Scientists from the Max Planck Institute of Molecular Plant Physiology have recently uncovered a new method for genetically modifying plants by manipulating the genes found in chloroplast.

As you may already know, the chloroplast aids in plant survival, as this organelle takes on the responsibility helping the plant to carry out photosynthesis; but more importantly, the chloroplast forms proteins that could undergo genetic modification to ultimately make plants capable of drug delivery or possibly even improve the safety of genetically modified plants.

The study, published in the Proceeding of the National Academy of Sciences, documents a unique process of genetic modification that induces RNA molecules to alter their spatial structure and allows for the manipulation of protein production in the chloroplast.  Controlling the formation of certain chloroplast proteins occurs when scientists smuggle a gene coding for “riboswitches” into the DNA of a chloroplast.

Following the insertion of the riboswitch into tobacco plant chloroplasts, the plants were sprayed with a substance found in the tea plant, called Theophylline.  In this case, theophylline acts like a “switch” that will bind to the inserted riboswitch on the messenger RNA of the tobacco plant to enable the chloroplast ribosomes to read the RNA.  In simpler terms, when tobacco plants are sprayed with theophylline, the chloroplasts will form the corresponding protein, but when depriving the plant of theophylline, no protein was produced; thus, the protein switch flips on with theophylline and off without it!

This newfound knowledge of riboswitches will give way for advances in biotechnology.  For instance, each tobacco plant contains approximately 100 chloroplasts; thus, the chloroplast has a much larger protein building arsenal than the DNA of the cell nucleus, so when the chloroplasts were modified, the tobacco plant could produce larger than normal quantities of antibiotic in the leaves.

Discussion Question: What part of the chloroplast functions to carry out photosynthesis in the plant?

News Article: http://www.sciencedaily.com/releases/2010/03/100330092817.htm
Scientific Abstract: http://www.pnas.org/content/107/14/6204.full