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1.
Mar Pollut Bull ; 167: 112290, 2021 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-33799151

RESUMO

The Mediterranean coastal area of the Nile Delta is socio-economically vital, however, it is under significant environmental stress due to pollution from land-based activities. The study investigates the temporal variations of trace metals to assess the development of the anthropogenic pollution status in the coastal sediments. The average concentrations, the enrichment factor, and the geoaccumulation index revealed that Cr, V, Ni, and Co are pollutants of concern. Trace metals are particularly accumulating in the sediments further offshore and in the middle and eastern sectors of the Nile Delta coast. The temporal patterns of the pollution load index (PLI) along the Nile Delta coastal indicate that pollution hotspots are increasingly exposed to trace metals pollution over time. This is linked to discharges from anthropogenic land-based activities and controlled by sedimentological factors. A conceptual model for the accumulation of trace metals in sediments is proposed based on this study.


Assuntos
Metais Pesados , Oligoelementos , Poluentes Químicos da Água , Monitoramento Ambiental , Poluição Ambiental , Sedimentos Geológicos , Metais Pesados/análise , Poluentes Químicos da Água/análise
2.
Plant Sci ; 302: 110699, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-33288012

RESUMO

Abscisic acid-responsive element (ABRE)-binding factors (ABFs) are important transcription factors involved in various physiological processes in plants. Stomata are micro channels for water and gas exchange of plants. Previous researches have demonstrated that ABFs can modulate the stomatal development in some plants. However, little is known about stomata-related functions of ABFs in carrots. In our study, DcABF3, a gene encoding for ABF transcription factor, was isolated from carrot. The open reading frame of DcABF3 was 1329 bp, encoding 442 amino acids. Expression profiles of DcABF3 indicated that DcABF3 can respond to drought, salt or ABA treatment in carrots. Overexpressing DcABF3 in Arabidopsis led to the increase of stomatal density which caused severe water loss. Expression assay indicated that overexpression of DcABF3 caused high expression of stomatal development-related transcription factor genes, SPCH, FAMA, MUTE and SCRMs. Increased antioxidant enzyme activities and higher expression levels of stress-related genes were also found in transgenic lines after water deficit treatment. Changes in expression of ABA synthesis-related genes and AtABIs indicated the potential role of DcABF3 in ABA signaling pathway. Under the treatment of exogenous ABA, DcABF3-overexpression Arabidopsis seedlings exhibited increased root length and germination rate. Our findings demonstrated that heterologous overexpression of DcABF3 positively affected stomatal development and also reduced ABA sensitivity in transgenic Arabidopsis.


Assuntos
Ácido Abscísico/metabolismo , Daucus carota/genética , Reguladores de Crescimento de Plantas/metabolismo , Proteínas de Plantas/fisiologia , Estômatos de Plantas/fisiologia , Fatores de Transcrição/fisiologia , Arabidopsis/genética , Arabidopsis/metabolismo , Arabidopsis/fisiologia , Clonagem Molecular , Daucus carota/metabolismo , Daucus carota/fisiologia , Desidratação , Proteínas de Plantas/genética , Plantas Geneticamente Modificadas/genética , Plantas Geneticamente Modificadas/metabolismo , Plantas Geneticamente Modificadas/fisiologia , Reação em Cadeia da Polimerase em Tempo Real , Fatores de Transcrição/genética , Transcriptoma
3.
PeerJ ; 8: e10492, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33354430

RESUMO

Carrot is an important root vegetable crop abundant in bioactive compounds including carotenoids, vitamins, and dietary fibers. Carrot intake and its products are gradually growing owing to its high antioxidant activity. Auxins are a class of plant hormones that control many processes of plant growth and development. Yet, the effects of exogenous application of auxin on lignin biosynthesis and gene expression profiles of lignin-related genes in carrot taproot are still unclear. In order to investigate the effect of exogenous indole-3-butyric acid (IBA) on lignin-related gene profiles, lignin accumulation, anatomical structures and morphological characteristics in carrot taproots, carrots were treated with different concentrations of IBA (0, 50, 100, and 150 µM). The results showed that IBA application significantly improved the growth parameters of carrot. The 100 or 150 µM IBA treatment increased the number and area of xylem vessels, whereas transcript levels of lignin-related genes were restricted, resulting in a decline in lignin content in carrot taproots. The results indicate that taproot development and lignin accumulation may be influenced by the auxin levels within carrot plants.

4.
Protoplasma ; 257(6): 1507-1517, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32577829

RESUMO

Carrot is a root crop consumed worldwide and has great nutritional qualities. It is considered as one of the ten most important vegetable crops. Cytokinins are an essential class of the plant hormones that regulate many processes of plant growth. Till now, the effects of cytokinin, BAP, on lignin biosynthesis and related gene expression profiles in carrot taproot is unclear. In order to investigate the effect of applied BAP on lignin-related gene expression profiles, lignin accumulation, anatomical structures, and morphological characters in carrot taproots. Carrot roots were treated with different concentrations of BAP (0, 10, 20, and 30 mg L-1). The results showed that the application of BAP significantly increased plant length, shoot fresh weight, root fresh weight, and taproot diameter. In addition, BAP at 20 mg L-1 or 30 mg L-1 enhanced the average number of petioles. BAP treatment led to increased number and width of xylem vessels. The parenchyma cell numbers of pith were significantly induced in taproots treated with the BAP at a concentration of 30 mg L-1. BAP significantly upregulated most of the expression levels of lignin biosynthesis genes, caused elevated lignin accumulation in carrot taproots. Our results indicate that BAP may play important roles in growth development and lignification in carrot taproots. Our results provide a valuable database for more studies, which may focus on the regulation of root lignification via controlling cytokinin levels in carrot taproots.


Assuntos
Citocininas/química , Daucus carota/química , Perfilação da Expressão Gênica/métodos , Lignina/síntese química
5.
Protoplasma ; 257(3): 949-963, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-31982943

RESUMO

Carotenoids are a group of natural pigments that are widely distributed in various plants. Carrots are plants rich in carotenoids and have fleshy roots with different colors. Carotenoid accumulation is a complex regulatory process with important guiding significance for carrot production. In this work, three carrot cultivars with different taproot colors, Hongxinqicun (orange), Benhongjinshi (red), and Tianzi (purple) were chosen as experimental materials to explore the molecular mechanism of carotenoid accumulation in carrot. Results showed that the three carotenoids, namely, α-carotene, ß-carotene, and lutein, had accumulated in orange carrot cultivar Hongxinqicun. Lycopene was only detected in the taproots of Benhongjinshi. Lutein was the main carotenoid in Tianzi. Comparison of the carotenoid contents in different tissues of carrot showed that leaf blade was the tissue with the highest carotenoid accumulation. Expression analysis of carotenoid biosynthesis genes and its correlation with carotenoid accumulation confirmed the regulatory role of structural genes in carrots. The high expression of five lycopene synthesis-related genes, DcPSY2, DcPDS, DcZDS1, DcCRT1, DcCRT2, and low expression of DcLCYE may result in the lycopene accumulation in Benhongjinshi. However, the function of certain genes, such as DcPSY1 that was lowly expressed in red carrot, requires further investigation. Our results provided potential insights into the mechanism of carotenoid accumulation in three carrot cultivars with different taproot colors.


Assuntos
Carotenoides/metabolismo , Daucus carota/química , Regulação da Expressão Gênica de Plantas/genética , Cor
7.
Hortic Res ; 6: 69, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31231527

RESUMO

Carrots (Daucus carota L.), among the most important root vegetables in the Apiaceae family, are cultivated worldwide. The storage root is widely utilized due to its richness in carotenoids, anthocyanins, dietary fiber, vitamins and other nutrients. Carrot extracts, which serve as sources of antioxidants, have important functions in preventing many diseases. The biosynthesis, metabolism, and medicinal properties of carotenoids in carrots have been widely studied. Research on hormone regulation in the growth and development of carrots has also been widely performed. Recently, with the development of high-throughput sequencing technology, many efficient tools have been adopted in carrot research. A large amount of sequence data has been produced and applied to improve carrot breeding. A genome editing system based on CRISPR/Cas9 was also constructed for carrot research. In this review, we will briefly summarize the origins, genetic breeding, resistance breeding, genome editing, omics research, hormone regulation, and nutritional composition of carrots. Perspectives about future research work on carrots are also briefly provided.

8.
Plant Sci ; 277: 110-120, 2018 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-30466576

RESUMO

Brassinosteroid (BR) is a predominant plant hormone in regulating cell elongation and cell size. BR-deficient mutants display reduced plant growth and dwarfism in Arabidopsis and rice. In carrot, BRs promote petiole elongation, but its underlying mechanism involving exogenous BR remains unknown. Here, weighted gene co-expression network analysis and promoter region analysis were adopted to identify the potential genes that interacted with DcBZR1/BES1. Bioactive gibberellin (GA) level and cellulose deposition were also determined in the control and treated plants. Quantitative real-time PCR was performed to detect the expression profiles of GA biosynthesis-related genes, GA signaling genes, and cellulose synthase genes. Bioactive GA level and cellulose deposition were upregulated after the petioles were treated with 24-epibrassinolide (24-EBL). The most putative DcBZR1/BES1 genes were clustered in yellow module. The expression level of DCAR_009411 (a GA5-like gene) was significantly induced after 3 h of treatment. The expression levels of DCAR_019754 and DCAR_013973 (CESA-like genes) were also significantly induced after 3 h of 24-EBL treatment. Our results suggested that the effect of BR on carrot petiole growth was quick. These results also provided potential insights into the mechanism by which BRs modulate GA and cellulose synthesis to promote cell elongation in carrot petioles.


Assuntos
Brassinosteroides/farmacologia , Celulose/metabolismo , Daucus carota/efeitos dos fármacos , Giberelinas/metabolismo , Daucus carota/genética , Regulação da Expressão Gênica de Plantas/efeitos dos fármacos , Regulação da Expressão Gênica de Plantas/genética , Transdução de Sinais/efeitos dos fármacos , Transdução de Sinais/genética , Esteroides Heterocíclicos/farmacologia
9.
J Agric Food Chem ; 66(30): 8209-8220, 2018 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-29980166

RESUMO

In our study, isobaric tags for relative and absolute quantification (iTRAQ) was conducted to determine the significantly changed proteins in the fleshy roots of carrots under different carbon dioxide (CO2) treatments. A total of 1523 proteins were identified, of which 257 were differentially expressed proteins (DEPs). On the basis of annotation analysis, the DEPs were identified to be involved in energy metabolism, carbohydrate metabolism, and some other metabolic processes. DcC4H and DcPER, two lignin-related proteins, were identified from the DEPs. Under elevated CO2 stress, both carrot lignin content and the expression profiles of lignin biosynthesis genes changed significantly. The protein-protein interactions among lignin-related enzymes proved the importance of DcC4H and DcPER. The results of our study provided potential new insights into the molecular mechanism of lignin content changes in carrot roots under elevated CO2 stress.


Assuntos
Dióxido de Carbono/metabolismo , Daucus carota/metabolismo , Lignina/análise , Dióxido de Carbono/análise , Daucus carota/química , Daucus carota/genética , Perfilação da Expressão Gênica , Regulação da Expressão Gênica de Plantas , Lignina/metabolismo , Raízes de Plantas/química , Raízes de Plantas/genética , Raízes de Plantas/metabolismo
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