Synthesis of prenylquinones in chloroplasts

Schultz, Gernot; Soll, Jürgen; Fiedler, Erich; Schulze-Siebert, D.

doi:10.1111/j.1399-3054.1985.tb01222.x

Cited by 55 publications

(22 citation statements)

References 47 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Under these conditions, it is frequently difficult to determine the contributions of individual transporters to the overall flux of metabolites. From a metabolic perspective, it is interesting that earlier compartmentation studies have shown that several enzymes of the plastid prenyllipid pathway are partially located in the plastid envelope (for review, see Schultz et al, 1985). It has also been shown that the methylation of MgProto IX takes place in the plastid envelope as well as in the thylakoids (Block et al, 2002).…”

Section: Discussionmentioning

confidence: 99%

ArabidopsisSAMT1 Defines a Plastid Transporter Regulating Plastid Biogenesis and Plant Development

et al. 2006

View full text Add to dashboard Cite

S-Adenosylmethionine (SAM) is formed exclusively in the cytosol but plays a major role in plastids; SAM can either act as a methyl donor for the biogenesis of small molecules such as prenyllipids and macromolecules or as a regulator of the synthesis of aspartate-derived amino acids. Because the biosynthesis of SAM is restricted to the cytosol, plastids require a SAM importer. However, this transporter has not yet been identified. Here, we report the molecular and functional characterization of an Arabidopsis thaliana gene designated SAM TRANSPORTER1 (SAMT1), which encodes a plastid metabolite transporter required for the import of SAM from the cytosol. Recombinant SAMT1 produced in yeast cells, when reconstituted into liposomes, mediated the counter-exchange of SAM with SAM and with S-adenosylhomocysteine, the by-product and inhibitor of transmethylation reactions using SAM. Insertional mutation in SAMT1 and virus-induced gene silencing of SAMT1 in Nicotiana benthamiana caused severe growth retardation in mutant plants. Impaired function of SAMT1 led to decreased accumulation of prenyllipids and mainly affected the chlorophyll pathway. Biochemical analysis suggests that the latter effect represents one prominent example of the multiple events triggered by undermethylation, when there is decreased SAM flux into plastids.

show abstract

Section: Discussionmentioning

confidence: 99%

ArabidopsisSAMT1 Defines a Plastid Transporter Regulating Plastid Biogenesis and Plant Development

et al. 2006

View full text Add to dashboard Cite

show abstract

“…The first true step of tocopherol biosynthesis is the condensation of the precursors homogentisate and phytyl pyrophosphate, the former providing the head group, the latter the hydrophobic tail (Whistance and Threlfall 1970;Schultz et al 1985;Hirschberg 1999;Hofius and Sonnewald 2003).…”

Section: Introductionmentioning

confidence: 99%

Enhancement of vitamin E production in sunflower cell cultures

et al. 2004

View full text Add to dashboard Cite

The most biologically active component of vitamin E, alpha-tocopherol, is synthesized in its most effective stereoisomeric form only by photosynthetic organisms. Using sunflower cell cultures, a suitable in vitro production system of natural alpha-tocopherol was established. The most efficient medium was found to be MS basal medium with naphthaleneacetic acid and 6-benzylaminopurine with the addition of casaminoacids and myo-inositol. Culture feeding experiments using biosynthetic precursors showed that alpha-tocopherol production improved by 30% when homogentisic acid was used. Interestingly, time-course experiments with sunflower suspension cultures showed a possible increase of 78% in alpha-tocopherol production when using cultures of longer subculture intervals. Compared to the starting plant tissue, an overall 100% increase of alpha-tocopherol was reached by these sunflower cell cultures.

show abstract

“…The biosynthetic pathway for vitamin E has been elucidated several years ago [8], but the genes encoding the enzymes of the pathway have been identified only very recently (for a review see [4]). An important step in the early pathway is the formation of homogentisate (HGA) from 4‐hydroxyphenylpyruvate and molecular oxygen, catalyzed by the enzyme 4‐hydroxyphenylpyruvate dioxygenase (HPPD, EC 1.13.11.27).…”

Section: Introductionmentioning

confidence: 99%

Constitutive overexpression of barley 4‐hydroxyphenylpyruvate dioxygenase in tobacco results in elevation of the vitamin E content in seeds but not in leaves¹

et al. 2003

View full text Add to dashboard Cite

With the aim to enhance the plant vitamin E content, the barley gene encoding 4-hydroxyphenylpyruvate dioxygenase was overexpressed in tobacco plants under control of the 35S promoter. Transgenic lines have a higher capacity for homogentisate biosynthesis as evident by a more than 10-fold higher resistance towards the bleaching herbicide sulcotrione. Seeds from transgenic lines have an up to two-fold enhanced level of vitamin E without a change in the ratio of Q Q-tocopherol and Q Q-tocotrienol. While the vitamin E content is not a¡ected in leaves, the level of plastoquinone is enhanced in leaves of transgenic lines during leaf senescence.

show abstract

Synthesis of prenylquinones in chloroplasts

Cited by 55 publications

References 47 publications

ArabidopsisSAMT1 Defines a Plastid Transporter Regulating Plastid Biogenesis and Plant Development

ArabidopsisSAMT1 Defines a Plastid Transporter Regulating Plastid Biogenesis and Plant Development

Enhancement of vitamin E production in sunflower cell cultures

Constitutive overexpression of barley 4‐hydroxyphenylpyruvate dioxygenase in tobacco results in elevation of the vitamin E content in seeds but not in leaves¹

Contact Info

Product

Resources

About

Synthesis of prenylquinones in chloroplasts

Cited by 55 publications

References 47 publications

ArabidopsisSAMT1 Defines a Plastid Transporter Regulating Plastid Biogenesis and Plant Development

ArabidopsisSAMT1 Defines a Plastid Transporter Regulating Plastid Biogenesis and Plant Development

Enhancement of vitamin E production in sunflower cell cultures

Constitutive overexpression of barley 4‐hydroxyphenylpyruvate dioxygenase in tobacco results in elevation of the vitamin E content in seeds but not in leaves1

Contact Info

Product

Resources

About

Constitutive overexpression of barley 4‐hydroxyphenylpyruvate dioxygenase in tobacco results in elevation of the vitamin E content in seeds but not in leaves¹