Development of Nongreen Plastids

Thomson, W. W.; Whatley, Jean M.

doi:10.1146/annurev.pp.31.060180.002111

Cited by 196 publications

(103 citation statements)

References 45 publications

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“…Consistently, the low level of Fd-GOGAT (15% of wild-type activity) supplies Glu for the normal growth of the transgenic antisense Fd-GOGAT tobacco lines in which NADH-GOGAT is not detected in leaves and roots (FerrarioMéry et al, 2000;Feraud et al, 2005). As the CC-SE complexes contain a heterogeneous mixture of photosynthetic chloroplasts and nonphotosynthetic plastids at different sites of the same tissue (Thomson and Whatley, 1980;DeWitt and Sussman, 1995), Fd-linked Glu formation in the vascular tissue requires electron donor systems other than chloroplastic PSI. NADPH serves as the primary reductant for Glu formation via the reversed reaction of photosystem-dependent Fd:NADP 1 oxidoreductase (EC 1.18.1.2; Fig.…”

Section: Discussionmentioning

confidence: 90%

Glutamine Synthetase-Glutamate Synthase Pathway and Glutamate Dehydrogenase Play Distinct Roles in the Sink-Source Nitrogen Cycle in Tobacco

et al. 2006

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Glutamate (Glu) metabolism and amino acid translocation were investigated in the young and old leaves of tobacco (Nicotiana tabacum L. cv Xanthi) using [15N]ammonium and [2-15N]Glu tracers. Regardless of leaf age, [15N]ammonium assimilation occurred via glutamine synthetase (GS; EC 6.1.1.3) and Glu synthase (ferredoxin [Fd]-GOGAT; EC 1.4.7.1; NADH-GOGAT; EC 1.4.1.14), both in the light and darkness, and it did not depend on Glu dehydrogenase (GDH; EC 1.4.1.2). The [15N]ammonium and ammonium accumulation patterns support the role of GDH in the deamination of [2-15N]Glu to provide 2-oxoglutarate and [15N]ammonium. In the dark, excess [15N]ammonium was incorporated into asparagine that served as an additional detoxification molecule. The constant Glu levels in the phloem sap suggested that Glu was continuously synthesized and supplied into the phloem regardless of leaf age. Further study using transgenic tobacco lines, harboring the promoter of the GLU1 gene (encoding Arabidopsis [Arabidopsis thaliana] Fd-GOGAT) fused to a GUS reporter gene, revealed that the expression of Fd-GOGAT remained higher in young leaves compared to old leaves, and higher in the veins compared to the mesophyll. Confocal laser-scanning microscopy localized the Fd-GOGAT protein to the phloem companion cells-sieve element complex in the leaf veins. The results are consistent with a role of Fd-GOGAT in supplying Glu for the synthesis and transport of amino acids. Taken together, the data provide evidence that the GS-GOGAT pathway and GDH play distinct roles in the source-sink nitrogen cycle of tobacco leaves.

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Section: Discussionmentioning

confidence: 90%

Glutamine Synthetase-Glutamate Synthase Pathway and Glutamate Dehydrogenase Play Distinct Roles in the Sink-Source Nitrogen Cycle in Tobacco

et al. 2006

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“…Interestingly, several reviews on plastids do not mention the idea that plastids can have a lytic function (reviewed in ref. [21][22][23]. This might indicate that the published data have been deemed less than convincing.…”

Section: Cell Morphology and Cell Deathmentioning

confidence: 99%

Do plastids inDendrobiumcv. Lucky Duan petals function similar to autophagosomes and autolysosomes?

Doorn¹,

Kirasak²,

Sonong³

et al. 2011

Autophagy

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“…When angiosperm seedlings are germinated in the dark, their cotyledons contain another plastid type, the etioplast (Kirk and Tilney- Basset, 1967Basset, , 1978; Thomson and Whatley, 1980). Within this organelle, the prolamellar body is a highly ordered, paracrystalline structure, which is composed of lipids and proteins (Ryberg and Sundqvist, 1991).…”

Section: Morphological Cellular and Molecular Events During The Ligmentioning

confidence: 99%

The Regulation of Enzymes Involved in Chlorophyll Biosynthesis

Reinbothe

1996

European Journal of Biochemistry

126

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All living organisms contain tetrapyrroles. In plants, chlorophyll (chlorophyll a plus chlorophyll b) is the most abundant and probably most important tetrapyrrole. It is involved in light absorption and energy transduction during photosynthesis. Chlorophyll is synthesized from the intact carbon skeleton of glutamate via the C, pathway. This pathway takes place in the chloroplast. It is the aim of this review to summarize the current knowledge on the biochemistry and molecular biology of the C,-pathway enzymes, their regulated expression in response to light, and the impact of chlorophyll biosynthesis on chloroplast development. Particular emphasis will be placed on the key regulatory steps of chlorophyll biosynthesis in higher plants, such as 5-aminolevulinic acid formation, the production of Mg*+-protoporphyrin IX, and light-dependent protochlorophyllide reduction.

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Development of Nongreen Plastids

Cited by 196 publications

References 45 publications

Glutamine Synthetase-Glutamate Synthase Pathway and Glutamate Dehydrogenase Play Distinct Roles in the Sink-Source Nitrogen Cycle in Tobacco

Glutamine Synthetase-Glutamate Synthase Pathway and Glutamate Dehydrogenase Play Distinct Roles in the Sink-Source Nitrogen Cycle in Tobacco

Do plastids inDendrobiumcv. Lucky Duan petals function similar to autophagosomes and autolysosomes?

The Regulation of Enzymes Involved in Chlorophyll Biosynthesis

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