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1.
Plant Biol (Stuttg) ; 2020 Nov 14.
Artigo em Inglês | MEDLINE | ID: mdl-33188719

RESUMO

Phosphatidic acid (PA) and hydrogen peroxide (H2 O2 ) play roles in regulating plant responses to abiotic stress. The objective of this study was to determine effects of H2 O2 or PA individually and interactively a with a H2 O2 scavenging molecule, N,N'-dimethylthoiurea (DMTU), on plant tolerance to heat stress in tall fescue (Festuca arundinacea). Plants were treated with PA (25 µM), H2 O2 (5 mM) and PA (25 µM) + DMTU (5 mM) by foliar application and then exposed to heat stress (38/33 °C) and optimal temperature (23/18 °C, day/night) for 28 d. Foliar application of PA and H2 O2 alone resulted in increases in leaf fresh weight, chlorophyll content, photochemical efficiency and cellular membrane stability in plants exposed to heat stress, whereas addition of DMTU suppressed the positive effects of PA. The expression levels of genes encoding PA synthesizing enzymes, FaPLDδ, were significantly up-regulated by H2 O2 . PA- or H2 O2 -enhanced heat tolerance was associated with the activation of stress signaling components (FaCDPK3, FaMPK6, FaMPK3), transcription factor (FaMBF1 and FaHsfA2c), and heat shock proteins (FaHSP18, FaHSP70 and FaHSP90). PA and H2 O2 may work coordinately for further improvement in heat tolerance, involving up-regulation of transcriptional factors in stress signaling cascades and heat protection systems.

2.
Plant Cell Physiol ; 2020 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-32931553

RESUMO

Choline, as a precursor of glycine betaine (GB) and phospholipids, is known to play roles in plant tolerance to salt stress, but the downstream metabolic pathways regulated by choline conferring salt tolerance are still unclear for non-GB accumulating species. The objectives were to examine how choline affect salt tolerance in a non-GB accumulating grass species and to determine major metabolic pathways of choline regulating salt tolerance involving GB or lipid metabolism. Kentucky bluegrass (Poa pratensis) plants were subjected to salt stress (100 mM NaCl) with or without foliar application of choline chloride (1 mM) in a growth chamber. Choline or GB alone and the combined application increased leaf photochemical efficiency, relative water content, and osmotic adjustment, and reduced leaf electrolyte leakage. Choline application had no effects on endogenous GB content and GB-synthesis genes did not show responses to choline under non-stress and salt stress conditions. GB was not detected in Kentucky bluegrass leaves. Lipidomic analysis revealed an increase in content of monogalactosyl diacylglycerol, phosphatidylcholine and phosphatidylethanolamine, and a decrease of phosphatidic acid content by choline application in plants exposed to salt stress. Choline-mediated lipid reprogramming could function as a dominant salt tolerance mechanism in non-GB accumulating grass species.

3.
Plant Cell Environ ; 43(1): 159-173, 2020 01.
Artigo em Inglês | MEDLINE | ID: mdl-31600831

RESUMO

Choline may affect salt tolerance by regulating lipid and glycine betaine (GB) metabolism. This study was conducted to determine whether alteration of lipid profiles and GB metabolism may contribute to choline regulation and genotypic variations in salt tolerance in a halophytic grass, seashore paspalum (Paspalum vaginatum). Plants of Adalayd and Sea Isle 2000 were subjected to salt stress (200-mM NaCl) with or without foliar application of choline chloride (1 mM). Genotypic variations in salt tolerance and promotive effects of choline application on salt tolerance were associated with both the up-regulation of lipid metabolism and GB synthesis. The genotypic variations in salt tolerance associated with lipid metabolism were reflected by the differential accumulation of phosphatidylcholine and phosphatidylethanolamine between Adalayd and Sea Isle 2000. Choline-induced salt tolerance was associated with of the increase in digalactosyl diacylglycerol (DGDG) content including DGDG (36:4 and 36:6) in both cultivars of seashore paspalum and enhanced synthesis of phosphatidylinositol (34:2, 36:5, and 36:2) and phosphatidic acid (34:2, 34:1, and 36:5), as well as increases in the ratio of digalactosyl diacylglycerol: monogalactosyl diacylglycerol (DGDG:MGDG) in salt-tolerant Sea Isle 2000. Choline regulation of salt tolerance may be due to the alteration in lipid metabolism in this halophytic grass species.


Assuntos
Betaína/metabolismo , Colina/farmacologia , Metabolismo dos Lipídeos/fisiologia , Paspalum/metabolismo , Tolerância ao Sal/efeitos dos fármacos , Plantas Tolerantes a Sal/metabolismo , Regulação para Cima/efeitos dos fármacos , Regulação da Expressão Gênica de Plantas/efeitos dos fármacos , Metabolismo dos Lipídeos/genética , Paspalum/genética , Desenvolvimento Vegetal , Folhas de Planta/genética , Folhas de Planta/metabolismo , Raízes de Plantas/metabolismo , Estresse Salino , Tolerância ao Sal/genética , Espectrometria de Massas em Tandem
4.
Physiol Plant ; 167(4): 488-501, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-30977137

RESUMO

Abscisic acid (ABA) may play roles in mediating cross stress tolerance in plants. The objectives of this study were to investigate the priming effects of drought and ABA on heat tolerance and to determine how ABA may be involved in enhanced heat tolerance by drought. Focusing on the transcriptional level, two independent experiments were conducted, using a perennial grass species, tall fescue (Festuca arundinacea) and Arabidopsis. In experiment 1, tall fescue plants were exposed to mild drought by withholding irrigation for 8 days (drought priming) and foliar sprayed with ABA or an ABA-synthesis inhibitor (fluridone). After that they were subsequently subjected to heat stress (38/33°C day/night) for 25 days in growth chambers. In experiment 2, Arabidopsis Columbia ecotype (wild-type) and ABA-deficient mutant (aba3-1, CS157) were pre-treated with drought priming and then exposed to heat stress (45/40°C) for 3 days. The physiological analysis demonstrated that both drought priming and foliar application of ABA-enhanced heat tolerance in tall fescue, while drought priming had no significant effects on heat tolerance in ABA-deficient Arabidopsis plants. Application of fluridone to tall fescue and ABA-deficient mutants of Arabidopsis exhibited diminished or attenuated positive effects of drought priming on heat tolerance. ABA mediation of acquired heat tolerance by drought priming was associated with the upregulation of CDPK3, MPK3, DREB2A, AREB3, MYB2, MYC4, HsfA2, HSP18, and HSP70. Our study revealed the roles of ABA in drought priming-enhanced heat tolerance, which may involve transcriptional regulation for stress signaling, ABA responses and heat protection.


Assuntos
Ácido Abscísico/metabolismo , Arabidopsis/fisiologia , Secas , Festuca/fisiologia , Estresse Fisiológico , Termotolerância , Regulação da Expressão Gênica de Plantas , Genes de Plantas , Temperatura Alta
5.
Food Chem ; 277: 524-530, 2019 Mar 30.
Artigo em Inglês | MEDLINE | ID: mdl-30502179

RESUMO

Spring wheat plants were grown under two CO2 concentrations (380 and 550 µmol mol-1) and two temperature treatments (ambient and post-anthesis heat stress) to investigate the effects of elevated CO2 and heat stress on grain protein quality. Contents of protein components, glutenin macropolymers (GMP) and amino acids in grains decreased due to elevated CO2, while increased by high temperature. The combination of elevated CO2 and heat stress increased the contents of total protein and albumin, but decreased the contents of gliadin and glutenin, while the content and particle size distribution of GMP as well as the contents of amino acids were not significantly affected. Furthermore, we found that the content and particle size distribution of GMP were not only determined by the contents of proteins and high-molecular-weight glutenin subunits, but also related to the contents of amino acids containing disulfide bonds, which favor the formation of large insoluble polymers.


Assuntos
Grão Comestível/química , Proteínas de Grãos/análise , Resposta ao Choque Térmico , Triticum/química , Aminoácidos/análise , Dióxido de Carbono/metabolismo , Qualidade dos Alimentos , Gliadina/análise , Glutens/análise , Temperatura Alta , Tamanho da Partícula , Estações do Ano , Proteínas de Armazenamento de Sementes/análise
6.
Plant Cell Environ ; 42(3): 947-958, 2019 03.
Artigo em Inglês | MEDLINE | ID: mdl-29989186

RESUMO

Stress priming by exposing plants to a mild or moderate drought could enhance plant tolerance to subsequent heat stress. Lipids play vital roles in stress adaptation, but how lipidomic profiles change, affecting the cross-stress tolerance, is largely unknown. The objectives of this study were to perform lipidomics, to analyse the content, composition, and saturation levels of lipids in leaves of tall fescue (Festuca arundinacea) following drought priming and subsequent heat stress, and to identify major lipids and molecular species associated with priming-enhanced heat tolerance. Plants were initially exposed to drought for 8 days by withholding irrigation and subsequently subjected to 25 days of heat stress (38/33°C day/night) in growth chambers. Drought-primed plants maintained significantly higher leaf relative water content, chlorophyll content, photochemical efficiency, and lower electrolyte leakage than nonprimed plants under heat stress. Drought priming enhanced the accumulation of phospholipids and glycolipids involved in membrane stabilization and stress signalling (phosphatidic acid, phosphatidylcholine, phosphatidylinositol, phosphatidylglycerol, and digalactosyl diacylglycerol) during subsequent exposure to heat stress. The reprogramming of lipid metabolism for membrane stabilization and signalling in response to drought priming and subsequent exposure to heat stress could contribute to drought priming-enhanced heat tolerance in cool-season grass species.


Assuntos
Festuca/fisiologia , Lipídeos/fisiologia , Adaptação Fisiológica/fisiologia , Desidratação , Festuca/metabolismo , Resposta ao Choque Térmico , Metabolismo dos Lipídeos/fisiologia , Lipidômica
7.
Proteomics ; 18(23): e1800262, 2018 12.
Artigo em Inglês | MEDLINE | ID: mdl-30307109

RESUMO

Elevated CO2 promotes leaf photosynthesis and improves crop grain yield. However, as a major anthropogenic greenhouse gas, CO2 contributes to more frequent and severe heat stress, which threatens crop productivity. The combined effects of elevated CO2 and heat stress are complex, and the underlying mechanisms are poorly understood. In the present study, the effects of elevated CO2 and high-temperature on foliar physiological traits and the proteome of spring wheat grown under two CO2 concentrations (380 and 550 µmol mol-1 ) and two temperature conditions (ambient and post-anthesis heat stress) are examined. Elevated CO2 increases leaf photosynthetic traits, biomass, and grain yield, while heat stress depresses photosynthesis and yield. Temperature-induced impacts on chlorophyll content and grain yield are not significantly different under the two CO2 concentrations. Analysis of the leaf proteome reveals that proteins involved in photosynthesis as well as antioxidant and protein synthesis pathways are significantly downregulated due to the combination of elevated CO2 and heat stress. Correspondingly, plants treated with elevated CO2 and heat stress exhibit decreased green leaf area, photosynthetic rate, antioxidant enzyme activities, and 1000-kernel weight. The present study demonstrates that future post-anthesis heat episodes will diminish the positive effects of elevated CO2 and negatively impact wheat production.


Assuntos
Proteômica/métodos , Triticum/metabolismo , Triticum/fisiologia , Dióxido de Carbono/metabolismo , Resposta ao Choque Térmico/fisiologia
8.
Front Plant Sci ; 9: 261, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29545817

RESUMO

Drought is the major abiotic stress that decreases plant water status, inhibits photosynthesis, induces oxidative stress, restricts growth and finally lead to the reduction of wheat yield. It has been proven that drought priming during vegetative growth stage could enhance tolerance to drought stress at grain filling in wheat. However, whether drought priming imposed at grain filling in parental plants could induce drought tolerance in the offspring is not known. In this study, drought priming was successively applied in the first, the second and the third generation of wheat to obtain the plants of T1 (primed for one generation), T2 (primed for two generations), T3 (primed for three generations). The differently primed plants were then subjected to drought stress during grain filling in the fourth generation. Under drought stress, the parentally primed (T1D, T2D, T3D) plants, disregarding the number of generations, showed higher grain yield, leaf photosynthetic rate and antioxidant capacity as well as lower [Formula: see text] release rate and contents of H2O2 and MDA than the non-primed (T0D) plants, suggesting that drought priming induced the transgenerational stress tolerance to drought stress. Moreover, the parentally primed plants showed higher leaf water status, which may result from the higher contents of proline and glycine betaine, and higher activities of Δ1-pyrroline-5-carboxylate synthetase (P5CS) and betaine aldehyde dehydrogenase (BADH), compared with the non-primed plants under drought stress. In addition, there was no significant difference among three generations under drought, and the drought priming in parental generations did not affect the grain yield of the offspring plants under control condition. Collectively, the enhanced accumulation of proline and glycine betaine in the parentally primed plants could have played critical roles in parental priming induced tolerance to drought stress. This research provided a potential approach to improve drought tolerance of offspring plants by priming parental plants.

9.
Food Chem ; 197(Pt A): 516-21, 2016 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-26616983

RESUMO

Addition of salt solution in making wheat dough improves viscoelasticity. However, the effect of native salt fortification on dough quality is unclear. Here, wheat plants were subjected to post-anthesis salt stress to modify salt ion content in grains. The contents of Na(+) and K(+), high-molecular-weight glutenin subunits (HMW-GS), glutenin macropolyers (GMP) and amino acids in mature grains were measured. As NaCl concentration in soil increased, grain yield decreased while Na(+) and K(+) contents increased. The contents of amino acids, HMW-GS and GMP in grains also increased, especially when NaCl concentration exceeded 0.45%. Fraction of GMP larger than 10 µm was also increased. Na(+) and K(+) contents were significantly positively correlated to GMP and total HMW-GS contents, and to large GMP fraction.


Assuntos
Glutens/química , Cloreto de Sódio/metabolismo , Triticum/química , Glutens/metabolismo , Peso Molecular , Polimerização , Triticum/crescimento & desenvolvimento , Triticum/metabolismo
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