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Ascorbic acid (AsA) is a crucial antioxidant in vegetables. Celery (Apium graveolens L.) is a vegetable of Apiaceae and is rich in AsA. Till now, the effects of different storage conditions on celery morphological characteristics, anatomical features, and antioxidant accumulation are unclear. Here, the celery cvs. 'Sijixiaoxiangqin' and 'Liuhehuangxinqin' were selected as experimental materials, and the two celery plants grown for 65 days were harvested from soils and stored in light at room temperature (25 °C), darkness at low temperature (4 °C), and darkness at room temperature (25 °C) for 0, 6, 24, 30, 48, and 54 h, respectively. The results showed that celery in darkness had better water retention capacity than celery in light. Morphological changes in celery mesophyll, leaf veins, and petioles were the least in darkness at low temperature (4 °C). The weight loss rate and wilting degree in darkness at low temperature (4 °C) were the lowest, and the AsA content remained at a high level. The expression patterns of GDP-d-mannose pyrophosphorylase (AgGMP) and l-galactose dehydrogenase (AgGalDH) were similar to the change of AsA content. The results indicated that low temperature and dark was the optimized storage condition for 'Sijixiaoxiangqin' and 'Liuhehuangxinqin' celery. AgGMP and AgGalDH genes may play an important role in the accumulation of AsA in celery. This paper will provide potential references for prolonging the shelf life of celery and other horticultural crops. [ABSTRACT FROM AUTHOR]

BRs (brassinosteroids), an endogenous hormone in plants, regulate cellulose accumulation, cell elongation and plant growth. Propiconazole (PCZ) is an effective inhibitor of BR biosynthesis. DCB (2,6-Dichlorobenzonitrile) can inhibit the synthesis of cellulose and affects the chemical composition of cell walls. Celery is one important leafy vegetable of the Apiaceae family with rich dietary fiber (including cellulose). The petioles length, leaf blades number and cellulose content determine the yield and quality of celery. The family members of AgCESAs are related to cellulose biosynthesis in higher plants. To investigate the effects of BRs, PCZ and DCB on the growth of celery, celery cv. 'Jinnan Shiqin' plants were treated with 24-epibrassinolide (24-EBL, most active form of BRs), PCZ and DCB, respectively. The results showed that exogenous application of BRs up-regulated the expression of AgCESAs genes and accumulated more cellulose in celery. The length of petioles and number of leaf blades in celery plants applied with exogenous BRs (1.24 × 10−6 mol/L 24-EBL) were increased 2.16 and 1.37 times of that in the control. The addition of PCZ inhibited the effects of exogenous BRs application. The lengths of hypocotyl and hypocotyl cells of celery plants treated with BRs were longer than that of the control. Under DCB treatments, the expression levels of AgCESAs genes in celery petioles and leaf blades were down-regulated compared with the control, and the celery plants showed decreased cellulose content, shorter petiole length and fewer leaf blades. The length of hypocotyl and hypocotyl cells of celery treated with DCB were shorter than that of the control. This study provided a reference for the functions of BRs and DCB on the growth and development of celery. [ABSTRACT FROM AUTHOR]

Celery (Apium graveolens L.) is a leafy vegetable of Apiaceae, which is greatly popular because of its rich nutrients. Lutein and β-carotene are two important carotenoids. Lycopene epsilon cyclase (LCY-ε) is a key branch point enzyme in the carotenoid biosynthetic pathway. In this study, we cloned the AgLCY-ε gene from celery and overexpressed it in Arabidopsis. The results showed that both lutein and β-carotene accumulation increased significantly in transgenic Arabidopsis hosting AgLCY-ε gene, compared with wild type (WT) plants. The transcription levels of AtPSY and AtCRTISO genes involved in carotenoids biosynthesis also increased in transgenic lines. One-month-old transgenic Arabidopsis seedlings were treated with 200 mM NaCl. The malondialdehyde (MDA) content in transgenic Arabidopsis plants after salt treatment was significantly lower, and the activities of the two antioxidant enzymes, superoxide dismutase (SOD) and peroxidase (POD), were significantly increased than that of WT plants. Overexpression of AgLCY-ε gene showed increased lutein and β-carotene accumulations, and enhanced salt tolerance in transgenic plants. • UPLC system was used to determine the lutein and β-carotene contents. • Lutein and β-carotene contents were increased in Arabidopsis hosting celery AgLCY-ε gene. • Overexpression of AgLCY-ε enhanced the salt tolerance in Arabidopsis. [ABSTRACT FROM AUTHOR]

White celery (Apium graveolens L.), a variety of common celery, is an important leafy vegetable in the Apiaceae family and is famous for its nutritional value. However, limited work has been devoted to quality formation and regulation in white celery. In this study, four white celery varieties, 'Xuebaiqincai', 'Saixue', 'Baiganshiqin' and 'Ruixue', were selected and analyzed for the comparison of ascorbic acid (AsA) and lignin levels, which are two important quality evaluation indicators in celery. The expression levels of the genes involved in AsA and lignin metabolic pathways were also detected. In the leaf blades, the AsA content was highest in 'Xuebaiqincai' compared with other varieties, whereas the most abundant AsA levels in the petioles were observed in 'Baiganshiqin' and 'Ruixue'. The expression levels of AsA-related genes varied among the studied varieties. The highest level was detected in 'Xuebaiqincai', whereas other varieties exhibited relatively lower levels. The lignin content in the leaf blades was lower than that in the petioles. Correspondingly, the transcript profiles of genes involved in lignin biosynthesis were in accordance with the different levels in the petioles and blades. The results of this study provide potentially useful information for white celery breeding aimed at quality improvement and regulation. [ABSTRACT FROM AUTHOR]

Increasing the level of AsA and maintaining proper lignin content will improve the quality of celery (Apium graveolens L.). However, the study on the regulation mechanism of genes related to AsA and lignin metabolism in celery was limited, especially in yellow celery. In this study, the accumulation of AsA and lignin and the expression profiles of related-genes were detected in three kinds of yellow celery. The results showed that the content of AsA was higher in the leaf blades of 'Huangtaiji' and the petioles of 'Jinhuangqincai'. The content of lignin was the highest in 'Jinhuangqincai' leaves, followed by 'Liuhehuangxinqin' and 'Huangtaiji'. The expression levels of AgAO (r = −0.032) and AgDHAR1 (r = −0.193) genes involved in AsA recycling and degradation showed negatively correlated with AsA content. AgCCoAOMT (r = 0.692) and AgF5 H (r = 0.733) genes expression were positively correlated with lignin content, while the expression of AgCAD (r = −0.694) and AgC3ʹH (r = −0.722) genes were negatively correlated with lignin content. Our current work provided potential theoretical basis for effectively changing accumulation of AsA and lignin by genetic engineering in celery. [ABSTRACT FROM AUTHOR]

Ascorbate is an antioxidant in plants. Its content is an important index to evaluate the nutritional quality of celery. In higher plant, ascorbate accumulation is effected by CO2 concentration. To study the effects of elevated CO2 (1000 µmol mol−1) on ascorbate accumulation in celery, ascorbate contents and the transcript levels of genes related to ascorbate metabolism in the leaves (leaf blade and petiole) were detected. The results of current study showed that the ascorbate and total ascorbate levels increased during all the treated stages in celery petioles, and they were 1.09–3.91 fold of the control. In leaf blades, the ascorbate contents exhibited a lower level (96.12% and 90.46% of the control) in treatments at 2 and 4 days, and then increased to 1.04 and 1.27 fold of the control in treatments at 6 and 8 days, respectively. Elevated CO2 altered the expression profiles of ascorbate-related genes and the activities of corresponding enzymes. Expression levels of the genes, AgPGI2, AgGMP, AgPMI, AgGalDH, AgGalLDH, GalUR, AgDHAR1, AgAPX1, and AgAO, in the leaf blades corresponded well to the change in ascorbate contents. At 6 days of treatment, the relative expression levels of AgPGI2, AgPMI, AgGGP1, AgGGP2, AgGalUR, AgMDHAR, AgDHAR1, and AgAPX1 in leaf blades increased, and were 4.41, 2.39, 4.65, 3.64, 3.11, 4.53, 4.59, and 3.86 times higher than that of the control. Increased ascorbate accumulation in celery leaves under elevated CO2 treatments might be also related to the change in SOD, POD, and CAT activities, as well as GSH content. These results will enhance our understanding on the effects of elevated CO2 on ascorbate accumulation and potential molecular mechanism regulating ascorbate metabolism in celery. [ABSTRACT FROM AUTHOR]

Celery (Apium graveolens L.) is a vegetable crop in the Apiaceae family that is widely cultivated and consumed because it contains necessary nutrients and multiple biologically active ingredients, such as apigenin and terpenoids. Here, we report the genome sequence of celery based on the use of HiSeq 2000 sequencing technology to obtain 600.8 Gb of data, achieving ~189-fold genome coverage, from 68 sequencing libraries with different insert sizes ranging from 180 bp to 10 kb in length. The assembled genome has a total sequence length of 2.21 Gb and consists of 34,277 predicted genes. Repetitive DNA sequences represent 68.88% of the genome sequences, and LTR retrotransposons are the main components of the repetitive sequences. Evolutionary analysis showed that a recent whole-genome duplication event may have occurred in celery, which could have contributed to its large genome size. The genome sequence of celery allowed us to identify agronomically important genes involved in disease resistance, flavonoid biosynthesis, terpenoid metabolism, and other important cellular processes. The comparative analysis of apigenin biosynthesis genes among species might explain the high apigenin content of celery. The whole-genome sequences of celery have been deposited at CeleryDB (http://apiaceae.njau.edu.cn/celerydb). The availability of the celery genome data advances our knowledge of the genetic evolution of celery and will contribute to further biological research and breeding in celery as well as other Apiaceae plants. [ABSTRACT FROM AUTHOR]

Celery (Apium graveolens L.) is one of the most important vegetables in the Apiaceae family, rich in nutrients and widely grown around the world. bZIP transcription factors family plays an important role in the transcription regulation of plant growth and development, as well as adaptation to the external environment. In this paper, 62 bZIP family transcription factors were screened and identified based on the whole genome sequence of celery. The bZIP proteins of celery and Arabidopsis thaliana were divided into 10 subfamilies according to the phylogenetic tree. Phylogenetic and evolutionary analysis showed that the number of bZIP family members gradually expanded from lower plants to higher plants during the long evolution process. Based on the homology of celery and A. thaliana bZIP genes, the interaction network between celery bZIP transcription factors and other proteins in the genome was constructed, and the correlation data of protein interaction were also obtained. The expression profiles of 12 selected AgbZIP genes were detected and analyzed under abiotic stress treatments and different tissues using RT-qPCR. The results showed that AgbZIP can respond to high temperature, low temperature, drought, and high salt stress. [ABSTRACT FROM AUTHOR]

Gibberellins (GAs), as one of the important hormones in regulating the growth and development of higher plants, can significantly promote cell elongation and expansion. Celery is a widely grown leafy vegetable crop with rich nutritional value. However, the effect of gibberellins on celery leaves is unclear. In this paper, the celery variety "Jinnan Shiqin" plants were treated with gibberellic acid (GA3) and paclobutrazol (PBZ, a gibberellin inhibitor). Our results showed that GA3 treatment promoted the growth of celery leaves and caused lignification of celery leaf tissue. In addition, the transcript levels of genes associated with gibberellins, auxin, cytokinins, ethylene, jasmonic acid, abscisic acid, and brassinolide were altered in response to increased or decreased exogenous gibberellins or inhibitor. GA3 may regulate celery growth by interacting with other hormones through crosstalk mechanisms. This study provided a reference for further study of the regulation mechanism of gibberellins metabolism, and exerted effects on understanding the role of gibberellins in the growth and development of celery. [ABSTRACT FROM AUTHOR]

Gibberellin (GA) is a phytohormone of a biguanide compound that plays an important role throughout the life cycle of a plant. Lignin, a phenylalanine-derived aromatic polymer, can enhance the water transport function and structural resistance of cell walls. This function is also the core on biology of higher terrestrial plants. An appropriate lignin level is important to the quality of leafy vegetables, such as celery. The relationship between gibberellin levels and the occurrence of lignification has not been reported in celery. In this study, the leaf blades and petioles of celery cultivars 'Liuhe Huangxinqin' and 'Jinnan Shiqin' were used as materials, and different concentrations of exogenous gibberellin were applied to analyze the growth and lignin distribution of leaf blades and petioles. It was found that gibberellin treatment could influence the lignin content in celery leaves. Autofluorescence analysis under ultraviolet (UV) excitation showed that gibberellin treatment caused lignification of celery leaf tissue. The expression profiles of 12 genes related to lignin synthesis changed with the increase of gibberellin concentration. Our results showed that gibberellin played a significant role in the accumulation of lignin in the development of celery leaves. This provides a basis for further study on the regulation of lignin metabolism in plants and exerts a vital part in the application of plant growth regulators to production. [ABSTRACT FROM AUTHOR]

Carbon dioxide (CO 2 ) is an important regulator of plant growth and development, and its proportion in the atmosphere continues to rise now. Lignin is one of the major secondary products in plants with vital biological functions. However, the relationship between CO 2 level and xylogenesis in celery is still unknown. In order to investigate the effects of increasing CO 2 concentration on lignin accumulation in celery, ‘Jinnanshiqin’ were exposed to two CO 2 applications, 400 (e 0 ) and 1000 μmol mol −1 (e 1 ), respectively. Plant morphology and lignin distribution in celery plants treated with elevated CO 2 did not change significantly. There was an upward trend on lignin content in celery leaves, and the transcript abundance of 12 genes involved in lignin metabolism has altered in response to elevated CO 2 . The effects of high level of CO 2 on different tissues were different. Our works confirmed that CO 2 may play an important role in lignin accumulation in celery leaves. The current study will offer new evidence to understand the regulation mechanism of lignin biosynthesis under elevated CO 2 and provide a reference to improve celery quality by adjusting the growth environment. [ABSTRACT FROM AUTHOR]

Main conclusion: This study showed that a galactosyltransferase, AgUCGalT1, is involved in anthocyanin galactosylation in purple celery.Celery is a well-known vegetable because of its rich nutrients, low calories, and medicinal values. Its petioles and leaf blades are the main organs acting as nutrient sources. UDP-galactose: cyanidin 3-O-galactosyltransferase can transfer the galactosyl moiety from UDP-galactose to the 3-O-position of cyanidin through glycosylation. This process enhances the stability and water solubility of anthocyanins. In the present study, LC-MS data indicated that abundant cyanidin-based anthocyanins accumulated in the petioles of purple celery (‘Nanxuan liuhe purple celery’). A gene encoding UDP-galactose: cyanidin 3-O-galactosyltransferase, namely AgUCGalT1, was isolated from purple celery and expressed in Escherichia coli BL21 (DE3). Sequence alignments revealed that the AgUCGalT1 protein contained a highly conserved putative secondary plant glycosyltransferase (PSPG) motif. The glycosylation product catalyzed by AgUCGalT1 was detected using UPLC equipment. The recombinant AgUCGalT1 had an optimal enzyme activity at 35 °C and pH 8.0, and showed highest enzyme activity toward cyanidin among the enzyme activities involving other substances, namely, peonidin, quercetin, and kaempferol. The expression levels of AgUCGalT1 were positively correlated with the total anthocyanin contents in purple and non-purple celery varieties. Crude enzymes extracted from purple celery exhibited glycosylation ability, whereas crude enzymes obtained from non-purple celery did not have this ability. This work provided evidence as a basis for investigations on the function of AgUCGalT1 in anthocyanin glycosylation in purple celery. [ABSTRACT FROM AUTHOR]

Celery (Apium graveolens L.) is a plant belonging to the Apiaceae family, and a popular vegetable worldwide because of its abundant nutrients and various medical functions. Although extensive genetic and molecular biological studies have been conducted on celery, its genomic data remain unclear. Given the significance of celery and the growing demand for its genomic data, the whole genome of 'Q2-JN11' celery (a highly inbred line obtained by artificial selfing of 'Jinnan Shiqin') was sequenced using HiSeq 2000 sequencing technology. For the convenience of researchers to study celery, an online database of the whole-genome sequences of celery, CeleryDB, was constructed. The sequences of the whole genome, nucleotide sequences of the predicted genes and amino acid sequences of the predicted proteins are available online on CeleryDB. Home, BLAST, Genome Browser, Transcription Factor and Download interfaces composed of the organizational structure of CeleryDB. Users can search the celery genomic data by using two user-friendly query tools: basic local alignment search tool and Genome Browser. In the future, CeleryDB will be constantly updated to satisfy the needs of celery researchers worldwide. Database URL: http://apiaceae.njau.edu.cn/celerydb [ABSTRACT FROM AUTHOR]

Celery is a vegetable crop with rich nutrition and economic value. It is easy to be affected by abiotic stress in its cultivation. Ascorbate (AsA) is considered as an important nutrient component in vegetable crops and an antioxidant for plants against abiotic stress. Dehydroascorbate reductase (DHAR) is a critical enzyme involved in AsA recycling. The study on the characteristics and functions of DHAR in celery were limited to date. Here, we identified a gene, AgDHAR2 , encoding dehydroascorbate reductase from celery. AgDHAR2 was a chloroplast-localized protein and belonged to the member of glutathione S -transferases (GSTs) with conserved GST_N_3 and GST_C_2 domains. Transcript level of AgDHAR2 and the AsA accumulation in celery cvs. 'Jinnan Shiqin' and 'Huangtaiji' were induced under diverse stress conditions. Transgenic Arabidopsis thaliana and celery plants transformed with AgDHAR2 were generated to further investigate its role in AsA accumulation and drought stress response. Overexpression of AgDHAR2 in A. thaliana and celery led to elevated AsA contents and up-regulated AsA:DHA ratio. When subjected to drought stress, the progeny of transgenic A. thaliana plants hosting AgDHAR2 gene exhibited improved antioxidant-related genes expression, SOD and POD activities, proline accumulation and plant survival rates compared with wild-type plants, thereby showing higher drought tolerance. Taken together, the results of this study demonstrated that AgDHAR2 might contribute to enhanced drought tolerance through increasing AsA concentrations and maintaining redox state in celery. • AgDHAR2, belongs to the member of glutathione S-transferases (GSTs), was a chloroplast-located protein. • Overexpressing AgDHAR2 in celery and A. thaliana exhibited increased ascorbate accumulation and improved redox state. • AgDHAR2 -overexpression contributed to enhanced drought resistance in A. thaliana through modulating ascorbate metabolism. [ABSTRACT FROM AUTHOR]

• Several transgenic A. thaliana and celery lines harboring AgZDS gene were obtained. • The roles of AgZDS gene in carotenoids biosyntheisis were verified. • Overexpression of AgZDS increased the accumulation of lutein and β-carotene. • Antioxidant ability and photosynthetic ability of transgenic plants were improved. ζ-Carotene desaturase (ZDS) is one of the key enzymes regulating carotenoids biosynthesis and accumulation. Celery transgenic efficiency is low and it is difficult to obtain transgenic plants. The study on ZDS was limited in celery. Here, the AgZDS gene was cloned from celery and overexpressed in Arabidopsis thaliana and celery to verify its function. The AgZDS has typical characteristic of ZDS protein and is highly conserved in higher plants. Phylogenetic analysis showed that AgZDS has the closest evolutionary relationship with ZDSs from Solanum lycopersicum , Capsicum annuum and Tagetes erecta. Overexpression of AgZDS gene in A. thaliana and celery resulted in increased accumulations of lutein and β-carotene and up-regulated the expression levels of the genes involved in carotenoids biosynthesis. The contents of lutein and β-carotene in two lines, AtL1 and AgL5, were the highest in transgenic A. thaliana and celery, respectively. The relative expression levels of 5 genes (AtPDS , AtZISO , AtZEP , AtNCED3 , and AtCCD4) were up-regulated compared to the wild type plants. The relative expression levels of most genes in carotenoids biosynthesis pathway, such as AgPDS , AgCRTISO1 , and AgZISO , were up-regulated in transgenic celery plants. The antioxidant capacity of A. thaliana and photosynthetic capacity of celery were also enhanced. This research is the first report on the function of structure gene related to carotenoid biosynthesis in transgenic celery plants. The findings in this study demonstrated the roles of AgZDS in regulating carotenoids metabolism of celery, which laid a potential foundation for quality improvement of celery. [ABSTRACT FROM AUTHOR]

The NAC transcription factor participates in various biotic and abiotic stress responses and plays a critical role in plant development. Lignin is a water-insoluble dietary fiber, but it is second only to cellulose in abundance. Celery is the main source of dietary fiber, but its quality and production are limited by various abiotic stresses. Here, AgNAC1 containing the NAM domain was identified from celery. AgNAC1 was found to be a nuclear protein. Transgenic Arabidopsis thaliana plants hosting AgNAC1 have longer root lengths and stomatal axis lengths than the wide type (WT). The evidence from lignin determination and expression levels of lignin-related genes indicated that AgNAC1 plays a vital role in lignin biosynthesis. Furthermore, the results of the physiological characterization and the drought and salt treatments indicate that AgNAC1 -overexpressing plants are significantly resistive to salt stress. Under drought and salt treatments, the AgNAC1 transgenic Arabidopsis thaliana plants presented increased superoxide dismutase (SOD) and peroxidase (POD) activities and decreased malondialdehyde (MDA) content and size of stomatal apertures relatively to the WT plants. The AgNAC1 served as a positive regulator in inducing the expression of stress-responsive genes. Overall, the overexpressing AgNAC1 enhanced the plants' resistance to salt stress and played a regulatory role in lignin accumulation. • AgNAC1 was a protein located in the nucleus. • Overexpression of AgNAC1 enhanced the drought resistance and salt tolerance. • Overexpression of AgNAC1 promoted lignin accumulation and lignin-related genes expression under salt stress. [ABSTRACT FROM AUTHOR]

• A total of 111 putative NAC TFs were found and identified based on celery transcriptome and genome database. • The AgNAC TFs were classified into 18 subfamilies and their physicochemical properties were preliminary analyzed. • Expression profiles of selected AgNAC genes in response to abiotic stress were detected. In plants, NAC (NAM, ATAF, CUC) is a class of transcription factors (TFs) involved in growth regulation and is associated with abiotic stress, morphogenesis, and metabolism. Celery (Apium graveolens L.) is an important leafy vegetable and its yield and quality are considerably influenced by environmental factors. Currently, the characterization of NAC genes in celery is still limited. In this study, a total of 111 putative NAC TFs were determined based on the celery transcriptome and genome database. They were divided into 18 subfamilies on the basis of their NAC domain. NAC TFs in celery account for a moderate number compared with other species, similar to that in carrot. Real-time quantitative PCR (RT-qPCR) showed that some AgNAC genes were differentially expressed under adverse conditions (heat, cold, drought, and salt). AgNAC63 (ortholog of ANAC072 / RD26) was highly induced by heat, cold, and salt conditions. The expression levels of AgNAC47 in leaf blades were 105.25- and 123.14-fold those of petioles and roots, respectively. AgNAC63 and AgNAC47 showed significant tissue specificity, high expression in leaves, and varying degrees of response under the four treatments. This study provides a basis for the improved investigation of the structure and function of AgNAC TFs and celery stress resistance. [ABSTRACT FROM AUTHOR]