Most days at school, I eat a snack that consists of pineapples — typical, yellow pineapples. However, it has come upon me that my favorite fruit can also be pink?! With the addition of a singular gene, genetically-modified (GMO) pineapples have their yellow inner color turn into bright pink.
In order to add the gene that causes a color change, scientists use a bacterium called Agrobacterium tumefaciens. They use this bacterium since it treats host cells like a virus does and transfers its DNA to the host cell. Thus, by adding Agrobacterium tumefaciens bacteria cells holding the color-changing gene to pineapples, the new gene’s DNA is able to transfer to the genome of a pineapple. I found this DNA transfer process interesting since it illustrates how prokaryotes can work differently:
In the Endosymbiotic Theory that I learned in AP Bio class, it is said that mitochondria and chloroplasts came into eukaryotic cells by being engulfed by them long ago as prokaryotic cells. All prokaryotes have their own DNA, but, different from Agrobacterium tumefaciens, these prokaryotes must have not been able to transfer their DNA to the host cell because the Endosymbiotic Theory is used to explain why mitochondria and chloroplasts have their own DNA separate from the cell, among other features.
Once in the pineapple’s genome, the DNA transcribes RNA, also as I learned in AP Bio class. However, rather than telling a ribosome what protein(s) to make, the RNA here purposefully interferes with the mRNA that pineapples naturally have that tells ribsomes to create an enzyme called lycopene beta-cyclase. This is in order to stop the prodcution of lycopene beta-cyclase, the enzyme which breaks down pineapple’s naturally-occuring pigment of lycopene into beta-carotene and makes pineapples yellow.
With the lycopene beta-cyclase enzyme no longer being synthesized, these GMO pineapples now have a surplus of lycopene; pineapples’ naturally-occuring lycopene is no longer being broken down. Lycopene is the compound that gives many red and pink fruits and vegetables, such as watermelons and grapefruits, their color. Hence, why pineapples high in lycopene concentration shine pink on the inside.
Lastly, if you ever buy one of these pretty pineapples, it came from the company Del Monte in Costa Rica, who patented the GMO pineapples and is therefore the only company allowed to grow them. Fortunately for Del Monte and rightfully so in my opinion, in Costa Rica these pineapples are higher in demand than supply.
Do you want to see more pink pineapples in the world?