Target-directed discovery and production of pharmaceuticals in transgenic mutant plant cells

J Biotechnol. 2016 Nov 20:238:9-14. doi: 10.1016/j.jbiotec.2016.09.007. Epub 2016 Sep 13.


Plants are a source of complex bioactive compounds, with value as pharmaceuticals, or leads for synthetic modification. Many of these secondary metabolites have evolved as defenses against competing organisms and their pharmaceutical value is "accidental", resulting from homology between target proteins in these competitors, and human molecular therapeutic targets. Here we show that it is possible to use mutation and selection of plant cells to re-direct their "evolution" toward metabolites that interact with the therapeutic target proteins themselves. This is achieved by expressing the human target protein in plant cells, and selecting mutants for survival based on the interaction of their metabolome with this target. This report describes the successful evolution of hairy root cultures of a Lobelia species toward increased biosynthesis of metabolites that inhibit the human dopamine transporter protein. Many of the resulting selected mutants are overproducing the active metabolite found in the wild-type plant, but others overproduce active metabolites that are not readily detectable in non-mutants. This technology can access the whole genomic capability of a plant species to biosynthesize metabolites with a specific target. It has potential value as a novel platform for plant drug discovery and production, or as a means of optimizing the therapeutic value of medicinal plant extracts.

Keywords: 1,2,3,6-tetrahydropyridine (MPTP); 1,2,3,6-tetrahydropyridine (MPTP: Pubmed CID: 1388); 1-methy-4-phenylpyridinium (MPP+: Pubmed CID: 39484); Activation tagging mutagenesis (ATM); Hairy root cultures; Human dopamine transporter protein (hDAT); Lobelia cardinalis; Lobinaline (1-Methyl-5,7-diphenyl-6-(3,4,5,6-tetrahydro-2-pyridinyl)decahydroquinoline (Pubmed CID: 419029); [(3)H]GBR12935 (Pubmed CID: 3455).

MeSH terms

  • Dopamine Plasma Membrane Transport Proteins / genetics
  • Dopamine Plasma Membrane Transport Proteins / metabolism
  • Humans
  • Lobelia* / cytology
  • Lobelia* / genetics
  • Lobelia* / metabolism
  • Plant Cells / metabolism*
  • Plant Roots
  • Plants, Genetically Modified* / cytology
  • Plants, Genetically Modified* / genetics
  • Plants, Genetically Modified* / metabolism
  • Protein Engineering / methods*
  • Recombinant Proteins* / genetics
  • Recombinant Proteins* / metabolism
  • Tissue Culture Techniques


  • Dopamine Plasma Membrane Transport Proteins
  • Recombinant Proteins