Cultivating better plants

To avoid widespread famine and malnutrition, the world must double current food production by 2050, and do so in the face of climate-driven pressures. That is why a key WIBHC thrust focuses on plant seeds, the source of more than two-thirds of calories currently consumed globally.

“Not only is it essential that scientists learn how to enhance the resiliency of predominant food crops, we must learn to increase seed-productivity of ‘orphan’ crops that are already able to better withstand heat, drought, and changing soil conditions,” says Mary Gehring, Whitehead Institute Member and Landon T. Clay Career Development Chair. Gehring’s lab has previously shown that the fundamental mechanisms of plant reproduction and seed development are controlled epigenetically — by information outside of the DNA sequence. Using that knowledge and the methods developed in those investigations, she and her colleagues are aiming to engineer plants that are stress-resistant, more nutritious, and higher yielding.

In parallel, they are working to develop methods to ensure that plants can pass on beneficial traits from one generation to the next. One desirable trait is hybrid vigor — the phenomenon where hybrid plants are more vigorous than either parent. “Unfortunately, most improvements in crop plants caused by hybridity are lost after a single generation. That means new hybrid seeds must be purchased annually, which severely limits broader cultivation of hardy varieties,” explains Gehring, who is also associate professor of biology at MIT. But she believes it is possible to instill plants with heritable hybrid vigor: To that end, her team is developing a method for clonal seed production — that is, creating seeds that are genetically identical to the parent and can pass desirable traits from generation to generation. “Engineering clonal seed production will be technically difficult,” Gehring notes, “but achieving it would revolutionize agriculture.”

If society is to limit the long-term impact of climate change, we must reduce atmospheric carbon, the key driver of increased global temperatures. While eliminating fossil fuels is key, bioengineering plants to better sequester carbon could also help substantially. “Huge amounts of carbon are fixed in living plants then released into the atmosphere when they die and decay,” explains Jing-Ke Weng, Institute Member and associate professor of biology at MIT. “It is estimated that global woody biomass emits eight times as much carbon as fossil fuels.”

While it is an extraordinarily ambitious goal, Weng believes that humanity could achieve negative carbon emission by replacing 15 percent of current global woody vegetation with plants bioengineered to accumulate decay-resistant biomass. The approach could be more easily scaled than other carbon sequestration technologies, and the resulting decay-resistant material could be used to create value-added products.

Carbon fixed in plants is primarily stored as biopolymers that are subject to decay. But plants could be bioengineered to increase production of decay-resistant biopolymers, thereby sequestering more carbon. One such polymer, sporopollenin, normally accounts for a tiny fraction of plants’ biomass. But Weng and Jonathan Weissman, Whitehead Institute Member and professor of biology at MIT, are working to develop the scientific knowledge and new technologies needed to bioengineer plants that hyperaccumulate sporopollenin.

Weissman, who is also Whitehead Institute’s Landon T. Clay Professor and an Investigator of the Howard Hughes Medical Institute, is renowned for helping create tools for genome editing and controlling the expression of human genes. “For the carbon sequestration project, our team is developing methods to systematically define gene function in plants, building on similar tools we’ve developed and are using in mammalian systems,” he explains.

“Jing-Ke and I anticipate that the core technologies developed in these projects would be readily translatable to a variety of plant species in diverse environments around the world.”

Read more about the goals of — and some of the scientific projects comprising — the Whitehead Initiative on Biology, Health, and Climate Change.