ArticlePlant physiology2001
Targeting a nuclear anthranilate synthase alpha-subunit gene to the tobacco plastid genome results in enhanced tryptophan biosynthesis. Return of a gene to its pre-endosymbiotic origin.
Article in Plant physiology, 2001. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 19 papers.
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Who cites it
19 citing papers in PubMed, 61 citations in OpenAlex.
- OsASA2 Loss-of-Function Confers Broad-Spectrum Disease Resistance and Triggers Cell Death by Regulating Anthranilate Synthase Activity in Rice.Molecular plant pathology · 2026Article
- Evolution of aromatic amino acid metabolism in plants: a key driving force behind plant chemical diversity in aromatic natural products.Philosophical transactions of the Royal Society of London. Series B, Biological sciences · 2024Review
- Physico-chemical characterization and transcriptome analysis of 5-methyltryptophan resistant lines in rice.PloS one · 2019Article
- Fortifying Horticultural Crops with Essential Amino Acids: A Review.International journal of molecular sciences · 2017Review
- Improving Nutritional Quality of Plant Proteins Through Genetic Engineering.Current genomics · 2016Article
- Production of functional native human interleukin-2 in tobacco chloroplasts.Molecular biotechnology · 2014Article
- Inhibition of p-aminobenzoate and folate syntheses in plants and apicomplexan parasites by natural product rubreserine.The Journal of biological chemistry · 2012Article
- Increased glutamine in leaves of poplar transgenic with pine GS1a caused greater anthranilate synthetase α-subunit (ASA1) transcript and protein abundances: an auxin-related mechanism for enhanced growth in GS transgenics?Journal of experimental botany · 2011Article
- Tobacco plastid transformation using the feedback-insensitive anthranilate synthase [alpha]-subunit of tobacco (ASA2) as a new selectable marker.Journal of experimental botany · 2009Article
- Tissue culture specificity of the tobacco ASA2 promoter driving hpt as a selectable marker for soybean transformation selection.Plant cell reports · 2008Article
- Use of 4-methylindole or 7-methyl-DL-tryptophan in a transformant selection system based on the feedback-insensitive anthranilate synthase alpha-subunit of tobacco (ASA2).Plant cell reports · 2008Article
- Chloroplast vector systems for biotechnology applications.Plant physiology · 2007Review
- Expression of a feedback insensitive anthranilate synthase gene from tobacco increases free tryptophan in soybean plants.Plant cell reports · 2007Article
- Article
- Chorismate derived C6C1 compounds in plants.Planta · 2005Review
- Structure-based in vitro engineering of the anthranilate synthase, a metabolic key enzyme in the plant tryptophan pathway.Plant physiology · 2005Article
- Overexpression of the feedback-insensitive anthranilate synthase gene in tobacco causes tryptophan accumulation.Plant cell reports · 2005Article
- Generation of fertile transplastomic soybean.Plant molecular biology · 2004Article
- Milestones in chloroplast genetic engineering: an environmentally friendly era in biotechnology.Trends in plant science · 2002Review
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Authors and funding
4 authors at 1 institution in 1 country.
Funding
No grant is acknowledged in the PubMed record.
Abstract
Anthranilate synthase (AS), the control enzyme of the tryptophan (Trp) biosynthetic pathway, is encoded by nuclear genes, but is transported into the plastids. A tobacco (Nicotiana tabacum) cDNA (ASA2) encoding a feedback-insensitive tobacco AS alpha-subunit was transformed into two different sites of the tobacco plastid genome through site-specific insertion to obtain transplastomic plants with normal phenotype and fertility. A high and uniform level of ASA2 mRNA was observed in the transplastomic plants but not in the wild type. Although the plants with the transgene insertion at ndhF-trnL only expressed one size of the ASA2 mRNA, the plants with the transgene incorporated into the region between accD and open reading frame (ORF) 184 exhibited two species of mRNA, apparently due to readthrough. The transplastomic plants exhibited a higher level of AS alpha-subunit protein and AS enzyme activity that was less sensitive to Trp-feedback inhibition, leading to greatly increased free Trp levels in leaves and total Trp levels in seeds. Resistance to an AS inhibitor, 5-methyl-Trp, was found during seed germination and in suspension cultures of the transplastomic plants. The resistance to the selection agent spectinomycin and to 5-methyl-Trp was transmitted maternally. These results demonstrate the feasibility of modifying the biosynthetic pathways of important metabolites through transformation of the plastid genome by relocating a native gene from the nucleus to the plastid genome. Very high and uniform levels of gene expression can be observed in different lines, probably due to the identical insertion sites, in contrast to nuclear transformation where random insertions occur.
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