Arabidopsis Plastids: The Little Capsule with a Huge Impact

Looking at plants, one may think that they are quiet, and they don't seem to do much. However, the plant is actually constantly toiling away, day and night, producing sugars, breaking large molecules down into energy, preparing for winter, growing, and healing itself. Much of the work done by the plant is carried out by small cellular components called plastids. These organells are often found in a specialized state, such as the starch storing and gravity detecting amyloplasts primarily found in root tissue. It is these plastids that allow plant tissues to specialize and perform functions critical to plant survival. In the example of root amyloplasts, these are the key components that allow the root tissue to store energy for the plant, in the form of starch, which forms tubors and fleshy roots in some plants.

My research is concerned with studying the complex reactions that take place in the plastids. Specifically, I work with chloroplasts, which are the green plastids responsible for carrying out photosynthesis. To capture sunlight and use its energy to produce sugars, the chloroplasts are most commonly found in plant leaves. If a chloroplast is not exposed to sunlight, it is called an etioplast, the white, semi-specialized precursor of the chloroplast. To better understand how photosynthetic proteins and enzymes are regulated in the time before the chloroplast becomes specialized, I am interested in studying the proteins of the etioplast. To find these plastids, I plan to collect plant root tissue and perform tests that indicate what the proteins do under certain conditions of the plant. I will also work with plants that have a mutated version of the proteins of interest, to see how removing the function of the protein will affect the plant.

So far, my laboratory work has been concerned with establishing a few basic things before I am able to really study the enzyme/protein connections in root plastids. I must first be able to grow large amounts of root tissue from my model plant Arabidopsis thaliana. I've tried hydroponics, glass bead culture, and vermiculite, but hydroponics seems to be the most successful. Next, I need to figure out if I can find the proteins in which I am interested just by processing the whole root tissue, or if I must isolate the plastids from the root tissue to be able to find these proteins. Once I find the plastid proteins, I will then work to further isolate the proteins that are specifically modified and see how these differ between the wild type and the mutated plants.