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Transplastomic plant
From Wikipedia, the free encyclopedia
A transplastomic plant is a genetically modified plant in which genes are inactivated, modified or new foreign genes are inserted into the DNA of plastids like the chloroplast instead of nuclear DNA.
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Currently, the majority of transplastomic plants are a result of chloroplast manipulation due to poor expression in other plastids.[1] However, the technique has been successfully applied to the chromoplasts of tomatoes.[2]
Chloroplasts in plants are thought to have originated from an engulfing event of a photosynthetic bacteria (cyanobacterial ancestor) by a eukaryote.[3] There are many advantages to chloroplast DNA manipulation because of its bacterial origin. For example, the ability to introduce multiple genes (operons) in a single step instead of many steps and the simultaneous expression of many genes with its bacterial gene expression system.[4] Other advantages include the ability to obtain organic products like proteins at a high concentration and the fact that production of these products will not be affected by epigenetic regulation.[5]
The reason for product synthesis at high concentrations is because a single plant cell can potentially carry up to 100 chloroplasts. If all these plastids are transformed, all of them can express the introduced foreign genes.[1] This is may be advantageous compared to transformation of the nucleus, because the nucleus typically contains only one or two copies of the gene.[1]
The advantages provided by chloroplast DNA manipulation has seen growing interest into this field of research and development, particularly in agricultural and pharmaceutical applications.[5] However, there are some limitations in chloroplast DNA manipulation, such as the inability to manipulate cereal crop DNA material and poor expression of foreign DNA in non- green plastids as mentioned before.[5] In addition, the lack of post- translational modification capability like glycosylation in plastids may make some human- related protein expression difficult.[6] Nevertheless, much progress has been made into plant transplastomics, for example, the production of edible vaccines for Tetanus by using a transplastomic tobacco plant.[7]