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 Paternal effects in a wild‐type zebrafish implicate a role of sperm‐derived small RNAs

2020 ◽  
Vol 29 (14) ◽  
pp. 2722-2735
Author(s):  
James Ord ◽  
Paul R. Heath ◽  
Alireza Fazeli ◽  
Penelope J. Watt
Keyword(s):  
Small Rnas ◽  
Wild Type ◽  
Paternal Effects

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 Protease-mediated processing of Argonaute proteins controls small RNA association

2020 ◽  
Author(s):  
Rajani Kanth Gudipati ◽  
Kathrin Braun ◽  
Foivos Gypas ◽  
Daniel Hess ◽  
Jan Schreier ◽  
...  
Keyword(s):  
Small Rna ◽  
Small Rnas ◽  
Proteolytic Processing ◽  
Genome Integrity ◽  
Wild Type ◽  
Selfish Genetic Elements ◽  
Argonaute Proteins ◽  
Processing Activity ◽  
Rna Pathways

SummarySmall RNA pathways defend the germlines of animals against selfish genetic elements and help to maintain genomic integrity. At the same time, their activity needs to be well-controlled to prevent silencing of ‘self’ genes. Here, we reveal a proteolytic mechanism that controls endogenous small interfering (22G) RNA activity in the Caenorhabditis elegans germline to protect genome integrity and maintain fertility. We find that WAGO-1 and WAGO-3 Argonaute (Ago) proteins are matured through proteolytic processing of their unusually proline-rich N-termini. In the absence of DPF-3, a P-granule-localized N-terminal dipeptidase orthologous to mammalian DPP8/9, processing fails, causing a change of identity of 22G RNAs bound to these WAGO proteins. Desilencing of repeat- and transposon-derived transcripts, DNA damage and acute sterility ensue. These phenotypes are recapitulated when WAGO-1 and WAGO-3 are rendered resistant to DFP-3-mediated processing, identifying them as critical substrates of DPF-3. We conclude that N-terminal processing of Ago proteins regulates their activity and promotes discrimination of self from non-self by ensuring association with the proper complement of small RNAs.Graphical Abstract: The role of DPF-3 in the fertility of the animalsIn wild type animals, the WAGO-1 and WAGO-3 Argonaute proteins are produced as immature pro-proteins with N-termini (N) that are unusually rich in prolines (P). N-terminal processing by DPF-3 is required for loading of the proper small RNA cargo and stabilization of WAGO-3. Accordingly, loss of this processing activity causes desilencing of transposable elements (TE), cell death and sterility.

scholarly journals Overexpression of Mannitol-1-Phosphate Dehydrogenase Increases Mannitol Accumulation and Adds Protection Against Chilling Injury in Petunia

2005 ◽  
Vol 130 (4) ◽  
pp. 605-610 ◽  
Author(s):  
Yu-Jen Chiang ◽  
C. Stushnoff ◽  
A.E. McSay ◽  
M.L. Jones ◽  
H.J. Bohnert
Keyword(s):  
Chilling Stress ◽  
Chilling Injury ◽  
Dry Weight ◽  
Wild Type ◽  
Gene Encoding ◽  
E Coli ◽  
Horticultural Crops ◽  
Transgenic Lines ◽  
And Control

Petunia ×hybrida (Hook) Vilm. cv. Mitchell was transformed with an E. coli gene encoding mannitol-1-phosphate dehydrogenase (mtlD). Four plant lines that grew on kanamycin and contained the mtlD transgene were identified. Two of these lines contained high levels of mannitol [high-mannitol lines M3 and M8; mean mannitol = 3.39 μmol·g-1 dry weight (DW)] compared to nontransformed wild-type plants (0.86 μmol·g-1 DW), while two lines had mannitol levels similar to wild-type plants (low-mannitol lines M2 and M9; mean mannitol = 1.05 μmol·g-1 DW). Transgenic and control plants were subjected to chilling stress (3 ± 0.5 °C day/0 ± 0.5 °C night, 12-hour photoperiod and 75% relative humidity) to evaluate the role of mannitol in chilling tolerance. Based upon foliage symptoms and membrane leakage after a 3-week chilling treatment, the high-mannitol containing lines, M3 and M8, were more tolerant of chilling stress than the low-mannitol containing transgenic lines, M2 and M9, and wild-type. Under nonchilling conditions mannitol was the only carbohydrate that differed among transgenic lines, but all carbohydrates were present. When subjected to chilling stress, mannitol levels dropped by 75%, sucrose by 52%, and inositol by 54% in the low-mannitol lines (M2 and M9). In M3 and M8, the high-mannitol lines, mannitol levels decreased by 36%, sucrose by 25%, and inositol by 56%, respectively. Raffinose increased 2- to 3-fold in all lines following exposure to low-temperature chilling stress. In the higher mannitol lines only 0.04% to 0.06% of the total osmotic potential generated from all solutes could be attributed to mannitol, thus its action is more like that of an osmoprotectant rather than an osmoregulator. This study demonstrates that metabolic engineering of osmoprotectant synthesis pathways can be used to improve stress tolerance in horticultural crops.

Phytochrome, photosynthesis and flowering of Arabidopsis thaliana: photophysiological studies using mutants and transgenic lines

2001 ◽  
Vol 28 (5) ◽  
pp. 401 ◽  
Author(s):  
David J. Bagnall ◽  
Rod W. King
Keyword(s):  
Arabidopsis Thaliana ◽  
Photoperiodic Response ◽  
High Irradiance ◽  
Phytochrome A ◽  
Wild Type ◽  
Long Day ◽  
Transgenic Lines ◽  
A Minor ◽  
Type Response ◽  
Plant Arabidopsis Thaliana

A number of phytochrome mutants have been examined for involvement in high irradiance (HIR) or red/far-red (R/FR) end-of-day (EOD) photoresponses during flowering of the long-day (LD) plant, Arabidopsis thaliana (L.) Heynh. A large component of phytochrome A (phyA) response is shown to involve an indirect effect via photosynthesis. When grown autotrophically in soil at a low irradiance (80 mol m–2 s–1), the phyA-211 mutant flowered extremely late compared with wild type and its leaf area was halved, both effects being reversed by increase in photosynthetic irradiance. Supplying sucrose via agar led to very early flowering with little indication of an additional direct phyA HIR. For light-stable phytochrome apoprotein mutants (phyB, phyD) or chromophore mutants (hy1, hy2), flowering was early and R/FR photoreversible EOD response was erased. Conversely, flowering was delayed in a transgenic line overexpressing the PHYB apoprotein. The FR EOD promotion of flowering via phyB was retained in darkness, brief night interruptions mimicking LD response. This novel finding emphasizes the importance of phyB-like phytochromes, with phyA acting indirectly. Whether phyB influences time measurement remains uncertain as we found no rhythmicity in this response to night interruptions. Overall, the role(s) of phytochromes in the regulation of flowering of Arabidopsis include EOD phyB-type response, a minor phyA photoperiodic response, and a large indirect phyA effect involving photosynthesis.

scholarly journals Constitutive cyclic GMP accumulation in Arabidopsis thaliana compromises systemic acquired resistance induced by an avirulent pathogen by modulating local signals

2016 ◽  
Vol 6 (1) ◽  
Author(s):  
Jamshaid Hussain ◽  
Jian Chen ◽  
Vittoria Locato ◽  
Wilma Sabetta ◽  
Smrutisanjita Behera ◽  
...  
Keyword(s):  
Arabidopsis Thaliana ◽  
Large Scale ◽  
Systemic Acquired Resistance ◽  
Soluble Guanylate Cyclase ◽  
Acquired Resistance ◽  
Plant Defence ◽  
Redox System ◽  
Wild Type ◽  
Transgenic Lines ◽  
Defence Responses

Abstract The infection of Arabidopsis thaliana plants with avirulent pathogens causes the accumulation of cGMP with a biphasic profile downstream of nitric oxide signalling. However, plant enzymes that modulate cGMP levels have yet to be identified, so we generated transgenic A. thaliana plants expressing the rat soluble guanylate cyclase (GC) to increase genetically the level of cGMP and to study the function of cGMP in plant defence responses. Once confirmed that cGMP levels were higher in the GC transgenic lines than in wild-type controls, the GC transgenic plants were then challenged with bacterial pathogens and their defence responses were characterized. Although local resistance was similar in the GC transgenic and wild-type lines, differences in the redox state suggested potential cross-talk between cGMP and the glutathione redox system. Furthermore, large-scale transcriptomic and proteomic analysis highlighted the significant modulation of both gene expression and protein abundance at the infection site, inhibiting the establishment of systemic acquired resistance. Our data indicate that cGMP plays a key role in local responses controlling the induction of systemic acquired resistance in plants challenged with avirulent pathogens.

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.

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 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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