Advanced genome-editing techniques have been used to create a strain of wheat resistant to a destructive fungal pathogen—called powdery mildew—that is a major bane to the world’s top food source, according to scientists at one of China’s leading centers for agricultural research.
To stop the mildew, researchers at the Chinese Academy of Sciences deleted genes that encode proteins that repress defenses against the mildew. The work promises to someday make wheat more resistant to the disease, which is typically controlled through the heavy use of fungicides. It also represents an important achievement in using genome editing tools to engineer food crops without inserting foreign genes—a flashpoint for opposition to genetically modified crops.
The gene-deletion trick is particularly tough to do in wheat because the plant has a hexaploid genome—that is, it has three similar copies of most of its genes. That means multiple genes must be disabled or the trait will not be changed. Using gene-editing tools known as TALENs and CRISPR, the researchers were able to do that without changing anything else or adding genes from other organisms.
“We now caught all three copies, and only by knocking out all three copies can we get this [mildew]-resistant phenotype,” says Caixia Gao, who heads a gene-editing research group at the State Key Laboratory of Plant Cell and Chromosome Engineering at the Institute of Genetics and Developmental Biology in Beijing.
A paper describing the results appears in Nature Biotechnology.
“This is very, very interesting; it is quite an accomplishment to knock out all three genes at the same time,” says Xing-Wang Deng, who heads a joint research center for plant molecular genetics and agricultural biotech at Peking University and Yale. “And this could be considered as a nontransgenic technology, so that can be very significant. I hope the government would not consider this transgenic, because the end result is no different than a natural mutation.”
There are currently no commercially planted varieties of genetically modified wheat anywhere in the world. And while many farmers are clamoring for access to such strains, genetically modified wheat remains highly controversial. Indeed, it’s not clear is whether Gao’s promising strain of wheat will make it out of the greenhouses in Beijing.
Gao says she has filed a global patent on the technology, suggesting it could be licensed. But there are no field trials planned yet. While China has greatly increased investments in basic biotech research, including for genetically modified crops, no new field trials of genetically engineered plants have been approved in more than a year as the government tries to mollify public concern over GMOs.
Gao says gene editing can provide very efficient tools for basic research and crop improvement, including in complex organisms like wheat. “And it can be without the controversy,” she says.