Thirty-five years ago, when CALS bacteriologist Winston Brill and his colleagues set out to exploit science’s newfound ability to manipulate genes to confer new traits on crop plants, the technology was, literally, a shot in the dark.
Working in a facility in Middleton, just west of Madison, Brill and his team blasted plant cells using a gene gun—a device that fired microscopic gold beads laden with DNA.
The idea was to introduce foreign genes that could confer new abilities on the plants that would ultimately be grown from the altered cells. First as Cetus of Madison, Inc., later as Agracetus and still later as a research and development outpost of Monsanto Company, the Middleton lab was, by all accounts, a hub of plant biotechnology innovation.
“Agracetus was the first in the world to engineer soybean, first in the world to engineer cotton, first in the world to field-test a genetically engineered plant,” recalls Brill, who was recruited by Cetus to establish the lab in the early 1980s. “Thus, the Madison area and the UW influence led to historically important events.”
In December 2016, the $10 million,100,000-square-foot facility—a warren of labs, greenhouses and growth chambers—was donated to UW–Madison by Monsanto to become the Wisconsin Crop Innovation Center (WCIC).
The hope, according to agronomy professor Shawn Kaeppler BS’87—now WCIC’s director—is that the center will add to its string of plant biotechnology achievements as one of just a few public facilities in the country dedicated to plant transformation, where genetically modified plant cells are taken from tissue culture and regenerated into large numbers of complete fertile plants.
The advent of the WCIC “is an unprecedented opportunity to add capabilities and capacity we couldn’t afford otherwise,” says Kaeppler, an expert on corn. Its acquisition by UW–Madison, he and others note, comes at an opportune time as powerful new techniques in synthetic biology are poised to make the development of plants with new or improved traits much more than a shot in the dark with a gene gun.
WCIC will function very much like a core facility, providing cell culture, phenotyping and plant transformation services for researchers at UW– Madison and other universities. It is also coming online at a time when the need for such resources is acute.
“There is a recognized need nationally,” explains agronomy professor Heidi Kaeppler BS’87, an expert in plant transformation who is serving as WCIC’s transformation technology director. “There are just a few public facilities around the U.S. and demand is outpacing the abilities of those facilities. It is a bottleneck.”
For researchers like bacteriology and agronomy professor Jean-Michel Ané, a member of the WCIC scientific advisory board, the new center means he will be able to devote more time to exploring such things as the genetic interplay that occurs when plants and bacteria collude to draw nutrients from the air through the act of nitrogen fixation.
Nitrogen-fixing plants such as soybean, alfalfa and clover are staples of modern agriculture. They are essential to the crop rotation practices that prevent exhaustion of soil from crops such as corn. Ané and many other scientists have long dreamed of engineering the ability to fix nitrogen into plants like corn to transcend the need for expensive and environmentally harmful chemical fertilizers.
However, engineering complex traits such as nitrogen fixation in plants that don’t have that innate ability is a monumental scientific and technological undertaking. To begin with, there are two organisms—the plant and a bacterium—working cooperatively. Each has its own genome, and many different genes from each organism are in play to accommodate the act of drawing life-sustaining nutrients from the air.
To confer that trait on corn, for example, is an exercise far more complicated than tinkering with one or a few genes, notes Ané. “The goal is to create maize that has this association. However, modifying a single gene will not be sufficient,” he says. “We modify many genes at a time. There is a lot of trial and error. We need to try many combinations.”
Those combinations come about in the lab as scientists alter individual plant cells by adding or subtracting genes of interest. Today, scientists can harness new techniques such as CRISPR– Cas9—a fast, cheap and accurate genome editing tool—and potent new cloning technologies that allow scientists to easily assemble multiple DNA fragments and their assorted genes into novel sequences.
Even with potent new tools like CRISPR–Cas9, engineering plants is a big, difficult task. A gene needs to be dropped in the right place on the genome and be in association with the right “promoters,” segments of DNA that initiate gene transcription, the first step toward expressing a new gene in an organism. Once plant cells are genetically altered, they must be transformed into large numbers of actual plants for further testing in the lab and, ultimately, the field. It is essential to know, for example, that the new genetic construct is stable, that the new genes are passed from generation to generation, and what effects they may have on plant growth or yield.
The promise of WCIC, Ané believes, will be the opportunity to work through all of those steps more efficiently and cost-effectively, and carry projects from the lab to the field much faster.
“We can focus on really doing science instead of growing plants,” Ané says. “We can now make genetic constructs very quickly. Within a month we can make hundreds of constructs. The limiting aspect is plant transformation. However, the scale of transformation we can do at WCIC allows us to think seriously about applying synthetic biology to plants.”
To begin with, WCIC is providing plant transformation services for corn, soybean and sorghum, big commercially important crop species. But Shawn Kaeppler envisions WCIC playing a role, as well, with crop plants that have not yet risen to the top of commercial research agendas.
To date, commercial interest has focused primarily on just a handful of traits—insect and herbicide resistance—in a handful of widely planted crops. Uncharted territory, Kaeppler says, exists in the full range of crop plants and their many different traits.
A ready example is switchgrass, a native perennial that is under the microscope at the Great Lakes Bioenergy Research Center (GLBRC), a U.S. Department of Energy- funded multi-institutional research center headquartered on the UW–Madison campus. The grass is seen as a potential feedstock for converting its biomass to liquid fuel. However, efficient conversion of plant materials to energy remains a challenge, and plant genetics will play a big role in refining the traits that will make that possible.
“WCIC will help lead us to the next generation of crop breeding and plant genetics,” explains Kate VandenBosch, the dean of CALS, referencing, broadly, the genetic makeup of the crop plants in play. “Scientific agencies at the federal level have invested a lot in understanding genomes, but we still have a lot of work to do to understand how those genes function.”
Indeed, genetic sequencing technologies have advanced to the point where new plant genomes are sequenced with increasing regularity. The genomes of crop plants like watermelon, cucumber, potato, soybean, wheat, corn and many others have been sequenced, but as VandenBosch notes, exploring those sequences to identify the genes that govern plant traits is an unexplored frontier.
Shawn Kaeppler’s own research, for example, is a window to both the complexity and opportunity that lurk in the genomes of plants. One of his interests is the complex of genes—involving anywhere from tens to hundreds of genes—that governs the root architecture of corn. Knowing more about the combination of genes that directs the plant to send shoots into the soil, it might one day be possible to engineer a plant that can send its roots deeper into the earth, providing farmers with a hedge against drought.
“Fifty to 70 percent of all maize genes are expressed in roots,” Kaeppler says. “Some control processes in all parts of a plant, and some specifically control root development and response to environmental stimuli.”
A gene of interest for Kaeppler and his team is one that influences root angle. “Altering root angle even five to 10 degrees can dramatically increase the rate that roots get deep in the soil,” as well as how much root biomass a plant lays down at depth, he explains.
Identifying those candidate genes and mutations of those genes means they can be selected and manipulated in the laboratory to generate plants with different root structures. At WCIC, those plants can be grown in quantity, their new qualities studied and, if promising, tested in the field. The goal, of course, is to provide a practical outcome that is useful to growers.
In plant science, numbers matter. The more plants you can grow to test a new genetic combination, the better, as there are so many variables in play.
“In many aspects of science, doing things on a large scale is critical,” says biochemistry professor Rick Amasino, an expert on flowering in plants. “To have WCIC in our capability is great. Large-scale transformation opens up a lot of possibilities.”
Amasino, who is also a member of WCIC’s scientific advisory board, views the center as an important new national resource. Individual labs, he explains, do not have the same capacity.
“This has the potential to be on a scale greater than any other university’s,” Amasino says. “Individual labs can’t generate the hundreds or thousands of transgenic plants needed to fully test certain hypotheses. Labs around the country and, hopefully, around the world can now do experiments they couldn’t otherwise do. There are so many opportunities out there.”
This story was originally published in the Summer 2017 issue of Grow magazine.