Comparison of full-length and conserved segments of wheat dehydrin DHN-5 overexpressed in Arabidopsis thaliana showed different responses to abiotic and biotic stress

2016 ◽  
Vol 43 (11) ◽  
pp. 1048 ◽  
Author(s):  
Marwa Drira ◽  
Moez Hanin ◽  
Khaled Masmoudi ◽  
Faiçal Brini
Keyword(s):  
Arabidopsis Thaliana ◽  
Fungal Infections ◽  
Alternaria Solani ◽  
Triticum Aestivum L ◽  
Full Length ◽  
Plant Tolerance ◽  
Wild Type ◽  
Biotic And Abiotic Stresses ◽  
Related Stress

Dehydrins (DHNs) are among the most common proteins accumulated in plants under water-related stress. They typically contain at least three conserved sequences designated as the Y-, S- and K-segments. The present work aims to highlight the role of the K-segments in plant tolerance to biotic and abiotic stresses. For this purpose, transgenic Arabidopsis thaliana (L.) Heyhn. lines expressing distinct wheat (Triticum aestivum L.) DHN-5 truncated constructs with or without the K-segments were generated. Our results showed that unlike the derivative lacking a K-segment, constructs containing only one or two K-segments enhanced the tolerance of A. thaliana to diverse stresses and were similar to the full-length wheat DHN-5. Moreover, compared with the wild-type and the YS form, the transgenic plants overexpressing wheat DHN-5 with K-segments maintained higher superoxide dismutase, catalase and peroxide dismutase enzymatic activity, and accumulated lower levels of H2O2 and malondialdehyde. In addition, we demonstrated that lines like A. thaliana overexpressing wheat DHN-5 showed increased resistance to fungal infections caused by Botrytis cinerea and Alternaria solani. Finally, the overexpression of the different forms of wheat DHN-5 led to the regulation of the expression of several genes involved in the jasmonic acid signalling pathway.

scholarly journals Seed Gamma Irradiation of Arabidopsis thaliana ABA-Mutant Lines Alters Germination and Does Not Inhibit the Photosynthetic Efficiency of Juvenile Plants

Dose-Response ◽  
2020 ◽  
Vol 18 (4) ◽  
pp. 155932582097924
Author(s):  
Darya Babina ◽  
Marina Podobed ◽  
Ekaterina Bondarenko ◽  
Elizaveta Kazakova ◽  
Sofia Bitarishvili ◽  
...  
Keyword(s):  
Arabidopsis Thaliana ◽  
Growth Response ◽  
Dose Range ◽  
Fine Tuning ◽  
Plant Tolerance ◽  
Inhibitory Effects ◽  
Γ Irradiation ◽  
Photosynthetic Responses ◽  
Mutant Lines

Plant growth response to γ-irradiation includes stimulating or inhibitory effects depending on plant species, dose applied, stage of ontogeny and other factors. Previous studies showed that responses to irradiation could depend on ABA accumulation and signaling. To elucidate the role of ABA in growth and photosynthetic responses to irradiation, lines Col-8, abi3-8 and aba3 -1 of Arabidopsis thaliana were used. Seeds were γ-irradiated using 60Co in the dose range 50-150 Gy. It was revealed that the dose of 150 Gy affected germination parameters of aba3 -1 and Col-8 lines, while abi3-8 line was the most resistant to the studied doses and even showed faster germination at early hours after γ-irradiation at 50 Gy. These results suggest that susceptibility to ABA is probably more important for growth response to γ-irradiation than ABA synthesis. The photosynthetic functioning of 16-day-old plants mainly was not disturbed by γ-irradiation of seeds, and no indication of photosystem II photoinhibition was noticed, revealing the robustness of the photosynthetic system of A. thaliana. Glutathione peroxidase activity and ABA concentrations in plant tissues were not affected in the studied dose range. These results contribute to the understanding of germination and photosynthesis fine-tuning and of mechanisms of plant tolerance to ionizing radiation.

scholarly journals Conserved Cu-MicroRNAs in Arabidopsis thaliana Function in Copper Economy under Deficiency

Plants ◽  
2019 ◽  
Vol 8 (6) ◽  
pp. 141 ◽  
Author(s):  
Muhammad Shahbaz ◽  
Marinus Pilon
Keyword(s):  
Arabidopsis Thaliana ◽  
Small Rnas ◽  
Wild Type ◽  
Microrna Target ◽  
Electron Carrier ◽  
Cu Deficiency ◽  
Regulatory Circuits ◽  
Transgenic Lines ◽  
Cu Homeostasis

Copper (Cu) is a micronutrient for plants. Three small RNAs, which are up-regulated by Cu deficiency and target transcripts for Cu proteins, are among the most conserved microRNAs in plants. It was hypothesized that these Cu-microRNAs help save Cu for the most essential Cu-proteins under deficiency. Testing this hypothesis has been a challenge due to the redundancy of the Cu microRNAs and the properties of the regulatory circuits that control Cu homeostasis. In order to investigate the role of Cu-microRNAs in Cu homeostasis during vegetative growth, we used a tandem target mimicry strategy to simultaneously inhibit the function of three conserved Cu-microRNAs in Arabidopsis thaliana. When compared to wild-type, transgenic lines that express the tandem target mimicry construct showed reduced Cu-microRNA accumulation and increased accumulation of transcripts that encode Cu proteins. As a result, these mimicry lines showed impaired photosynthesis and growth compared to wild type on low Cu, which could be ascribed to a defect in accumulation of plastocyanin, a Cu-containing photosynthetic electron carrier, which is itself not a Cu-microRNA target. These data provide experimental support for a Cu economy model where the Cu-microRNAs together function to allow maturation of essential Cu proteins under impending deficiency.

scholarly journals Sulfite Oxidase Activity Level Determines the Sulfite Toxicity Effect in Leaves and Fruits of Tomato Plants

Agronomy ◽  
2020 ◽  
Vol 10 (5) ◽  
pp. 694
Author(s):  
Umanath Sharma ◽  
Aizat Bekturova ◽  
Yvonne Ventura ◽  
Moshe Sagi
Keyword(s):  
Sulfite Oxidase ◽  
Activity Level ◽  
Vegetable Crops ◽  
Plant Tolerance ◽  
Wild Type ◽  
Biotic And Abiotic Stresses ◽  
Tomato Plants ◽  
Leaf Discs ◽  
Toxicity Effect ◽  
Treated Leaf

Increasing plant tolerance to sulfites/SO2 can lead to the development of tolerant crops to biotic and abiotic stresses. Plant sulfite oxidase (SO) is a molybdo-enzyme that oxidizes excess SO2/sulfite into non-toxic sulfate. The effect of toxic sulfite on leaves and fruits was studied in tomato plants with different SO expression: wild-type, SO overexpression (OE) and SO RNA interference (Ri). Sulfite-dipped ripe-fruits and sulfite treated leaf discs of Ri plants impaired in SO activity were more susceptible, whereas OE plants were more resistant, as revealed by remaining chlorophyll and tissue damage levels. Application of molybdenum further enhanced the tolerance of leaf discs to sulfite by enhancing SO activity in OE lines, but not in wild-type or Ri plants. Notably, incubation with tungsten, the molybdenum antagonist, overturned the effect of molybdenum spray in OE plants, revealed by remaining chlorophyll content and SO activity. The results indicate that SO in tomato leaves and ripe fruits determines the resistance to sulfite and the application of molybdenum enhances sulfite resistance in OE plants by increasing SO activity. Overall, the results suggest that SO overexpression can be employed, with or without molybdenum application, for developing fruit and vegetable crops tolerant to sulfite/SO2 containing pre- and postharvest treatments.

scholarly journals ROS-Scavengers, Osmoprotectants and Violaxanthin De-Epoxidation in Salt-Stressed Arabidopsis thaliana with Different Tocopherol Composition

2021 ◽  
Vol 22 (21) ◽  
pp. 11370
Author(s):  
Ewa Surówka ◽  
Dariusz Latowski ◽  
Michał Dziurka ◽  
Magdalena Rys ◽  
Anna Maksymowicz ◽  
...  
Keyword(s):  
Arabidopsis Thaliana ◽  
Salt Stress ◽  
Transgenic Line ◽  
Wild Type ◽  
Carbon And Nitrogen ◽  
Nacl Concentration ◽  
Tocopherol Composition ◽  
Ros Scavengers ◽  
Excessive Accumulation

To determine the role of α- and γ-tocopherol (TC), this study compared the response to salt stress (200 mM NaCl) in wild type (WT) Arabidopsis thaliana (L.) Heynh. And its two mutants: (1) totally TC-deficient vte1; (2) vte4 accumulating γ-TC instead of α-TC; and (3) tmt transgenic line overaccumulating α-TC. Raman spectra revealed that salt-exposed α-TC accumulating plants were more flexible in regulating chlorophyll, carotenoid and polysaccharide levels than TC deficient mutants, while the plants overaccumulating γ-TC had the lowest levels of these biocompounds. Tocopherol composition and NaCl concentration affected xanthophyll cycle by changing the rate of violaxanthin de-epoxidation and zeaxanthin formation. NaCl treated plants with altered TC composition accumulated less oligosaccharides than WT plants. α-TC deficient plants increased their oligosaccharide levels and reduced maltose amount, while excessive accumulation of α-TC corresponded with enhanced amounts of maltose. Salt-stressed TC-deficient mutants and tmt transgenic line exhibited greater proline levels than WT plants, lower chlorogenic acid levels, and lower activity of catalase and peroxidases. α-TC accumulating plants produced more methylated proline- and glycine- betaines, and showed greater activity of superoxide dismutase than γ-TC deficient plants. Under salt stress, α-TC demonstrated a stronger regulatory effect on carbon- and nitrogen-related metabolites reorganization and modulation of antioxidant patterns than γ-TC. This suggested different links of α- and γ-TCs with various metabolic pathways via various functions and metabolic loops.

scholarly journals Melatonin Enhanced the Tolerance of Arabidopsis thaliana to High Light Through Improving Anti-oxidative System and Photosynthesis

2021 ◽  
Vol 12 ◽  
Author(s):  
Si-Jia Yang ◽  
Bo Huang ◽  
Yu-Qing Zhao ◽  
Di Hu ◽  
Tao Chen ◽  
...  
Keyword(s):  
Arabidopsis Thaliana ◽  
Light Stress ◽  
Photosynthetic Apparatus ◽  
High Light ◽  
Protective Effects ◽  
Biotic And Abiotic Stresses ◽  
Exogenous Melatonin ◽  
Sunlight Intensity ◽  
Oxidative System

Land plants live in a crisis-filled environment and the fluctuation of sunlight intensity often causes damage to photosynthetic apparatus. Phyto-melatonin is an effective bioactive molecule that helps plants to resist various biotic and abiotic stresses. In order to explore the role of melatonin under high light stress, we investigated the effects of melatonin on anti-oxidative system and photosynthesis of Arabidopsis thaliana under high light. Results showed that exogenous melatonin increased photosynthetic rate and protected photosynthetic proteins under high light. This was mainly owing to the fact that exogenous melatonin effectively decreased the accumulation of reactive oxygen species and protected integrity of membrane and photosynthetic pigments, and reduced cell death. Taken together, our study promoted more comprehensive understanding in the protective effects of exogenous melatonin under high light.

scholarly journals Oligomerization and hemolytic properties of the C-terminal domain of pyolysin, a cholesterol-dependent cytolysin

2013 ◽  
Vol 91 (2) ◽  
pp. 59-66 ◽  
Author(s):  
Lisa Pokrajac ◽  
J. Robin Harris ◽  
Naghmeh Sarraf ◽  
Michael Palmer
Keyword(s):  
Full Length ◽  
Membrane Insertion ◽  
Wild Type ◽  
Terminal Domain ◽  
Large Size ◽  
Monomer Structure ◽  
Streptolysin O ◽  
Kinetics Of ◽  
Domain 4

Pyolysin (PLO) belongs to the homologous family of the cholesterol-dependent cytolysins (CDCs), which bind to cell membranes containing cholesterol to form oligomeric pores of large size. The CDC monomer structure consists of 4 domains. Among these, the C-terminal domain 4 has been implicated in membrane binding of the monomer, while the subsequent processes of oligomerization and membrane insertion have primarily been assigned to other domains of the molecule. Recombinantly expressed or proteolytic fragments that span domain 4 of the CDCs streptolysin O and perfringolysin O bind to membranes but fail to oligomerize, and they inhibit the activity of the respective wild-type toxins. We report here that the isolated domain 4 of pyolysin (PLO-D4) not only binds to membranes but also forms oligomers with itself, as well as hybrid oligomers with the full-length toxin. As expected, the pure PLO-D4 oligomers are devoid of pore-forming activity. Surprisingly, however, within hybrid oligomers, PLO-D4 not only fails to inhibit, but even amplifies the hemolytic activity of the full-length toxin, to an extent similar to that of doubling the amount of the full-length toxin alone. We propose that this amplification may be related to the kinetics of the oligomerization reaction. Overall, our findings indicate a greater role of domain 4 in the oligomerization of CDCs than previously demonstrated.

scholarly journals Revisiting the Role of Ethylene and N-End Rule Pathway on Chilling-Induced Dormancy Release in Arabidopsis Seeds

2018 ◽  
Vol 19 (11) ◽  
pp. 3577 ◽  
Author(s):  
Xu Wang ◽  
Zhazira Yesbergenova-Cuny ◽  
Catherine Biniek ◽  
Christophe Bailly ◽  
Hayat El-Maarouf-Bouteau ◽  
...  
Keyword(s):  
Arabidopsis Thaliana ◽  
Signaling Pathway ◽  
Dormancy Release ◽  
Ethylene Signaling ◽  
Aba Signaling ◽  
Wild Type ◽  
Ethylene Signaling Pathway

Dormant Arabidopsis (Arabidopsis thaliana) seeds do not germinate easily at temperatures higher than 10–15 °C. Using mutants affected in ethylene signaling (etr1, ein2 and ein4) and in the N-end-rule pathway of the proteolysis (prt6 and ate1-ate2) we have investigated the effects of cold and ethylene on dormancy alleviation. Ethylene (10–100 ppm) and 2–4 days chilling (4 °C) strongly stimulate the germination of wild type (Col-0) seeds at 25 °C. Two to four days of chilling promote the germination at 25 °C of all the mutants suggesting that release of dormancy by cold did not require ethylene and did not require the N-end-rule pathway. One mutant (etr1) that did not respond to ethylene did not respond to GA3 either. Mutants affected in the N-end rule (prt6 and ate1-ate2) did not respond to ethylene indicating that also this pathway is required for dormancy alleviation by ethylene; they germinated after chilling and in the presence of GA3. Cold can activate the ethylene signaling pathway since it induced an accumulation of ETR1, EINI4, and EIN2 transcripts, the expression of which was not affected by ethylene and GA3. Both cold followed by 10 h at 25 °C and ethylene downregulated the expression of PRT6, ATE1, ATE2, and of ABI5 involved in ABA signaling as compared to dormant seeds incubated at 25 °C. In opposite, the expression of RGA, GAI, and RGL2 encoding three DELLAs was induced at 4 °C but downregulated in the presence of ethylene.

scholarly journals The Role of GRASP55 in Golgi Fragmentation and Entry of Cells into Mitosis

2008 ◽  
Vol 19 (6) ◽  
pp. 2579-2587 ◽  
Author(s):  
Juan Manuel Duran ◽  
Matt Kinseth ◽  
Carine Bossard ◽  
David W. Rose ◽  
Roman Polishchuk ◽  
...  
Keyword(s):  
Peptide Mapping ◽  
Full Length ◽  
Wild Type ◽  
Experimental Conditions ◽  
Golgi Membranes ◽  
Golgi Fragmentation ◽  
Per Se ◽  
Golgi Organization

GRASP55 is a Golgi-associated protein, but its function at the Golgi remains unclear. Addition of full-length GRASP55, GRASP55-specific peptides, or an anti-GRASP55 antibody inhibited Golgi fragmentation by mitotic extracts in vitro, and entry of cells into mitosis. Phospho-peptide mapping of full-length GRASP55 revealed that threonine 225 and 249 were mitotically phosphorylated. Wild-type peptides containing T225 and T249 inhibited Golgi fragmentation and entry of cells into mitosis. Mutant peptides containing T225E and T249E, in contrast, did not affect Golgi fragmentation and entry into mitosis. These findings reveal a role of GRASP55 in events leading to Golgi fragmentation and the subsequent entry of cell into mitosis. Surprisingly, however, under our experimental conditions, >85% knockdown of GRASP55 did not affect the overall organization of Golgi organization in terms of cisternal stacking and lateral connections between stacks. Based on our findings we suggest that phosphorylation of GRASP55 at T225/T249 releases a bound component, which is phosphorylated and necessary for Golgi fragmentation. Thus, GRASP55 has no role in the organization of Golgi membranes per se, but it controls their fragmentation by regulating the release of a partner, which requires a G2-specific phosphorylation at T225/T249.

scholarly journals Heat and cold stresses phenotypes of Arabidopsis thaliana calmodulin mutants: regulation of gamma-aminobutyric acid shunt pathway under temperature stress

2012 ◽  
Vol 3 (1) ◽  
pp. 2 ◽  
Author(s):  
Nisreen A. AL-Quraan ◽  
Robert D. Locy ◽  
Narendra K. Singh
Keyword(s):  
Arabidopsis Thaliana ◽  
Heat Stress ◽  
High Temperature ◽  
Seed Germination ◽  
Oxidative Damage ◽  
Temperature Stress ◽  
Wild Type ◽  
Gaba Shunt ◽  
Heat And Cold Stress

Plants have evolved mechanisms to cope with changes in surrounding temperatures. T-DNA insertions in seven calmodulin genes of <em>Arabidopsis thaliana</em> were used to investigate the role of specific calmodulin isoforms in tolerance of plants to low and high temperature for seed germination, susceptibility to low and high temperature induced oxidative damage, and changes in the levels of gammaaminobutyric acid (GABA) shunt metabolites in response to temperature stress. Exposure of wild type (WT) and <em>cam</em> mutant seeds at 4°C showed reduction in germination of <em>cam5-4</em> and <em>cam6-1</em> seeds. Exposure of cam seedlings to 42°C for 2 hr showed reduction in seed germination and survival of seedlings in <em>cam5-4</em> and <em>cam6-1</em> mutants compared to WT and other <em>cam</em> mutants. Oxidative damage by heat and cold stress measured as the level of malonaldehyde (MDA) was detected increased in root and shoot tissues of cam5- 4 and cam6-1. Oxidative damage by heat measured as the level of MDA was detected in root and shoot of most cam mutants with highest levels in <em>cam5-4</em> and <em>cam6-1</em>. Level of GABA shunt metabolites in seedlings were gradually increased after 1 hr and 3 hr with maximum level after 6 hr and 12 hr treatments at 4ºC. GABA shunt metabolites in both root and shoot were generally elevated after 30 min and 1 hr treatment at 42°C, and increased substantially after 2 hr at 42°C comparing to the control (no treatment). GABA and glutamate levels were increased significantly more than alanine in root and shoot tissues of all cam mutants and wild type compared to the control. Alanine levels showed significant decreases in all cam mutants and in WT for 30 and 60 min of heat stress. Sensitivity of <em>cam5-4 </em>and <em>cam6-1</em> to low temperatures suggests a role of the <em>CAM5</em> and <em>CAM6</em> genes in seed germination and protection against cold induced oxidative damage. Increases in the level of GABA shunt metabolites in response to cold treatment after initial reduction in some cam mutants suggests a role for calmodulin protein (<em>cam</em>) in the activation of glutamate decarboxylase (GAD) after exposure to cold, while increased metabolite levels may indicate involvement of other factors like reduction in cytoplasmic pH in cold regulation. Initial general elevation in GABA shunt metabolites after 30 min heat treatment in cam mutants suggests regulation of GABA level by <em>cam</em>. These data suggest that regulation by factors other than cam is likely, and that this factor may relate to the regulation of GAD by intracellular pH and/or metabolite partitioning under heat stress.

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