Every other week Mallory Locklear, a graduate student at Stony Brook University’s Department of Neurobiology and Behavior, will take a look at Stony Brook-related research and science news.

(PHOTO CREDIT : MCTCAMPUS)
Agrobacterium injects its DNA into other plant species, a process scientists use to add other nutrients to food. (PHOTO CREDIT : MCTCAMPUS)

Golden rice is a genetically modified crop. The difference between it and its standard rice counterpart is that small changes have been introduced that allow it to produce beta-carotene, the precursor to Vitamin A.

Golden rice was developed in order to fight Vitamin A deficiency, a severe problem across the developing world. It has been estimated that in developing countries, as many as 40 percent of children under the age of five are affected by Vitamin A deficiency, which can lead to blindness, immune system problems and death.

Vitamin A deficiency occurs in regions that lack available crops naturally containing beta-carotene, like carrots and sweet potatoes, and have high poverty levels that prevent the purchase of such crops.

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One serving of golden rice, a comparatively inexpensive food, can provide up to 60 percent of a child’s recommended intake of Vitamin A.

However, due to campaigns against the use of genetically modified crops, including those led by the environmental organization Greenpeace, many people and countries have grown resistant to the idea of spreading, growing and consuming genetically modified crops like golden rice.

But what is the science behind genetically modified plants?

On this topic, Vitaly Citovsky, a professor in Stony Brook’s department of Biochemistry and Cell Biology, says, “If people understood it, how it works, they would not be afraid.”

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Thus, Citovsky’s research team studies the process by which many genetically modified crops work, from golden rice to insect-resistant plants.

Nearly all of these crops are produced the same way–with a type of bacterium called Agrobacterium.

Agrobacterium is naturally occurring and very common. As Citovsky explained, if you put your hand in a garden, it will be covered with Agrobacterium.

Agrobacterium has not been found to be harmful to animals and is generally harmless to plants.  However, when Agrobacterium needs a food source, it has an interesting way of getting it.

The bacteria attach to a tree and put a little bit of their own DNA into the tree’s cells. This bit of DNA tells the cells to do two things. The first is that it tells the cells to replicate, creating an abundance of cells, or a tumor. The second is that it tells the tumor of cells to produce a variety of chemicals that the plant itself treats as waste but provides the bacteria with essential nutrients like nitrogen.

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Though it can sometimes be harmful to the tree, the relationship can often coexist without damaging effects.

According to Citovsky, the trickiest part of this process is getting the DNA from the bacteria and into the tree’s cells. Unlike our cells, plant cells have a rather strong cell wall that makes moving in and out of the cell difficult. Agrobacterium has developed ways around this, making the bacteria very useful tools for plant biologists.

Because Agrobacterium has already found a way to get into plant cells, scientists can take the DNA it inserts into trees and change the DNA’s message to suit their own purposes.  So, while Agrobacterium is telling the tree to make it food, scientists can use the DNA to tell the plant to make any number of things.

Scientists do this by taking the beginnings and ends of the Agrobacterium DNA, while cutting out everything else in between and replacing it with something new, changing the message the DNA is sending to the plant it gets put into. It is like the scientists kept the capital letter and period that marks the beginning and end of this sentence, but they changed all of the words in between.

Now, rather than having a piece of DNA that tells the plant to make food for the bacteria, the DNA can tell the plant to make other things, such as beta-carotene in the example of golden rice.

This method can and has been used in the development of a number of genetically modified crops.

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Citovsky wants to better understand how Agrobacterium works, how it tells the cell to do what it does, and in what other ways the bacteria can be used.

A better understanding of this bacteria could change attitudes on genetically modified crops and may lead to more advanced genetic tools for researchers to work with in the future.

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