Grains for Change

Peggy Lemaux wants to change the world through agriculture. It’s a drive that has guided her work as a plant geneticist from the very beginning, one she traces to her childhood in northwestern Ohio. “Because of my upbringing on a small farm, and my close relationship with my grandfather, who was responsible for the farm, I made it my goal to do something positive for agriculture,” she says.

Recent developments on our planet have only added to her sense of urgency. Chief among them is climate change, with its twin threats to agriculture: longer, more severe droughts and heat waves on one hand; wetter, more intense rainstorms on the other. In many regions of the world with undernourished and rapidly growing populations, climate-fueled crop losses can have devastating consequences.

“While you might have hoped in the past to just depend on evolution to help plants figure out how to survive huge floods or a long time without water, I don’t think evolution can keep up now,” Lemaux says. “Our opportunity as geneticists is to help tweak evolution, to take our knowledge and help plants figure out how to deal with changes in the climate.”

Lemaux and colleagues at UC Berkeley, UC Agriculture and Natural Resources, and both the U.S. Department of Energy’s Joint Genome Institute and the DOE’s Pacific Northwest National Laboratory have recently used modern genetic technologies to learn more about how sorghum, a cereal crop valued around the world for its high tolerance for heat and drought, developed the means to survive arid conditions.

Native to Africa and Australia, sorghum is ranked fifth in total production among cereal crops globally and is a staple food crop in much of the developing world. It remains green and yields grain under conditions that render corn and wheat brown, brittle, and barren. A paper published in December in the journal Proceedings of the National Academy of Sciences provides possible clues to its success, offering the first detailed look at how sorghum switches off many genes—some involved with photosynthesis—at the first sign of water scarcity, then turns them back on when water returns.

For nearly three decades, Lemaux has led groundbreaking research intended to improve the performance and quality of cereal crops. As a Cooperative Extension specialist in the Department of Plant and Microbial Biology (PMB)—a role that bridges the gap between the university and the public— she blends bench and real-world science in pursuit of more nutritious, robust, and resilient staple crops to feed the world.

While her mission is laudable, progress has not been easy. Among her research tools is what some see as a Pandora’s box: genetic engineering, in which modifications are introduced into the genome of an organism to add desirable traits or remove undesirable ones.

It’s an approach to crop improvement that Lemaux says holds significant technological promise. Over the years, her successes—in the lab, at least—have piled up. She was part of the first team to genetically engineer corn during the early days of her career, at DeKalb Genetics. She also helped develop, with PMB professor Bob Buchanan, barley that germinates quickly; a variety of wheat that is hypoallergenic and one that resists preharvest sprouting; sorghum that’s easier to digest than the conventional kind; and a tool for using rice and other cereal grains to make large quantities of commercial products.

With the exception of this last development, now employed by a Colorado company to make medicinal products, none of Lemaux’s major findings have made it into the field. This is due in large part to fears among regulators and the public that genetically engineered crops may be unsafe to consume (a worry not well supported by evidence, Lemaux believes) or pose a threat to the environment (a risk that can be mitigated through proper management, she says). “Because of the intensive backlash to genetic engineering, few of the things that we developed have gone anywhere,” says Lemaux. “The seeds are all down in the basement.”

For her latest research on sorghum, Lemaux has taken a different approach. Both the December paper and one published in 2018—which describes how sorghum plants produce metabolites in their roots to summon aid from soil bacteria during times of drought stress— are part of an ongoing research project called EPICON (Epigenetic Control of Drought Response in Sorghum) that Lemaux helped develop, in part to avoid the conflicts surrounding traditional genetic engineering. Performed over multiple growing seasons in fields in the Central Valley, the work to date has not involved the engineering of genes—only the observation of how genes help sorghum survive drought. The field study is the first of its kind, providing a detailed look at the plant’s entire development and response to drought, from germination to harvest.

“One of the reasons I got involved in EPICON was that it was not about doing genetic engineering to create a product but, rather, focused on using those tools to understand drought tolerance,” Lemaux says. She is hopeful that the novel observational approach will produce results that lead to real-world applications.

Another EPICON study, published in Nature Communications  in January, describes a different aspect of sorghum’s interaction with certain microbes in the soil—specifically, important root-associated fungi that supply the plant with nutrients and minerals. The study shows that drought causes changes in the dynamics of which fungi colonize the leaves and roots, and it could provide insight into how researchers could introduce beneficial microbes or suppress harmful ones. With the end of EPICON fast approaching, Lemaux and her colleagues are responding to a call from the DOE for new five-year proposals to continue and expand the research. If the team can gain further insight through that effort into exactly how sorghum survives drought, then perhaps its findings can inform approaches to helping other plants survive in the same way. This may include traditional crossbreeding or, potentially, genome-editing technologies like CRISPR, a newer, highly precise approach to genetic modification that has so far eluded strict regulation in agriculture.

As Lemaux has shifted her attention from the production of genetically modified crops to less controversial observational studies, she has simultaneously expanded her efforts at outreach. Communicating about research with nonscientists has always been essential to her work, and she has given hundreds of lectures and interviews.

In 2015, with colleagues from UC Davis and UC San Diego, Lemaux launched CLEAR, or Communication Literacy and Education for Agricultural Research, a program designed to help UC Berkeley students at all levels practice communicating with the public about science. Backed by a grant from the UC Office of the President’s Global Food Initiative, CLEAR provides funding for supplies, local travel, and other small expenses to support volunteer student-led science communication efforts.

One of its signature projects has been hosting a monthly table at the downtown Berkeley Farmers’ Market, where CLEAR participants interact with the public on topics ranging from soil microbiomes to food waste. Students have also spoken at science-themed events at local pubs and are developing an exhibit on CRISPR ethics at the Lawrence Hall of Science. And in one impressive case, a CLEAR fellow created a curriculum around genome editing that reached more than 600 Bay Area and Los Angeles high schoolers last year.

To date, around 70 students have participated in CLEAR. For some, like Becky Mackelprang, PhD ’17 Plant Biology, the program has offered a path away from bench science and toward a career in science communication or policy. After completing her PhD, Mackelprang continued working with Lemaux and CLEAR as a postdoctoral scholar for a year and a half.

“A lot of grad students want to use their scientific expertise for something other than scientific research,” Mackelprang says. “I saw science being communicated in ways that were too complex for the general public or without the creativity that might generate an excitement for science.”

Mackelprang next completed an American Association for the Advancement of Science mass media fellowship with the outlet Ensia. Recently, she began a position at a nonprofit that specializes in science policy, where she’ll continue to put her communication skills to work.

One subject she expects to confront often, much as her mentor Lemaux has over the past three decades, is genetic engineering—and particularly the newer genome-editing techniques like CRISPR. She says she hopes to contribute to the discussion around how best to realize the full benefits of the technology while mitigating any potential downsides.

Yet if past experience is any indication, the issue is unlikely to be resolved soon, Lemaux notes. She’s concerned that currently permissive attitudes toward new methods of plant-gene editing may one day flip, stifling more research and findings.

“If that happens, the real losers will be those in less developed countries,” she says. “These new technologies could prove enormously beneficial for communities who don’t have alternative approaches that might be available in more developed countries.”