To-may-to, To-mah-to: Genetic Adaptability Can Help Guard Against Global Climate Change
Chenming Cui, a PhD researcher, is studying how wild tomatoes respond to drought and herbivory stress.
According to the United States Department of Agriculture, the average cost of a pound of tomatoes is $3.16. Tomatoes are consumed both raw and cooked, as sauce, as soup, on sandwiches, in salads, and as a key ingredient in a Bloody Mary. But the tomato is also one of many crops that will be threatened by the increasing effects of climate change. They require precise and involved care, and as weather patterns become more erratic and the planet warms, the delicate balance required for your garden variety tomato will become harder to achieve. However, locked within the genetic code of the plant is a superpower that can change all of that.
The tomato plant comes from along the western coast of South America. Wild plants grow in areas scattered over 30 degrees of latitude, in all sorts of biomes—including deserts, mountains, and rain forests. When Spanish settlers arrived, they took the plant back with them to Europe, and it spread as a decorative plant in gardens across the continent. They didn’t eat it, though; because of its close relation to nightshade, the whole plant was considered poison. Eventually it was brought to North America, where it decorated the gardens of Presidents Thomas Jefferson and George Washington. Slowly, the plant’s fruit gained acceptance as a staple of American and European kitchens.
A small piece of South America rests on a shelf in lab 411 in Latham Hall at Virginia Tech, against the right wall. Ph.D. student and researcher Chenming Cui studies the incredibly adaptable ancestors to the modern varieties.
Cui received his undergraduate degree in agricultural science, and moved from his home country of China to America to complete a master's in molecular biology and biochemistry at Georgetown. He is currently working on his Ph.D. in translational plant science here at Virginia Tech. Cui’s interest in the tomato comes from its prevalence as a major world crop, and his research focuses on the genetic basis of tomato stress response traits.
Near his desk sit four rows of plants in boxes, each marked with ID tags that determine which treatment they get. Multiple wild tomato populations sampled from the Andes region of South America are used to investigate differences in gene expression across drought and herbivore stress. The stress conditions are simulated under controlled conditions in the laboratory. Some go with only 25 percent of their water needs, some are sprayed with a chemical mixture to simulate herbivore stress, and some get both. Genetic material is harvested and stored in a freezer that sits at -85 degrees Celsius. The material is then studied by using next generation sequencing. This sequence analysis will attempt to answer which genes are responsible for these reactions. Dissecting the patterns of molecular evolution among defense-related traits across past environmental changes, Cui’s study will provide insights on wild tomatoes’ ability to buffer against predicted climate change.
The hope is that commercial varieties of tomatoes could be genetically modified to include traits that would better tolerate drought conditions caused by global climate change. Unlocking the tomato’s adaptability to make it a hardier crop will help it survive this environmentally challenging time. But there are also other applications. Even if we stop climate change, and start to reverse its effects, there will still be droughts and deserts. There are places that humans will go that will have totally alien climates, and they will take tomatoes with them. The plant will still have obstacles to overcome; thus, better understanding its origins as the incredibly adaptable plants of South America can take the tomato further than it’s ever gone before.
Article written by Valerie K. McLean while participating in ENGL 4824: Science Writing in Spring 2017 as part of a collaboration between Fralin and the Department of English at Virginia Tech.