Developmental stage- and concentration-specific sodium nitroprusside application results in nitrate reductase regulation and the modification of nitrate metabolism in leaves of<i><i>Medicago truncatula</i></i>plants

Antoniou, Chrystalla; Filippou, Panagiota; Mylona, Photini V.; Fasoula, Dionysia A.; Ioannides, Ioannis M.; Polidoros, Alexios N.; Fotopoulos, Vasileios

doi:10.4161/psb.25479

Cited by 36 publications

(21 citation statements)

References 69 publications

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“…It is also possible that higher concentrations of all tocochromanols result in a negative feedback regulatory mechanism, thus inhibiting these HPPD, VTE2, and HGGT biosynthetic enzymes. The same negative feedback regulation pattern has been also observed in other biological systems such as that in M. truncatula plants where nitric oxide (NO) accumulation results in a decline in nitrate reductase (NR) activity, the major contributor of NO biosynthesis (Antoniou et al, 2013 ).…”

Section: Discussionsupporting

confidence: 55%

Temporal analysis reveals a key role for VTE5 in vitamin E biosynthesis in olive fruit during on-tree development

et al. 2015

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The aim of this work was to generate a high resolution temporal mapping of the biosynthetic pathway of vitamin E in olive fruit (Olea europaea cv. “Koroneiki”) during 17 successive on-tree developmental stages. Fruit material was collected from the middle of June until the end of January, corresponding to 6–38 weeks after flowering (WAF). Results revealed a variable gene regulation pattern among 6–38 WAF studied and more pronounced levels of differential regulation of gene expression for the first and intermediate genes in the biosynthetic pathway (VTE5, geranylgeranyl reductase, HPPD, VTE2, HGGT and VTE3) compared with the downstream components of the pathway (VTE1 and VTE4). Notably, expression of HGGT and VTE2 genes were significantly suppressed throughout the developmental stages examined. Metabolite analysis indicated that the first and intermediate stages of development (6–22 WAF) have higher concentrations of tocochromanols compared with the last on-tree stages (starting from 24 WAF onwards). The concentration of α-tocopherol (16.15 ± 0.60−32.45 ± 0.54 mg/100 g F.W.) were substantially greater (up to 100-fold) than those of β-, γ-, and δ-tocopherols (0.13 ± 0.01−0.25 ± 0.03 mg/100 g F.W., 0.13 ± 0.01−0.33 ± 0.04 mg/100 g F.W., 0.14 ± 0.01−0.28 ± 0.01 mg/100 g F.W., respectively). In regard with tocotrienol content, only γ-tocotrienol was detected. Overall, olive fruits (cv. “Koroneiki”) exhibited higher concentrations of vitamin E until 22 WAF as compared with later WAF, concomitant with the expression profile of phytol kinase (VTE5), which could be used as a marker gene due to its importance in the biosynthesis of vitamin E. To the best of our knowledge, this is the first study that explores the complete biosynthetic pathway of vitamin E in a fruit tree crop of great horticultural importance such as olive, linking molecular gene expression analysis with tocochromanol content.

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Section: Discussionsupporting

confidence: 55%

Temporal analysis reveals a key role for VTE5 in vitamin E biosynthesis in olive fruit during on-tree development

et al. 2015

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“…Similarly, temperature was lowest during the 1 st year (average air temperature 16.28°C for 22–30 WAF), which slightly increased during the 2 nd year (average air temperature 16.78°C for 22–30 WAF) but showed about 2°C temperature increase in the ripening phase reaching highest levels during the 3 rd year (average air temperature 18.23°C for 22–30 WAF) ( Table 1 ; Supplementary Figure S2). It is possible that, in a defense attempt against water deficit conditions and increased air temperature, transcription of genes involved in vitamin E biosynthesis (excluding VTE5 ) is up-regulated in olive fruit, probably leading to the blocking/deactivating of the pathway through a negative feedback regulatory mechanism (Antoniou et al, 2013) which results in decreasing tocochromanols, VTE5 content and antioxidant capacity as the olive fruit develops to maturity.…”

Section: Discussionmentioning

confidence: 99%

Regulation of On-Tree Vitamin E Biosynthesis in Olive Fruit during Successive Growing Years: The Impact of Fruit Development and Environmental Cues

et al. 2016

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The term vitamin E refers to a group of eight lipophilic compounds known as tocochromanols. The tocochromanols are divided into two groups, that is, tocopherols and tocotrienols, with four forms each, namely α-, β-, γ-, and δ-. In order to explore the temporal biosynthesis of tocochromanols in olive (Olea europaea cv. ‘Koroneiki’) fruit during on-tree development and ripening over successive growing years, a combined array of analytical, molecular, bioinformatic, immunoblotting, and antioxidant techniques were employed. Fruits were harvested at eight successive developmental stages [10–30 weeks after flowering (WAF)], over three consecutive years. Intriguingly, climatic conditions affected relative transcription levels of vitamin E biosynthetic enzymes; a general suppression to induction pattern (excluding VTE5) was monitored moving from the 1st to the 3rd growing year, probably correlated to decreasing rainfall levels and higher temperature, particularly at the fruit ripening stage. A gradual diminution of VTE5 protein content was detected during the fruit development of each year, with a marked decrease occurring after 16 WAF. Alpha-tocopherol was the most abundant metabolite with an average percentage of 96.82 ± 0.23%, 91.13 ± 0.95%, and 88.53 ± 0.96% (during the 1st, 2nd, and 3rd year, respectively) of total vitamin E content in 10–30 WAF. The concentrations of α-tocopherol revealed a generally declining pattern, both during the on-tree ripening of the olive fruit and across the 3 years, accompanied by a parallel decline of the total antioxidant capacity of the drupe. Contrarily, all other tocochromanols demonstrated an inverse pattern with lowest levels being recorded during the 1st year. It is likely that, in a defense attempt against water deficit conditions and increased air temperature, transcription of genes involved in vitamin E biosynthesis (excluding VTE5) is up-regulated in olive fruit, probably leading to the blocking/deactivating of the pathway through a negative feedback regulatory mechanism.

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“…Previous reports have suggested NO as a stress-inducing agent (Antoniou et al 2014), whereas others have assigned it as a protective molecule (Tanou et al 2012), functioning as an antioxidant by scavenging ROS (Laspina et al 2005). Moreover, NO can reduce superoxide anion formation and lipid peroxidation (Boveris et al 2000).…”

Section: Introductionmentioning

confidence: 97%

Salicylic acid and nitric oxide increase photosynthesis and antioxidant defense in wheat under UV-B stress

Yan¹,

Liu²,

Sheng³

et al. 2016

Biol. plant.

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The effects of exogenous salicylic acid (SA), sodium nitropusside (SNP, a nitric oxide donor), or their combination on dwarf polish wheat (Triticum polonicum L.) seedlings under UV-B stress were studied. UV-B stress significantly decreased plant height, shoot dry mass, pigment content, net photosynthetic rate, intercellular CO 2 concentration, stomatal conductance, transpiration rate, and variable to maximum chlorophyll fluorescence ratio (F v /F m ) in all plants, but less in the presence of SA, SNP, and their combination. On the other hand, there were considerable increases in malondialdehyde, proline, O 2•-and H 2 O 2 content under UV-B stress. When SA, SNP, and their combination were applied, the content of MDA, proline, H 2 O 2 , and O 2 •-was less increased. Moreover, there were considerable increases in activities of superoxide dismutase, peroxidase, ascorbate peroxidase, and glutathione reductase under UV-B stress and more in the presence of SA, SNP, and their combination. Therefore, it is considered that the combination of SA, SNP, and especially their combination can alleviate UV-B stress in dwarf polish wheat.

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Developmental stage- and concentration-specific sodium nitroprusside application results in nitrate reductase regulation and the modification of nitrate metabolism in leaves ofMedicago truncatulaplants

Cited by 36 publications

References 69 publications

Temporal analysis reveals a key role for VTE5 in vitamin E biosynthesis in olive fruit during on-tree development

Temporal analysis reveals a key role for VTE5 in vitamin E biosynthesis in olive fruit during on-tree development

Regulation of On-Tree Vitamin E Biosynthesis in Olive Fruit during Successive Growing Years: The Impact of Fruit Development and Environmental Cues

Salicylic acid and nitric oxide increase photosynthesis and antioxidant defense in wheat under UV-B stress

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