scholarly journals Restoration of Defective Cross Talk in ssi2 Mutants: Role of Salicylic Acid, Jasmonic Acid, and Fatty Acids in SSI2-Mediated Signaling

2003 ◽  
Vol 16 (11) ◽  
pp. 1022-1029 ◽  
Author(s):  
Pradeep Kachroo ◽  
Aardra Kachroo ◽  
Ludmila Lapchyk ◽  
David Hildebrand ◽  
Daniel F. Klessig
Keyword(s):  
Cell Death ◽  
Salicylic Acid ◽  
Jasmonic Acid ◽  
Cross Talk ◽  
Pr Genes ◽  
Exogenous Application ◽  
Basal Level Expression ◽  
Sa Signaling ◽  
Spontaneous Cell Death

The Arabidopsis mutants ssi2 and fab2 are defective in stearoyl ACP desaturase, which causes altered salicylic acid (SA)- and jasmonic acid (JA)-mediated defense signaling. Both ssi2 and fab2 plants show spontaneous cell death, express PR genes constitutively, accumulate high levels of SA, and exhibit enhanced resistance to bacterial and oomycete pathogens. In contrast to constitutive activation of the SA pathway, ssi2 and fab2 plants are repressed in JA-mediated induction of the PDF1.2 gene, which suggests that the SSI2-mediated signaling pathway modulates cross talk between the SA and JA pathways. In this study, we have characterized two recessive nonallelic mutants in the ssi2 background, designated as rdc (restorer of defective cross talk) 2 and rdc8. Both ssi2 rdc mutants are suppressed in constitutive SA signaling, show basal level expression of PR-1 gene, and induce high levels of PDF1.2 in response to exogenous application of JA. Interestingly, while the rdc8 mutation completely abolishes spontaneous cell death in ssi2 rdc8 plants, the ssi2 rdc2 plants continue to show some albeit reduced cell death. Fatty acid (FA) analysis showed a reduction in 16:3 levels in ssi2 rdc8 plants, which suggests that this mutation may limit the flux of FAs into the pro-karyotic pathway of glycerolipid biosynthesis. Both rdc2 and rdc8 continue to accumulate high levels of 18:0, which suggests that 18:0 levels were responsible for neither constitutive SA signaling nor repression of JA-induced expression of the PDF1.2 gene in ssi2 plants. We also analyzed SA and JA responses of the fab2-derived shs1 mutant, which accumulates levels of 18:0 over 50% lower than those in the fab2 plants. Even though fab2 shs1 plants were morphologically bigger than fab2 plants, they expressed PR genes constitutively, showed HR-like cell death, and accumulated elevated levels of SA. However, unlike the ssi2 rdc plants, fab2 shs1 plants were unable to induce high levels of PDF1.2 expression in response to exogenous application of JA. Together, these results show that defective cross talk in ssi2 can be restored by second site mutations and is independent of morphological size of the plants, cell death, and elevated levels of 18:0.

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 Ozone Sensitivity in Hybrid Poplar Correlates with Insensitivity to Both Salicylic Acid and Jasmonic Acid. The Role of Programmed Cell Death in Lesion Formation

2000 ◽  
Vol 123 (2) ◽  
pp. 487-496 ◽  
Author(s):  
Jennifer Riehl Koch ◽  
Robert A. Creelman ◽  
Steven M. Eshita ◽  
Mirjana Seskar ◽  
John E. Mullet ◽  
...  
Keyword(s):  
Cell Death ◽  
Salicylic Acid ◽  
Programmed Cell Death ◽  
Jasmonic Acid ◽  
Hybrid Poplar ◽  
Lesion Formation ◽  
Ozone Sensitivity

scholarly journals Weights in the Balance: Jasmonic Acid and Salicylic Acid Signaling in Root-Biotroph Interactions

2009 ◽  
Vol 22 (7) ◽  
pp. 763-772 ◽  
Author(s):  
Caroline Gutjahr ◽  
Uta Paszkowski
Keyword(s):  
Salicylic Acid ◽  
Jasmonic Acid ◽  
Induced Defense ◽  
Arbuscular Mycorrhizal ◽  
Signaling Molecules ◽  
Plant Interactions ◽  
Plant Parts ◽  
Root Interactions ◽  
Sa Signaling

Work on the interaction of aerial plant parts with pathogens has identified the signaling molecules jasmonic acid (JA) and salicylic acid (SA) as important players in induced defense of the plant against invading organisms. Much less is known about the role of JA and SA signaling in root infection. Recent progress has been made in research on plant interactions with biotrophic mutualists and parasites that exclusively associate with roots, namely arbuscular mycorrhizal and rhizobial symbioses on one hand and nematode and parasitic plant interactions on the other hand. Here, we review these recent advances relating JA and SA signaling to specific stages of root colonization and discuss how both signaling molecules contribute to a balance between compatibility and defense in mutualistic as well as parasitic biotroph-root interactions.

Rice-Barnyard Grass Allelopathic Interaction: A Role of Jasmonic Acid and Salicylic Acid

2010 ◽  
Vol 113-116 ◽  
pp. 1782-1786 ◽  
Author(s):  
L.X. You ◽  
P. Wang
Keyword(s):  
Salicylic Acid ◽  
Jasmonic Acid ◽  
Pearson Correlation ◽  
Signal Molecules ◽  
Rice Varieties ◽  
Barnyard Grass ◽  
Future Studies ◽  
Opposite Trend ◽  
Allelopathic Interaction

Exogenous jasmonic acid (JA) and salicylic acid (SA) can have an important effect on rice allelopathy. Currently, the role of endogenous JA and SA on rice-barnyard grass interaction is largely unknown. In this study, the levels of JA and SA in tissues and their correlation to rice allelochemicals inducing with barnyard grass are analyzed. Rice allelochemicals production was enhanced by coexistence with barnyard grass and allelochemicals of the allelopathic variety, PI312777 were generally higher than those of non-allelopathic variety, Liaojing9. Furthermore, JA contents of two rice varieties were generally greater in roots than in shoots, and differed clearly with tested times. The SA levels of PI312777 were generally higher than those of Liaojing9 in shoots but opposite trend in roots. The contents of total allelochemicals correlated positively with SA (Pearson correlation, r = 0.91, P < 0.001). These results indicate that as the phytohormones, JA and SA play a provable role in chemical communication between rice and barnyard grass and participate in rice-barnyard grass allelopathic interaction. Future studies should determine the signal molecules in root exudates of barnyard grass and their functions.

Functional Defects In Neutrophils Derived From Ezh2 Null Mice

Blood ◽  
2013 ◽  
Vol 122 (21) ◽  
pp. 1556-1556
Author(s):  
Albert Perez-Ladaga ◽  
Bennett Caughey ◽  
Huafeng Xie ◽  
Stuart H. Orkin ◽  
David B. Sykes ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Cell Death ◽  
Progenitor Cells ◽  
Board Of Directors ◽  
Cell Lines ◽  
Resting Cells ◽  
Surface Markers ◽  
Advisory Committees ◽  
Spontaneous Cell Death

Abstract Introduction We investigate the role of Ezh2 in neutrophil function using murine progenitor cells differentiated into neutrophils lacking the Ezh2 gene. Ezh2 is the catalytic component of the polycomb repressive complex 2, which methylates lysine 27 of histone H3. It is frequently disrupted in myelodysplastic syndromes (MDS) leading to loss of function (Ernst et al., 2010). Mutations in EZH2 are found in 6% of MDS patients and while not strongly linked to cytopenias or blast proportion, they are independently associated with worse overall survival compared to patients with wildtype EZH2 (Bejar R. et al., 2011 and 2012). We hypothesize that Ezh2 mutations may cause qualitative defects in myeloid cells that impact their function and could contribute to the adverse prognosis observed in EZH2 mutant MDS. Methods Bone marrow from Ezh2 null (Ezh2-/-) and littermate control mice (WT) were transduced with HOXB8 fused to the estrogen receptor ligand-binding domain to produce immortalized myeloid progenitor cells. Removal of estrogen from the media allows these cells differentiate into mature neutrophils (Wang G.G., 2006). Differentiated cells were characterized for surface markers by flow cytometry and for gene expression by PCR of mRNA. Spontaneous cell death was measured by annexin/PI staining. Cell cycle patterns were determined by measuring the red emission of PI. Chemotactic function was assessed by counting cells that migrated across a transwell in presence/absence of the attractant zymosan. For phagocytosis experiments, cells were incubated with Fluoresbrite YG carboxylate beads at 37°C or 4°C. Reactive oxygen species (ROS) generation was measured by the oxidation of dihydrorhodamine 123 into fluorescent rhodamine 123. Results Estrogen withdrawal caused differentiation of both WT and Ezh2-/- lines into cells with mature neutrophil morphology after six days (Figure 1a). Both differentiated lines expressed the neutrophil surface markers CD11b and CD62L and the neutrophil-specific genes lactoferrin and Itgb2l. Ezh2 -/- cells had an increased rate of spontaneous cell death compared to WT in undifferentiated (32.81% vs. 20.33%) and mature cells (32.82% vs. 14.23%). Nevertheless, both progenitor cell lines showed similar cell cycle patterns, demonstrating that Ezh2 absence had no other effect on cell cycle progression. Ezh2 -/- neutrophils failed to migrate towards zymosan (Figure 1b). Expression of Tlr2, which binds zymosan, and other Toll-like receptors (Tlr4/5/9) were similar between the differentiated cell lines. Cells incubated with FITC-zymosan at 37°C showed no fluorescence differences between cell lines, indicating similar adherence. Experiments with neutrophils from an MDS patient with homozygous EZH2 mutations demonstrated a similar migration defect. Additional studies in MDS patient samples are ongoing and will be presented. Phagocytosis was reduced in Ezh2-/-cells. Unstimulated, the number of cells ingesting and adhering YG-beads was significantly greater with WT cells than with Ezh2-/-cells. When activated with fMLP, both lines showed increased adherence of YG-beads but the number of phagocytosing Ezh2-/- cells was reduced. The average number of beads ingested by each cell was lower for Ezh2-/- cells compared to WT (5.95 vs 2.94, p < 0.001) in resting cells, and 9.47 vs. 3.73 in fMLP-activated cells, p < 0.01. The fraction of Ezh2-/- neutrophils generating ROS when stimulated with PMA is 2.4-fold higher than for WT cells. ROS production was greatly reduced in the presence of diphenyleneiodonium (DPI), confirming the role of NADPH oxidase in the generation of ROS. Conclusion Our results indicate impaired function of neutrophils derived from Ezh2-/- mice, demonstrating increased spontaneous cell death, impaired migration, decreased phagocytosis, and overproduction of ROS. Qualitative defects observed in neutrophils deficient for EZH2 may help explain the adverse prognosis associated with these mutations in MDS patients. Disclosures: Bejar: Genoptix: Consultancy, Honoraria, Membership on an entity’s Board of Directors or advisory committees; Celgene: Consultancy, Membership on an entity’s Board of Directors or advisory committees.

scholarly journals Impact of Exogenous Application of Salicylic Acid and Hydrogen Peroxide on Essential Nutrients and Silymarin in Silybum Marianum (L.) Gaertn Grown at Two Different Altitudes of Balochistan Under Cadmium Stress

2021 ◽  
Author(s):  
Mereen Nizar ◽  
Kanval Shaukat ◽  
Noreen Zahra ◽  
Abdul Samad ◽  
Mohammad Bilal Hafeez ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Salicylic Acid ◽  
Cadmium Toxicity ◽  
Foliar Spray ◽  
Cadmium Stress ◽  
Milk Thistle ◽  
Silybum Marianum ◽  
Essential Nutrients ◽  
Exogenous Application

Abstract Cadmium (Cd+2) is a potentially toxic element that inhibits growth and development of several species of plants along with Silybum marianum (L.) Gaertn which is an essential medicinal plant belonging to family Asteraceae. The exogenous application with 0.25µM Salicylic acid (SA) and 10µM hydrogen peroxide (H2O2) to ameliorate harmful effects of cadmium (500 µM) on milk thistle were studied that were grown at two different ecological zones of Balochistan province of Pakistan i.e. Quetta (Qta) and Turbat (Tbt). The design of experiment was Randomized Complete Block Design (RCBD) with three replicates. Application of SA and H2O2, priming (P), Foliar spray (FS) and combinational treatments (P+FS) were highly helpful in alleviating the negative role of cadmium toxicity. The essential nutrients i.e. nitrate (NO3-), calcium (Ca2+) and potassium (K) were affected by Cd+2 induced toxicity however, the substantial role of SA and H2O2 widely helped to reduce the cadmium stress and boosted up the plant nutrients content. In a nutshell, exogenous treatments of SA and H2O2 enhanced the yield potential along with highest silymarin contents in milk thistle seeds which is of prime significance for its medicinal importance in treatment of liver diseases. The data obtained in this study highly recommend the priming and foliar spray of SA and H2O2 on milk thistle plants, as the best solution to alleviative the cadmium toxicity which will ultimately leads to better growth and yield of the plants.

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

Plants ◽  
2020 ◽  
Vol 9 (2) ◽  
pp. 136 ◽  
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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