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May 6, 2020

MSU faculty explores factors that make both potatoes and science teachers tick

Whether you are a seasoned researcher or a student teacher, it is never too late or too early to develop new investigative and pedagogical skills. But if you are a potato — one of the most important and nutritious food crops in the world — timing is everything.

Like the human sleep/wake cycle, potato physiology is regulated by internal circadian rhythms sensitive to the earth’s 24-hour oscillation of light (see video clip on right), but changes linked to potato domestication wound potato clocks faster than expected.

With support from a four-year, $2.5 million Mid-Career Award in Plant Genome Research, or MCA-PGR, from the National Science Foundation, Eva Farré, associate professor in MSU’s Department of Plant Biology in the College of Natural Science will lead a highly interdisciplinary team of Michigan State University scientists to investigate what makes successful domesticated potatoes and successful science teachers tick.

“Climate change is altering more than the weather — crop production regions and species ranges will shift north, altering their daylength cycles,” Farré said.

Historically, potatoes have already experienced a similar shift. In the mid-1500s, sailors brought potatoes to the Canary Islands from South America. When farmers began to move those potatoes further north, they became unwitting tuber horologists, artificially selecting certain phenotypes that survived northern latitudes with longer days while retaining the faster circadian clocks of their wild ancestors.

“For many plant species, adaptation to the long summer days of the northern hemisphere is associated with a slower circadian clock,” Farré explained. “Grown far away from the equator, you would expect domesticated potatoes to also have a slower clock, but all cultivated potatoes we have measured have a fast circadian clock.”

Understanding the circadian rhythm at more northern latitudes and locating the alleles responsible for the clock genes will help Farré’s team optimize the growth of this important tuber under different daylengths.

Previous studies by co-principal investigator, or co-PI, Robin Buell, MSU Foundation Professor of plant biology and director of the Plant Resilience Institute at MSU, confirmed circadian clock genes are, in fact, under genetic selection. Still, scientists have yet to definitively find a causal link between specific potato genes and circadian clocks, partly because potatoes are tetraploids — they keep four copies of their genes.

“Potatoes are genetically complicated, so to pinpoint what allele causes a particular phenotype is a challenging problem,” said Farré, who noted that members of the team discovered how to create a simpler, diploid potato they will utilize in the research. “My lab will use three potato genotypes — two wild varieties and one cultivated—to run physiological analyses of photosynthesis rates and metabolite content at different times of the day in order to correlate them with gene expression differences.”

The team will also expand phenotyping and genotyping to hundreds of wild and cultivated potatoes.

“Ideally, we want to phenotype 200 different varieties that originate from different locations in South America with different latitudes and altitudes,” Farré said. “A larger sample size will allow us to verify potential correlations between phenotypes and their environment as well as associate gene variants with the speed of the circadian clock.”

In addition to providing funds to train Farré, one postdoc and one graduate student in transcriptomics, or measuring gene expression under different conditions, the grant will also provide training opportunities for future science teachers.

“One challenge for future science teachers is that they rarely have opportunities to engage in disciplinary practices that are now the norm for K-12 students,” said co-PI David Stroupe, associate professor in the MSU College of Education and associate director for STEM Teacher Education in the CREATE for STEM Institute at MSU. “In this project, four future teachers will have the exciting opportunity to be immersed in Dr. Farré’s laboratory, help conduct potato research and then teach an undergraduate science course.”

“I wanted to reach out to Dr. Stroupe to improve skills for teaching science experiments in schools,” Farré said. “Providing a lab experience will help define the research activities and teaching models that work best to learn the skills they need as teachers.”

Other MSU co-PI’s on the grant are: David Douches and Addie Thompson in the Department of Plant, Soil and Microbial Sciences and Arjun Krishnan, who holds joint appointments in the Department of Computational Mathematics, Science and Engineering and the Department of Biochemistry and Molecular Biology.

Click here to find out more about this grant and the NSF MCA-PGR. 

By: Val Osowski

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