What if humanity could travel to farther reaches of outer space, or colonize the hostile environments found there? How might plant life thrive in non-gravity environments? What if we could genetically engineer plants to dramatically increase our crop yield per acre? Outcomes such as these may eventually be found through the work being conducted now in the lab of Dr. Darron Luesse, professor of biological sciences.
NASA has taken an interest in the possible breakthroughs of Luesse’s experiments, conducted through a project led by Ohio University and supported by nearly $400,000 in grant funds. Luesse and Dr. Sarah E. Wyatt of Ohio are exploring questions about how gravity affects the complicated process of environmentally-regulated plant growth and development.
“From a plant’s point of view, gravity is a critical piece of information about where it is in the world—light is usually up, and water and nutrients are usually down—but a plant in space is missing
While animals can alter their environments or move to new ones, plants are immobile, and instead will often change how they grow in a way that best suits available resources. Because one of the most important and informative aspects of an environment is gravity, this force plays a role in nearly every aspect of a plant’s development. On earth, this can be seen in the growth patterns of seedlings. When a seed germinates underground without light, it has only gravity to guide its growth in the direction of likely resources. Adult plants also respond to gravity, as can be seen in the angle that branches emerge from the main shoot. Through a process called gravitropism, plants may change their growth in response to a change in the direction of gravity, for example when wind causes a plant to fall over. Shoots will immediately begin to grow towards the new upward direction, while roots will grow down.
According to Luesse, “From a plant’s point of view, gravity is a critical piece of information about where it is in the world—light is usually up, and water and nutrients are usually down—but a plant in space is missing that sense. They don't do as well in this environment. We want to learn specifically why this happens, so that we can potentially address, through genetic engineering or growth practices, how to grow healthier plants in space.” Not only that, but understanding this process can perhaps provide opportunities for biotechnology to enhance crop species and agricultural output here on earth.
The key to understanding Luesse’s work lies in the genes of the unassuming Arabidopsis thaliana, or thale cress plant. This plant, unheralded outside the scientific community, (“You can’t eat it and you can’t smoke it…” Luesse points out) has been heavily researched, he says, “due to its short life cycle, small size, abundant molecular tools and most importantly, its small, sequenced genome.” Rather than simply observe how plants grow under different gravity conditions, knowledge of the genome’s sequence allows researchers to predict which genes (and the corresponding proteins) are involved in, and how they are contributing to, overall plant development with and without gravity.
By using the sequence of an entirely known genome, like that of Arabidopsis, scientists can identify all of the potential genes and predict the proteins that can potentially be made from those genes. While genes provide the instructions for making proteins, it is the proteins themselves that are active in cells, catalyzing reactions and directing growth and development. By understanding each protein’s function and when it is used, scientists can determine which specific proteins are involved in a cellular process and how they may regulate it. According to Luesse, his project begins by focusing on the question of which proteins are used by the plant to sense gravity, but also hopes to address the question of what each protein does. “Basically,” he said, “we are asking which proteins a plant chooses to produce when it is living in a microgravity environment, and how that decision differs from plants growing in regular gravity conditions. The proteins that are present in one sample, but not the other, or are present in different amounts, represent the interesting topics for future research.”
Finding the reasons why one sample differs from another, what specific proteins do for a plant, or why a plant produces or halts production of a protein under certain gravity conditions, Luesse said, may lead to new agricultural practices or targets for genetically engineering plants that would allow them to grow closer together here on Earth. Perhaps the tiny seeds of Arabidopsis could eventually allow humanity to feed more people. Perhaps we will begin to understand how to best grow plants on other planets. Through the research of Dr. Darron R. Luesse, these things, and others, seem possible.