South Dakota State University associate biology and microbiology professor Wanlong Li assesses the growth of two-week-old wheat seedlings. Photo: Emily Weber

While we’re most enamored with CRISPR’s ability to edit human genomes, the powerful tool is not selective—it can edit other genomes as well. In one such study, researchers are using CRISPR to expand the size and weight of wheat kernels in the hope of increasing overall wheat yield.

Although humans consume more than 500 million tons of wheat per year, overall production is decreasing as farmers continue to move toward crops that are more profitable. Increasing yield is one way to ensure wheat becomes a desirable, profitable crop again. But, that takes some genetic manipulation.

Fundamentally, this can be achieved by improving wheat’s photosynthesis. For example, wheat uses less than 1 percent of sunlight to produce the parts we eat, compared to maize’s 4 percent efficiency and sugarcane’s 8 percent efficiency. Even increasing wheat’s photosynthetic efficiency from 1 percent to 1.5 percent would allow farmers to increase their yields on the same amount of land, using no more water, fertilizer or other inputs.

Through a new Department of Agriculture grant and working with the International Wheat Yield Partnership Program, South Dakota State University’s Wanlong Li and Iowa State’s Bing Yang seek to apply CRISPR to wheat’s photosynthesis problem.

First, the researchers will identify the genes that control grain size and weight in bread wheat using a rice genome model. Then, they will use CRISPR to edit out each negatively regulating gene—which will serve the two-fold purpose of removing it from the genome, as well as having it available to study.

Li and Yang will create 30 constructs that target 20 negative genes. Partners from the University of California Davis Plant Transformation Facility will then produce 150 first-generation plants for the researchers to study. When all is said and done, the researchers should be able to identify which mutations yield larger seeds—and thus, increased yields.

One of the benefits of this process is the end product will not be considered genetically modified organisms.

“When we transfer one of the CRISPR genes to wheat, it’s transgenic. That then produces a mutation in a different genomic region. When the plants are then self-pollinated or backcrossed, the transgene and the mutation are separated,” Li explained. “This is null transgenic.”

In fact, the USDA has approved this technique in other organisms, and Yang has already utilized it in unrelated research to develop bacterial blight-resistant rice.

Ultimately, these yield-increasing mutations, along with the markers to identify the traits, can be transferred to other varieties of wheat, such as durum, spring and winter wheat.

South Dakota State University is one of seven universities nationwide to receive funding to develop new wheat varieties as part of the National Institute of Food and Agriculture’s International Wheat Yield Partnership Program. Li’s focus on CRISPR and photosynthesis efficiency is just one approach to the problem. Other research projects from the organization include: testing genes to boost spike development; optimizing canopy architecture to increase carbon capture and conserve nitrogen; and using selected genes from other species to increase biomass and yield, among others.

A distinguishing feature of the International Wheat Yield Partnership Program is it’s “hub”—a massive parcel of land in Mexico that is used for the evaluation of innovations, and subsequent development pipeline.