alam ◽

Jantana Keereetaweep ◽

Barney Venables ◽

Dehlia Burdan ◽

...

Keyword(s):

Arabidopsis Thaliana ◽

Salicylic Acid ◽

Disease Resistance ◽

Jasmonic Acid ◽

Fusarium Graminearum ◽

Head Blight ◽

Enhanced Resistance ◽

Susceptibility Factors ◽

Ja Signaling ◽

Important Disease

Fusarium graminearum causes Fusarium head blight, an important disease of wheat. F. graminearum can also cause disease in Arabidopsis thaliana. Here, we show that the Arabidopsis LOX1 and LOX5 genes, which encode 9-lipoxygenases (9-LOXs), are targeted during this interaction to facilitate infection. LOX1 and LOX5 expression were upregulated in F. graminearum–inoculated plants and loss of LOX1 or LOX5 function resulted in enhanced disease resistance in the corresponding mutant plants. The enhanced resistance to F. graminearum infection in the lox1 and lox5 mutants was accompanied by more robust induction of salicylic acid (SA) accumulation and signaling and attenuation of jasmonic acid (JA) signaling in response to infection. The lox1- and lox5-conferred resistance was diminished in plants expressing the SA-degrading salicylate hydroxylase or by the application of methyl-JA. Results presented here suggest that plant 9-LOXs are engaged during infection to control the balance between SA and JA signaling to facilitate infection. Furthermore, since silencing of TaLpx-1 encoding a 9-LOX with homology to LOX1 and LOX5, resulted in enhanced resistance against F. graminearum in wheat, we suggest that 9-LOXs have a conserved role as susceptibility factors in disease caused by this important fungus in Arabidopsis and wheat.

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A Chimeric IDD4 Repressor Constitutively Induces Immunity in Arabidopsis via the Modulation of Salicylic Acid and Jasmonic Acid Homeostasis

Plant and Cell Physiology ◽

10.1093/pcp/pcz057 ◽

2019 ◽

Vol 60 (7) ◽

pp. 1536-1555 ◽

Cited By ~ 7

Author(s):

Ronny Vï¿½lz ◽

Soon-Kap Kim ◽

Jianing Mi ◽

Kiruthiga G Mariappan ◽

Anna Siodmak ◽

...

Keyword(s):

Salicylic Acid ◽

Jasmonic Acid ◽

Pseudomonas Syringae ◽

Plant Immunity ◽

Stress Hormones ◽

Gene Clusters ◽

Binding Studies ◽

Genome Wide ◽

Wide Range ◽

Dna Binding Studies

Abstract INDETERMINATE DOMAIN (IDD)/BIRD proteins belong to a highly conserved plant-specific group of transcription factors with dedicated functions in plant physiology and development. Here, we took advantage of the chimeric repressor gene-silencing technology (CRES-T, SRDX) to widen our view on the role of IDD4/IMPERIAL EAGLE and IDD family members in plant immunity. The hypomorphic idd4SRDX lines are compromised in growth and show a robust autoimmune phenotype. Hormonal measurements revealed the concomitant accumulation of salicylic acid and jasmonic acid suggesting that IDDs are involved in regulating the metabolism of these biotic stress hormones. The analysis of immunity-pathways showed enhanced activation of immune MAP kinase-signaling pathways, the accumulation of hydrogen peroxide and spontaneous programmed cell death. The transcriptome of nonelicited idd4SRDX lines can be aligned to approximately 40% of differentially expressed genes (DEGs) in flg22-treated wild-type plants. The pattern of DEGs implies IDDs as pivotal repressors of flg22-dependent gene induction. Infection experiments showed the increased resistance of idd4SRDX lines to Pseudomonas syringae and Botrytis cinerea implying a function of IDDs in defense adaptation to hemibiotrophs and necrotrophs. Genome-wide IDD4 DNA-binding studies (DAP-SEQ) combined with DEG analysis of idd4SRDX lines identified IDD4-regulated functional gene clusters that contribute to plant growth and development. In summary, we discovered that the expression of idd4SRDX activates a wide range of defense-related traits opening up the possibility to apply idd4SRDX as a powerful tool to stimulate innate immunity in engineered crops.

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

Molecular Plant-Microbe Interactions ◽

10.1094/mpmi.2000.13.5.503 ◽

2000 ◽

Vol 13 (5) ◽

pp. 503-511 ◽

Cited By ~ 114

Author(s):

Vaijayanti Gupta ◽

Michael G. Willits ◽

Jane Glazebrook

Keyword(s):

Gene Expression ◽

Salicylic Acid ◽

Jasmonic Acid ◽

Pseudomonas Syringae ◽

Systemic Acquired Resistance ◽

Acquired Resistance ◽

Defense Responses ◽

Avirulence Gene ◽

Signal Molecule ◽

Resistance Response

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.

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