Biosynthesis, regulation and functions of tocochromanols in plants

Mène-Saffrané, Laurent; DellaPenna, Dean

doi:10.1016/j.plaphy.2009.11.004

Cited by 205 publications

(137 citation statements)

References 69 publications

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“…Total tocochromanol levels were nearly fivefold higher in Nt-SyHPT plants than in wild-type plants (Fig. 4A), confirming previous data suggesting that HPT has a limiting role in tocopherol biosynthesis (5,10). Most of the additional tocochromanol accumulating in the Nt-SyHPT lines was α-tocopherol, although some β-/γ-tocopherol (not normally accumulating in the wild type) was detectable also.…”

Section: Expression Of Three Enzymes Of Thesupporting

confidence: 88%

“…Our results confirm previous data on the limiting role of HPT in the pathway, characterize the limitations in tocopherol biosynthesis in transplastomic leaves and fruits, and reveal a synthetic operon design that facilitates efficient multigene engineering in plastids. (9,10). Expression of foreign genes from the plastid genome has the advantages that (i) there is no interference from epigenetic processes, and (ii) transgene insertion occurs by homologous recombination into a preselected region of the plastid genome, typically an intergenic spacer region (11)(12)(13).…”

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confidence: 99%

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Efficient metabolic pathway engineering in transgenic tobacco and tomato plastids with synthetic multigene operons

Rijzaani

Karcher

et al. 2013

Proc. Natl. Acad. Sci. U.S.A.

176

137

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The engineering of complex metabolic pathways requires the concerted expression of multiple genes. In plastids (chloroplasts) of plant cells, genes are organized in operons that are coexpressed as polycistronic transcripts and then often are processed further into monocistronic mRNAs. Here we have used the tocochromanol pathway (providing tocopherols and tocotrienols, collectively also referred to as "vitamin E") as an example to establish principles of successful multigene engineering by stable transformation of the chloroplast genome, a technology not afflicted with epigenetic variation and/or instability of transgene expression. Testing a series of single-gene constructs (encoding homogentisate phytyltransferase, tocopherol cyclase, and γ-tocopherol methyltransferase) and rationally designed synthetic operons in tobacco and tomato plants, we (i) confirmed previous results suggesting homogentisate phytyltransferase as the limiting enzymatic step in the pathway, (ii) comparatively characterized the bottlenecks in tocopherol biosynthesis in transplastomic leaves and tomato fruits, and (iii) achieved an up to tenfold increase in total tocochromanol accumulation. In addition, our results uncovered an unexpected light-dependent regulatory link between tocochromanol metabolism and the pathways of photosynthetic pigment biosynthesis. The synthetic operon design developed here will facilitate future synthetic biology applications in plastids, especially the design of artificial operons that introduce novel biochemical pathways into plants.

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Section: Expression Of Three Enzymes Of Thesupporting

confidence: 88%

mentioning

confidence: 99%

Efficient metabolic pathway engineering in transgenic tobacco and tomato plastids with synthetic multigene operons

Rijzaani

Karcher

et al. 2013

Proc. Natl. Acad. Sci. U.S.A.

176

137

View full text Add to dashboard Cite

show abstract

“…The tocochromanols are effective in preventing the propagation of peroxidation. Of these, α-tocopherol and γ-tocopherol (1) are the most common in plants (5,6). Tocochromanols consist of a hydrophobic isoprenoid tail that is anchored into membrane bilayers, whereas a more hydrophilic hydroxychroman ring sits nearer the surface.…”

Section: Tocochromanols Protect Against Lipid Peroxidationmentioning

confidence: 99%

“…However, a strong phenotype is only revealed under under extreme conditions or in combination with mutations in other photoprotective components (6,7). The emergence of PC-8 as a key player in protecting seed lipids and its effectiveness as a singlet oxygen scavenger suggest that the role of tocochromanols in photoprotection of photosynthesis needs further investigation using the vte1 vte2 double mutant.…”

Section: Tocochromanols and Photosynthesismentioning

confidence: 99%

Tocochromanols: Rancid lipids, seed longevity, and beyond

Smirnoff

2010

Proc. Natl. Acad. Sci. U.S.A.

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“…Furthermore,, belonging to a non-glycerol substance, occurs with tocopherols. The compound belongs to the tocopherol-like group, which demonstrate antioxidant properties (Mène-Saff rané and DellaPenna, 2010). Rapeseed oil is a very valuable source of natural bioactive components which contribute to the quenching of free radicals during metabolic processes.…”

Section: Introductionmentioning

confidence: 99%

Study of variation of tocochromanol and phytosterol contents in black and yellow seeds of Brassica napus L. doubled haploid populations

Cegielska-Taras

Nogala‐Kałucka

Szała

et al. 2016

Acta Sci Pol Technol Aliment

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Background. In the study, an analysis of tocopherols, plastochomanol-8 and phytosterols was conducted using DH lines obtained from F1 hybrids of reciprocal crosses between yellow-and black-seeded lines. Material and methods. The biological material for the study consisted of two DH populations of winter oilseed rape obtained from F1 hybrids of reciprocal crosses between two DH lines: yellow-and black-seeded. Seed color was determined using a ColorFlex spectrophotometer. Fat content was determined via pulsed NMR. The levels of tocopherols, and plastochromanol-8 are analyzed using HPLC. Phytosterol contents and composition were determined by the GC method. Results. The fat content of the black-seeded parental line was 49% and this was higher than that of the yellow-seeded parental line (44%). The fat content of DH line populations ranged from 44 to 51%. Total tocopherol content ranged from 460 to 602 mg/kg and the α-T/γ-T ratio was from 0.66 to 1.09. In parental lines H 2 -26 and Z-114 the total tocopherol content was 534 and 525 mg/kg, but the α-T/γ-T ratios were 0.81 and 1.21, respectively. The yellow-seeded parental line (Z-114) was characterized by a higher PC-8 content (81 mg/kg) than the H 2 -26 black-seeded parental line (58 mg/kg). The largest part of the total phytosterol content in seeds of both populations was β-sitosterol from 976 to 2148 mg/kg, followed by campasterol, from 636 to 1364 mg/kg, and brassicasterol from 375 to 678 mg/kg. The total tocopherol content ranged from 462 to 595 mg/kg (population HxZ) and from 460 to 602 mg/kg (population ZxH). Signifi cantly positive correlations were observed between the seed color with α-T (r = 0.38, p < 0.01), γ-T (r = -0,34, p < 0.01) and PC-8 content (r = 0.29, p < 0.01). Correlations between the seed color with total tocopherol and total phytosterol content were not noted. Conclusion. Considering the range of genetic variation among doubled haploids of two populations, selected DH lines may be good parents for further breeding programs focused on increasing the amount and improving the quality of oilseed rapeseed oil. However, further studies will also be made to determine the infl uence of the environment on bioactive compounds in rapeseed oil. Cross direction of parental DH lines: yellow-and black-seeded has some infl uence, albeit not statistically signifi cant, on the diversity of doubled haploid in their populations with regard to average fat, tocochromanol and phytosterol content.

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Biosynthesis, regulation and functions of tocochromanols in plants

Cited by 205 publications

References 69 publications

Efficient metabolic pathway engineering in transgenic tobacco and tomato plastids with synthetic multigene operons

Efficient metabolic pathway engineering in transgenic tobacco and tomato plastids with synthetic multigene operons

Tocochromanols: Rancid lipids, seed longevity, and beyond

Study of variation of tocochromanol and phytosterol contents in black and yellow seeds of Brassica napus L. doubled haploid populations

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