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1.
Nat Commun ; 11(1): 5085, 2020 10 08.
Artigo em Inglês | MEDLINE | ID: mdl-33033250

RESUMO

Tibetan wheat is grown under environmental constraints at high-altitude conditions, but its underlying adaptation mechanism remains unknown. Here, we present a draft genome sequence of a Tibetan semi-wild wheat (Triticum aestivum ssp. tibetanum Shao) accession Zang1817 and re-sequence 245 wheat accessions, including world-wide wheat landraces, cultivars as well as Tibetan landraces. We demonstrate that high-altitude environments can trigger extensive reshaping of wheat genomes, and also uncover that Tibetan wheat accessions accumulate high-altitude adapted haplotypes of related genes in response to harsh environmental constraints. Moreover, we find that Tibetan semi-wild wheat is a feral form of Tibetan landrace, and identify two associated loci, including a 0.8-Mb deletion region containing Brt1/2 homologs and a genomic region with TaQ-5A gene, responsible for rachis brittleness during the de-domestication episode. Our study provides confident evidence to support the hypothesis that Tibetan semi-wild wheat is de-domesticated from local landraces, in response to high-altitude extremes.


Assuntos
Adaptação Fisiológica , Altitude , Triticum/fisiologia , Adaptação Fisiológica/genética , Domesticação , Ecótipo , Genoma de Planta , Geografia , Metagenômica , Fenótipo , Análise de Componente Principal , Tibet , Triticum/genética
2.
Ecotoxicol Environ Saf ; 205: 111346, 2020 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-32977285

RESUMO

It is a daunting challenge to predict toxicity and accumulation of rare earth metals (REMs) in different exposure scenarios (e.g., varying water chemistry and metal combinations). Herein, we investigated the toxicity and uptake of La and Ce in the presence of various levels of Ca, Mg, Na, K, and at different pH values, as well as the combined effects of La and Ce in wheat Triticum aestivum. Major cations (Ca2+ and Mg2+) significantly mitigated the toxicity and accumulation of La3+/Ce3+. Toxicity and uptake of La, Ce, and La-Ce mixtures could be well quantified by the multi-metal biotic ligand model (BLM) and by the Langmuir-type uptake model with the consideration of the competitive effects of Ca2+ and Mg2+, with more than 85.1% of variations explained. The derived binding constants of Ca, Mg, La, and Ce to wheat root were respectively 3.87, 3.59, 6.97, and 6.48 on the basis of toxicity data, and 3.23, 2.84, 6.07, and 5.27 on the basis of uptake data. The use of the alternative WHAM-Ftox approach, requiring fewer model parameters than the BLM but with similar Akaike information criterion (AIC) values, successfully predicted the toxicity and accumulation of La/Ce as well as toxicity of La-Ce mixtures, with at least 76.4% of variations explained. However, caution should be taken when using this approach to explain the uptake of La-Ce mixtures. Our results provided promising tools for delineating REMs toxicity/uptake in the presence of other toxicity-modifying factors or in mixture scenarios.


Assuntos
Metais Terras Raras/toxicidade , Triticum/fisiologia , Disponibilidade Biológica , Cátions/farmacologia , Ligantes , Metais/farmacologia , Modelos Biológicos , Sódio , Triticum/efeitos dos fármacos
3.
Nat Commun ; 11(1): 4408, 2020 09 02.
Artigo em Inglês | MEDLINE | ID: mdl-32879311

RESUMO

Understanding extreme weather impacts on staple crops such as wheat is vital for creating adaptation strategies and increasing food security, especially in dryland cropping systems across Southern Africa. This study analyses heat impacts on wheat using daily weather information and a dryland wheat dataset for 71 cultivars across 17 locations in South Africa from 1998 to 2014. We estimate temperature impacts on yields in extensive regression models, finding that extreme heat drives wheat yield losses, with an additional 24 h of exposure to temperatures above 30 °C associated with a 12.5% yield reduction. Results from a uniform warming scenario of +1 °C show an average wheat yield reduction of 8.5%, which increases to 18.4% and 28.5% under +2 and +3 °C scenarios. We also find evidence of differences in heat effects across cultivars, which suggests warming impacts may be reduced through the sharing of gene pools amongst wheat breeding programs.


Assuntos
Adaptação Fisiológica , Produtos Agrícolas , Triticum , Cruzamento/métodos , Mudança Climática , Produtos Agrícolas/crescimento & desenvolvimento , Produtos Agrícolas/fisiologia , Genótipo , Aquecimento Global , Temperatura Alta , África do Sul , Triticum/genética , Triticum/crescimento & desenvolvimento , Triticum/fisiologia
4.
Chemosphere ; 260: 127652, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-32688325

RESUMO

Cadmium (Cd) contamination in soil negatively impacts crop productivity, grain quality, and human health. Wheat seeds, with different concentrations of intrinsic zinc (Zn): low Zn (35 mg kg-1), medium (42 mg kg-1), and high Zn (49 mg kg-1), were planted in artificially contaminated soil (10 mg Cd kg-1 soil). Zinc (5 g kg-1) and biochar (20 g kg-1 soil) were applied alone or in combination at sowing. Cadmium contamination reduced wheat growth, productivity, and grain Zn concentration, relative to the respective no-Cd treatments, with greater reductions in plants with low intrinsic Zn. Among the soil amendments, Zn and/or biochar improved wheat productivity and grain Zn and reduced grain Cd concentration in plants grown from seed with varying intrinsic Zn levels. Plants from high intrinsic Zn seeds performed better under Cd stress with the application of soil amendments than seeds with low or medium intrinsic Zn levels. The combined application of Zn and biochar had the highest increases in grain yield (9.51%) and grain Zn concentration (12.2%), relative to the control (no Cd, no Zn, and no biochar). This treatment also decreased the Cd concentrations in straw (7.1%) and grain (95.6%). The sole application of Zn or biochar improved wheat productivity and grain Zn concentration and deceased grain Cd concentration under Cd stress, but more improvements resulted from the combined application of Zn and biochar. Plants grown from seed with high Zn were better able to tolerate Cd stress than the plants raised from seeds with medium and low Zn levels.


Assuntos
Cádmio/toxicidade , Poluentes do Solo/toxicidade , Triticum/fisiologia , Zinco/análise , Pão , Cádmio/química , Carvão Vegetal , Grão Comestível/química , Poluição Ambiental , Humanos , Sementes/química , Solo , Poluentes do Solo/análise , Poluentes do Solo/química , Triticum/crescimento & desenvolvimento
5.
PLoS One ; 15(7): e0236317, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32702002

RESUMO

Heterodera avenae, as an obligate endoparasite, causes severe yield loss in wheat (Triticum aestivum). Investigation on the mechanisms how H. avenae perceives wheat roots is limited. Here, the attractiveness of root exudates from eight plant genotypes to H. avenae were evaluated on agar plates. Results showed that the attraction of H. avenae to the root exudates from the non-host Brachypodium distachyon variety Bd21-3 was the highest, approximately 50 infective second-stage juveniles (J2s) per plate, followed by that from three H. avenae-susceptible wheat varieties, Zhengmai9023, Yanmai84 and Xiangmai25, as well as the resistant one of Xinyuan958, whereas the lowest attractive activity was observed in the two H. avenae-resistant wheat varieties, Xianmai20 (approximately 12 J2s/plate) and Liangxing66 (approximately 11 J2s/plate). Then Bd21-3, Zhengmai9023 and Heng4399 were selected for further assays as their different attractiveness and resistance to H. avenae, and attractants for H. avenae in their root exudates were characterized to be heat-labile and low-molecular compounds (LM) by behavioral bioassay. Based on these properties of the attractants, a principle of identifying attractants for H. avenae was set up. Then LM of six root exudates from the three plants with and without heating were separated and analyzed by HPLC-MS. Finally, dihydroxyacetone (DHA), methylprednisolone succinate, embelin and diethylpropionin in the root exudates were identified to be putative attractants for H. avenae according to the principle, and the attraction of DHA to H. avenae was validated by behavioral bioassay on agar. Our study enhances the recognition to the orientation mechanism of H. avenae towards wheat roots.


Assuntos
Di-Hidroxiacetona/química , Doenças das Plantas/parasitologia , Raízes de Plantas/química , Triticum/química , Animais , Brachypodium/genética , Brachypodium/parasitologia , Di-Hidroxiacetona/fisiologia , Resistência à Doença/genética , Resistência à Doença/fisiologia , Genótipo , Doenças das Plantas/genética , Raízes de Plantas/genética , Raízes de Plantas/parasitologia , Raízes de Plantas/fisiologia , Triticum/genética , Triticum/parasitologia , Triticum/fisiologia , Tylenchoidea/genética , Tylenchoidea/patogenicidade
6.
Chemosphere ; 259: 127445, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32593005

RESUMO

Iron oxide nanoparticles (nFe2O3)-filled materials have been widely employed in various products and their effects on plants have attracted considerable attention because of their potential release into the environment. Currently, numerous studies reporting the influences of iron-bearing nanoparticles on plants are focused on root or seed exposure. However, plants exposed to atmospheric iron-bearing nanoparticles through the leaves and their impacts on plants are still not well understood. This study focused on the uptake, translocation, and effects of foliar exposure of nFe2O3 on wheat seedlings. Wheat seedlings were foliar applied to various concentrations of nFe2O3 (0, 60 and 180 µg per plant) for 1, 7, 14 or 21 d. Our results demonstrated that after exposure for 21 d, the concentrations of Fe in leaves, stems, and roots were 1100, 280 and 160 µg kg-1, respectively. Scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS), as well as the backscattered electron (BSE) images, revealed the stomatal opening was likely the pathway for nFe2O3 uptake. Analysis of the transfer rate, translocation of Fe from leaves to stems and roots, suggested the involvement of plant Fe regulation processes. Particularly, the antioxidant enzymatic activities and malondialdehyde levels in leaves were modified, which was ascribed to the excessive hydroxyl radical (OH) generated via the Fenton-like reaction mediated by nFe2O3. Finally, the OH facilitated the degradation of chlorophyll, posting a negative impact on the photosynthesis, and thus inhibited the biomass production. These findings are meaningful to understand the fate and physiological effects of atmospheric nFe2O3 in crops.


Assuntos
Compostos Férricos/toxicidade , Nanopartículas/toxicidade , Fotossíntese/efeitos dos fármacos , Triticum/efeitos dos fármacos , Antioxidantes/metabolismo , Transporte Biológico , Biomassa , Clorofila/metabolismo , Compostos Férricos/metabolismo , Ferro/metabolismo , Folhas de Planta/metabolismo , Raízes de Plantas/metabolismo , Plântula/efeitos dos fármacos , Sementes/metabolismo , Triticum/metabolismo , Triticum/fisiologia
7.
PLoS One ; 15(5): e0232974, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32401803

RESUMO

Heat stress along with low water availability at reproductive stage (terminal growth phase of wheat crop) is major contributing factor towards less wheat production in tropics and sub-tropics. Flag leaf plays a pivotal role in assimilate partitioning and stress tolerance of wheat during terminal growth phase. However, limited is known about biochemical response of flag leaf to combined and individual heat and drought stress during terminal growth phase. Therefore, current study investigated combined and individual effect of terminal drought and heat stress on water relations, photosynthetic pigments, osmolytes accumulation and antioxidants defense mechanism in flag leaf of bread wheat. Experimental treatments comprised of control, terminal drought stress alone (50% field capacity during reproductive phase), terminal heat stress alone (wheat grown inside plastic tunnel during reproductive phase) and terminal drought stress + terminal heat stress. Individual and combined imposition of drought and heat stresses significantly (p≤0.05) altered water relations, osmolyte contents, soluble proteins and sugars along with activated antioxidant defensive system in terms of superoxide dismutase (SOD), peroxidase (POD) and ascorbate peroxidase (APX). Turgor potential, POD and APX activities were lowest under individual heat stress; however, these were improved when drought stress was combined with heat stress. It is concluded that combined effect of drought and heat stress was more detrimental than individual stresses. The interactive effect of both stresses was hypo-additive in nature, but for some traits (like turgor potential and APX) effect of one stress neutralized the other. To best of our knowledge, this is the first report on physiological and biochemical response of flag leaf of wheat to combine heat and drought stress. These results will help future studies dealing with improved stress tolerance in wheat. However, detailed studies are needed to fully understand the genetic mechanisms behind these physiological and biochemical changes in flag leaf in response to combined heat and drought stress.


Assuntos
Triticum/crescimento & desenvolvimento , Triticum/fisiologia , Antioxidantes/metabolismo , Pão , Clorofila/metabolismo , Secas , Grão Comestível/crescimento & desenvolvimento , Grão Comestível/fisiologia , Resposta ao Choque Térmico/fisiologia , Fotossíntese , Folhas de Planta/crescimento & desenvolvimento , Folhas de Planta/fisiologia , Água/metabolismo
8.
Artigo em Inglês | MEDLINE | ID: mdl-32466495

RESUMO

Exogenous hormones play an important role in plant growth regulation and stress tolerance. However, little is known about the effect of exogenous abscisic acid (ABA) on wheat seedlings under salt and alkali stresses. Here, a pot experiment of saline and alkaline stresses (0 and 100 mmol/L) in which ABA water solution (0, 50 and 100 µmol/L) was sprayed on wheat seedlings was conducted to study the alleviative effectiveness of ABA on salt and alkali stresses. After spraying ABA (50 µmol·L-1), shoot biomass increased 19.0% and 26.7%, respectively. The Na+ content in shoots reduced from 15-fold and 61.5-fold to 10-fold and 37.3-fold in salt and alkali stresses, compared to controls. In addition, proline and organic acid synthesis in shoots also reduced significantly, but the soluble sugar content increased under alkali stress. A high concentration of ABA (100 µmol·L-1) had no significant effects on biomass and ion content in wheat seedlings under both stresses. In conclusion, foliar application of ABA with moderate concentration could effectively accelerate shoot growth of salt-induced wheat seedlings by adjusting the levels of ions and organic solutes.


Assuntos
Ácido Abscísico , Álcalis , Plântula , Triticum , Ácido Abscísico/farmacologia , Álcalis/toxicidade , Cloreto de Sódio , Estresse Fisiológico , Triticum/fisiologia
9.
PLoS One ; 15(4): e0230855, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32267842

RESUMO

Growing resistant wheat (Triticum aestivum L) varieties is an important strategy for the control of leaf rust, caused by Puccinia triticina Eriks. This study sought to identify the chromosomal location and effects of leaf rust resistance loci in five Canadian spring wheat cultivars. The parents and doubled haploid lines of crosses Carberry/AC Cadillac, Carberry/Vesper, Vesper/Lillian, Vesper/Stettler and Stettler/Red Fife were assessed for leaf rust severity and infection response in field nurseries in Canada near Swift Current, SK from 2013 to 2015, Morden, MB from 2015 to 2017 and Brandon, MB in 2016, and in New Zealand near Lincoln in 2014. The populations were genotyped with the 90K Infinium iSelect assay and quantitative trait loci (QTL) analysis was performed. A high density consensus map generated based on 14 doubled haploid populations and integrating SNP and SSR markers was used to compare QTL identified in different populations. AC Cadillac contributed QTL on chromosomes 2A, 3B and 7B (2 loci), Carberry on 1A, 2B (2 loci), 2D, 4B (2 loci), 5A, 6A, 7A and 7D, Lillian on 4A and 7D, Stettler on 2D and 6B, Vesper on 1B, 1D, 2A, 6B and 7B (2 loci), and Red Fife on 7A and 7B. Lillian contributed to a novel locus QLr.spa-4A, and similarly Carberry at QLr.spa-5A. The discovery of novel leaf rust resistance QTL QLr.spa-4A and QLr.spa-5A, and several others in contemporary Canada Western Red Spring wheat varieties is a tremendous addition to our present knowledge of resistance gene deployment in breeding. Carberry demonstrated substantial stacking of genes which could be supplemented with the genes identified in other cultivars with the expectation of increasing efficacy of resistance to leaf rust and longevity with little risk of linkage drag.


Assuntos
Resistência à Doença/genética , Marcadores Genéticos/genética , Doenças das Plantas/microbiologia , Polimorfismo de Nucleotídeo Único , Locos de Características Quantitativas/genética , Triticum/genética , Triticum/microbiologia , Basidiomycota/fisiologia , Doenças das Plantas/imunologia , Triticum/fisiologia
10.
Ecotoxicol Environ Saf ; 196: 110545, 2020 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-32276162

RESUMO

The relationship between the chemical forms of Cu2+ and Cd2+ adsorbed on the roots of different wheat cultivars and their phytotoxic effects on the plants were investigated. The wheat varieties Dunmaiwang (DMW), Tekang 6 (TK6), Zhongmai895 (ZM895), and Chaojixiaomai (AK68) were used. The zeta potentials of wheat roots, measured by the streaming potential method, were used to characterize root charge properties. Results indicated that the changes in zeta potential at pH 4.01-6.61 were 14.7, 15.53, 13.01, and 12.06 mV for ZM895, AK68, DMW, and TK6, respectively. The negative charge and functional groups on ZM895 and AK68 roots were greater than on DMW and TK6 roots, which led to more exchangeable and complexed Cu2+ and Cd2+ on ZM895 and AK68 roots and increased Cu2+ and Cd2+ toxicity compared to DMW and TK6. Coexisting cations, such as Ca2+, Mg2+, K+, and NH4+, alleviated Cu2+ and Cd2+ toxicity to wheat roots through competition for adsorption sites on the roots, which decreased exchangeable and complexed Cu2+ and Cd2+ on wheat roots. The Ca2+ and Mg2+ were most effective in alleviating heavy metal toxicity and they decreased exchangeable Cu2+ on AK68 roots by 39.14% and 47.82%, and exchangeable Cd2+ by 8.51% and 28.23%, respectively.


Assuntos
Cádmio/toxicidade , Cobre/toxicidade , Poluentes do Solo/toxicidade , Triticum/efeitos dos fármacos , Adsorção , Cádmio/química , Cádmio/farmacocinética , Cátions , Cobre/química , Cobre/farmacocinética , Raízes de Plantas/efeitos dos fármacos , Raízes de Plantas/metabolismo , Raízes de Plantas/fisiologia , Poluentes do Solo/química , Poluentes do Solo/farmacocinética , Triticum/metabolismo , Triticum/fisiologia
11.
J Plant Res ; 133(4): 549-570, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32323039

RESUMO

Salicylic acid (SA) has an important role in drought-tolerance in wheat (Triticum aestivum L.) but its relevance to the salinity-tolerance is not well understood. In the present study, possible roles of SA and salinity responses were examined using two wheat cultivars i.e., drought-tolerant Sakha-69 and drought-sensitive Gemaza-1, exposed to 150 mM NaCl. Parameters were determined for growth i.e. fresh or dry mass (FM, DM), osmotic concentration (OC) of organic/inorganic solute, leaf relative water content (LRWC), photosynthesis pigment content (PPC), and selective antioxidant system (AOS) enzyme/molecule that might be involved in the stress remediation. Sakha-69 exhibited salinity tolerance greater than Gemaza-1 and SA ameliorated their salinity stresses like drought stress, suggesting that a common tolerant mechanism might be involved in the stresses. Salinity decreased root growth by 44-52% more strongly than shoot (36-41%) in FM or those in DM (32-35%). SA ameliorated root growth (40-60%) more efficiently than shoot (6-24%) for DM/FM. These results suggested that salinity and SA might target sensitive roots and hence influencing shoot functions. In fact, salinity reduced PPC by 10-18%, LRWC by 16-28%, and more sensitively, OC of inorganic solutes (K+, Ca2+, Mg2+) in shoot (19-36%) and root (25-59%), except a conspicuous increase in Na+, and SA recovered all the reductions near to control levels. SA and salinity increased additively most parameters for OC of organic solutes (sugars and organic acids) and AOS (glutathione and related enzyme activities), like drought responses. However, SA decreased the Na+ and proline contents and catalase activity in a counteracting manner to salinity. It is concluded from this experiment that SA-mediated tolerance might involve two mechanisms, one specific for minerals in root and the other related to drought/dehydration tolerance governed in the whole module systems.


Assuntos
Antioxidantes , Ácido Salicílico , Triticum , Secas , Salinidade , Triticum/fisiologia , Água
12.
BMC Plant Biol ; 20(1): 96, 2020 Mar 04.
Artigo em Inglês | MEDLINE | ID: mdl-32131734

RESUMO

BACKGROUNDS: The perturbance of chloroplast proteins is a major cause of photosynthesis inhibition under drought stress. The exogenous application of 5-aminolevulinic acid (ALA) mitigates the damage caused by drought stress, protecting plant growth and development, but the regulatory mechanism behind this process remains obscure. RESULTS: Wheat seedlings were drought treated, and the iTRAQ-based proteomic approach was employed to assess the difference in chloroplast protein content caused by exogenous ALA. A total of 9499 peptides, which could be classified into 2442 protein groups, were identified with ≤0.01 FDR. Moreover, the contents of 87 chloroplast proteins was changed by drought stress alone compared to that of the drought-free control, while the contents of 469 was changed by exogenous ALA application under drought stress compared to that of drought stress alone. The Gene Ontology (GO) annotation and Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis results suggested that the ALA pretreatment adjusted some biological pathways, such as metabolic pathways and pathways involved in photosynthesis and ribosomes, to enhance the drought resistance of chloroplasts. Furthermore, the drought-promoted H2O2 accumulation and O2- production in chloroplasts were alleviated by the exogenous pretreatment of ALA, while peroxidase (POD) and glutathione peroxidase (GPX) activities were upregulated, which agreed with the chloroplast proteomic data. We suggested that ALA promoted reactive oxygen species (ROS) scavenging in chloroplasts by regulating enzymatic processes. CONCLUSIONS: Our results from chloroplast proteomics extend the understanding of the mechanisms employed by exogenous ALA to defend against drought stress in wheat.


Assuntos
Proteínas de Cloroplastos/genética , Cloroplastos/metabolismo , Ácidos Levulínicos/metabolismo , Proteoma/genética , Triticum/fisiologia , Proteínas de Cloroplastos/metabolismo , Folhas de Planta/metabolismo , Proteoma/metabolismo , Proteômica , Estresse Fisiológico , Triticum/genética
13.
Gene ; 740: 144514, 2020 May 25.
Artigo em Inglês | MEDLINE | ID: mdl-32112985

RESUMO

As an important transcription factor family, DREB transcription factors play important roles in response to abiotic stresses. In this study, we identified wheat DREB genes at genome-level, and characterized the functions of TaDREB genes. Totally, there are 210 TaDREB genes, which can be divided into 6 subgroups. Some of these genes display tissue-specific expression patterns. Among them, the expression of three TaDREB3 homoeologous genes is induced by abiotic stresses. Meanwhile, as alternatively spliced genes, they generate three isoforms respectively. Transcripts I and II encode DREB proteins, while transcript III does not generate DREB proteins. Transgenic Arabidopsis over-expressing TaDREB3-AI displayed enhanced resistance to drought, salt and heat stresses. The physical indexes and the expression of stress-related genes further verified the functions in response to abiotic stresses. Our results lay a foundation for further study of wheat DREB genes. Especially, our findings indicate that TaDREB3 genes can be used for crop genetic improvement.


Assuntos
Proteínas de Plantas/genética , Fatores de Transcrição/genética , Triticum/genética , Arabidopsis/metabolismo , Arabidopsis/fisiologia , Desidratação , Regulação da Expressão Gênica de Plantas , Resposta ao Choque Térmico , Proteínas de Plantas/metabolismo , Plantas Geneticamente Modificadas , Estresse Salino , Fatores de Transcrição/metabolismo , Triticum/fisiologia
14.
Chemosphere ; 249: 126447, 2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-32208216

RESUMO

Novel alternatives of perfluorooctane sulfonate (PFOS), chlorinated polyfluorinated ether sulfonates (Cl-PFAESs) are increasingly being detected in the aquatic and terrestrial environment. Previous studies mainly focused on aquatic biota; however, the knowledge about the ecotoxicological risk they pose to terrestrial plants was still lacking. In this study, the accumulation of two Cl-PFAES (6:2 and 8:2 Cl-PFAES) and PFOS in wheat seedlings at environmentally relevant levels (50 and 100 µg L-1) was investigated. Concentrations of Cl-PFAESs in the roots were an order of magnitude higher than those in shoots, indicating that they were primarily accumulated in the roots. The values of root and shoot bioconcentration factor was comparable between 6:2 Cl-PFAES and PFOS. However, these indexes of 8:2 Cl-PFAES were 42-91% higher and 70-76% lower than PFOS, respectively. As a result, 6:2 Cl-PFAES had a similar accumulation pattern as PFOS, whereas 8:2 Cl-PFAES was predominantly restricted to the roots, which might be attributed to their hydrophobicity and carbon chain length. In addition, at 250 mg L-1 of Cl-PFAESs, plant biomass and pigment content were 24-30% and 0.4-18%, respectively, which were lower than those of PFOS. As compared with PFOS, Cl-PFAESs induced higher levels of root membrane permeability, reactive oxygen species and malondialdehyde content, as well as reduced the activities of antioxidant enzymes and glutathione content. These suggested the occurrence of a severer oxidative damage and the breakdown of the antioxidant defence system in wheat cells. Therefore, we conclude that Cl-PFAESs might pose a higher potential threat to the environment than PFOS.


Assuntos
Fluorcarbonetos/toxicidade , Poluentes do Solo/toxicidade , Triticum/fisiologia , Alcanossulfonatos , Ácidos Alcanossulfônicos , Éter , Éteres , Fluorcarbonetos/metabolismo , Malondialdeído , Plântula , Poluentes do Solo/metabolismo
15.
Nat Commun ; 11(1): 1243, 2020 03 06.
Artigo em Inglês | MEDLINE | ID: mdl-32144261

RESUMO

Many studies have estimated the adverse effects of climate change on crop yields, however, this literature almost universally assumes a constant geographic distribution of crops in the future. Movement of growing areas to limit exposure to adverse climate conditions has been discussed as a theoretical adaptive response but has not previously been quantified or demonstrated at a global scale. Here, we assess how changes in rainfed crop area have already mediated growing season temperature trends for rainfed maize, wheat, rice, and soybean using spatially-explicit climate and crop area data from 1973 to 2012. Our results suggest that the most damaging impacts of warming on rainfed maize, wheat, and rice have been substantially moderated by the migration of these crops over time and the expansion of irrigation. However, continued migration may incur substantial environmental costs and will depend on socio-economic and political factors in addition to land suitability and climate.


Assuntos
Aclimatação , Mudança Climática , Produção Agrícola/tendências , Produtos Agrícolas/fisiologia , Dispersão Vegetal , Irrigação Agrícola/estatística & dados numéricos , Irrigação Agrícola/tendências , Produção Agrícola/métodos , Produção Agrícola/estatística & dados numéricos , Oryza/fisiologia , Soja/fisiologia , Temperatura , Triticum/fisiologia , Zea mays/fisiologia
16.
J Appl Microbiol ; 129(3): 695-711, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32215987

RESUMO

AIM: The aim of this study was to evaluate the ability of Bacillus methylotrophicus M4-1 to protect winter wheat from the harmful effects of soil salinity and alkalinity. METHODS AND RESULTS: We isolated the halotolerant B. methylotrophicus M4-1. Two representative soils with different salt contents (S1, 213 µs cm-1 ; S2, 786 µs cm-1 ) in the Yellow River delta region of China were selected for experiments. The effects of the M4-1 strain on the typical wheat variety (Jimai 21) in this environment were proven. In S1 soil, the M4-1 strain reduced the wheat rhizosphere soil pH (1·61%) and electrical conductivity (EC) (8·01%) and increased the exchangeable K content (11·14%). The uptake of Mg2+ (20·73%) by wheat roots and K+ (8·84%) by leaves was increased, and the content of Na+ (23·62%) in leaves was reduced. In S2 soil, the M4-1 strain was able to reduce soil EC (2·56%) and increase exchangeable K (11·20%) content. The absorption of K+ (13·28%) in wheat leaves was increased, and the content of Na+ (12·41%) in roots was decreased. Total N and organic matter contents in rhizosphere soil were significantly positively correlated with wheat growth and salt tolerance, whereas EC showed a significant negative correlation. CONCLUSIONS: M4-1 attenuates salt stress injury in wheat under both low and high salt stress. SIGNIFICANCE AND IMPACT OF THE STUDY: We demonstrated the efficacy and value of plant growth-promoting rhizobacteria addition to protect winter wheat against salt stress and improve crop yield. We also elucidated the physicochemical and biochemical interactions among M4-1, the rhizosphere and the host plant.


Assuntos
Bacillus/fisiologia , Estresse Salino , Triticum/microbiologia , Triticum/fisiologia , China , Folhas de Planta/metabolismo , Folhas de Planta/microbiologia , Raízes de Plantas/metabolismo , Raízes de Plantas/microbiologia , Rizosfera , Salinidade , Tolerância ao Sal , Solo/química , Microbiologia do Solo
17.
Artigo em Inglês | MEDLINE | ID: mdl-32114414

RESUMO

Heat shock transcription factors (Hsfs) play an important role in regulating heat stress response in plants. Our previous study found that there were 82 non-redundant Hsfs in wheat, 18 of which belonged to subclass A2. In this study, we cloned an A2 member, TaHsfA2-1, which encoded a protein of 346 amino acid residues in wheat. The fusion protein TaHsfA2-1-GFP was localized in the nucleus under normal growth conditions. TaHsfA2-1 was expressed in nearly all the measured tissues, most highly in mature leaves. The expression level of TaHsfA2-1 can be enhanced by heat stress, PEG stress, and signal molecules such as H2O2 and SA. Yeast cells transformed with TaHsfA2-1 improved thermotolerance compared to those with the empty vector. TaHsfA2-1-overexpressing Arabidopsis displayed a better growth state with more green leaves than wild-type seedlings after heat stress. Accordingly, the chlorophyll content and survival rate in the transgenic lines were higher than in the wild type, and relative conductivity in the transgenic lines was lower than in the wild type. Further research found that TaHsfA2-1-overexpressing Arabidopsis up-regulated the expression of some heat shock protein genes (Hsps) compared to wild type after heat stress. These results suggested that TaHsfA2-1 is a new gene that improves thermotolerance in plants by mediating the expression of Hsps. A functional gene was provided for molecular breeding in the subsequent research.


Assuntos
Regulação da Expressão Gênica de Plantas/fisiologia , Fatores de Transcrição de Choque Térmico/genética , Proteínas de Plantas/genética , Termotolerância/genética , Triticum/fisiologia , Sequência de Aminoácidos , Arabidopsis/genética , Arabidopsis/fisiologia , Proteínas de Arabidopsis/genética , Proteínas de Arabidopsis/metabolismo , Fatores de Transcrição de Choque Térmico/química , Fatores de Transcrição de Choque Térmico/metabolismo , Filogenia , Proteínas de Plantas/metabolismo , Plantas Geneticamente Modificadas/genética , Plantas Geneticamente Modificadas/fisiologia , Plântula/genética , Plântula/fisiologia , Alinhamento de Sequência , Triticum/genética
18.
BMC Plant Biol ; 20(1): 50, 2020 Jan 31.
Artigo em Inglês | MEDLINE | ID: mdl-32005165

RESUMO

BACKGROUND: Many studies in Arabidopsis and rice have demonstrated that HD-Zip transcription factors play important roles in plant development and responses to abiotic stresses. Although common wheat (Triticum aestivum L.) is one of the most widely cultivated and consumed food crops in the world, the function of the HD-Zip proteins in wheat is still largely unknown. RESULTS: To explore the potential biological functions of HD-Zip genes in wheat, we performed a bioinformatics and gene expression analysis of the HD-Zip family. We identified 113 HD-Zip members from wheat and classified them into four subfamilies (I-IV) based on phylogenic analysis against proteins from Arabidopsis, rice, and maize. Most HD-Zip genes are represented by two to three homeoalleles in wheat, which are named as TaHDZX_ZA, TaHDZX_ZB, or TaHDZX_ZD, where X denotes the gene number and Z the wheat chromosome on which it is located. TaHDZs in the same subfamily have similar protein motifs and intron/exon structures. The expression profiles of TaHDZ genes were analysed in different tissues, at different stages of vegetative growth, during seed development, and under drought stress. We found that most TaHDZ genes, especially those in subfamilies I and II, were induced by drought stress, suggesting the potential importance of subfamily I and II TaHDZ members in the responses to abiotic stress. Compared with wild-type (WT) plants, transgenic Arabidopsis plants overexpressing TaHDZ5-6A displayed enhanced drought tolerance, lower water loss rates, higher survival rates, and higher proline content under drought conditions. Additionally, the transcriptome analysis identified a number of differentially expressed genes between 35S::TaHDZ5-6A transgenic and wild-type plants, many of which are involved in stress response. CONCLUSIONS: Our results will facilitate further functional analysis of wheat HD-Zip genes, and also indicate that TaHDZ5-6A may participate in regulating the plant response to drought stress. Our experiments show that TaHDZ5-6A holds great potential for genetic improvement of abiotic stress tolerance in crops.


Assuntos
Secas , Família Multigênica , Proteínas de Plantas/genética , Fatores de Transcrição/genética , Triticum/fisiologia , Arabidopsis/genética , Arabidopsis/fisiologia , Proteínas de Plantas/metabolismo , Plantas Geneticamente Modificadas/genética , Plantas Geneticamente Modificadas/metabolismo , Fatores de Transcrição/metabolismo , Triticum/genética
19.
Sci Rep ; 10(1): 3305, 2020 02 24.
Artigo em Inglês | MEDLINE | ID: mdl-32094371

RESUMO

Excessive nitrogen (N) input and irrigation exacerbate N leaching in winter wheat production in the North China Plain (NCP). To explore the optimal N for better N remobilization and higher N utilization of wheat under water-saving irrigation will be conductive to less environmental contamination. A field experiment was conducted at 300 (N300), 240 (N240), 180 (N180), and 0 (N0) kg N ha-1 of N application under supplemental irrigation (SI) that brought the relative soil water content (RSWC) to 70% at jointing and 65% at anthesis. Compared with N0, N180 improved the free amino acid content in the flag leaf and grain after anthesis, dry matter and plant N accumulation at maturity, N translocation amount of vegetable organs and its contribution to grain from anthesis to maturity. Compared to N240 and N300, N180 increased the N translocation efficiency of vegetable organs, and reduced the soil NO3-N residue in the 60-180 cm soil layer, which contributing to no significant reduction in grain yield and grain protein yield, but higher grain N recovery efficiency (GREN), N recovery efficiency (REN), and N partial factor productivity (PFPN). Positive relationships were found between leaf N translocation efficiency and grain yield, grain protein yield, PFPN, GREN, and REN. Therefore, N180 is appropriate to obtain a steady grain yield over 7.5 t ha-1 for at least 2 years under SI based on RSWC in the NCP.


Assuntos
Irrigação Agrícola , Nitrogênio/farmacologia , Triticum/fisiologia , Aminoácidos/análise , Biomassa , China , Nitratos/metabolismo , Especificidade de Órgãos/efeitos dos fármacos , Folhas de Planta/química , Solo/química , Triticum/efeitos dos fármacos , Triticum/crescimento & desenvolvimento
20.
Environ Pollut ; 259: 113939, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-32023796

RESUMO

A field study was conducted to understand the physiological responses, yield and grain quality of an old (HUW234) and a modern (HD3118) wheat cultivar exposed to elevated ozone (O3). The cultivars were grown under ambient O3 (NF) and ambient +20 ppb O3 (NF+) conditions using open-top chambers (OTCs). The comparative study of an old and a modern cultivar showed variable physiological responses under elevated O3 exposure. Elevated O3 in old cultivar caused high reductions in Rubisco activity (Vcmax) and electron transport rate (J) compared to modern cultivar with simultaneous reductions in the rate of photosynthesis and chlorophyll fluorescence. In modern cultivar, high stomatal density and conductance caused higher O3 uptake thereby triggering more damage to the adjacent stomatal cells and photosynthetic pigments coupled with reductions in photosynthetic rate and photosynthetic nitrogen use efficiency (PNUE). Modern cultivar also showed relatively high reduction in grain yield compared to old one under NF + treatment. Furthermore, grain quality traits (such as starch, protein and amino acids) of modern cultivar were better than old cultivar under ambient O3, but showed more deterioration under NF + treatment. Results thus indicated that modern cultivar is relatively more susceptible to O3 and showed more negative impacts on plant performance, yield and quality of grains compared to old cultivar.


Assuntos
Ozônio , Triticum/fisiologia , Clorofila , Grão Comestível , Fotossíntese , Folhas de Planta
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