By homing in on the mysterious potato genome and its tuber - the edible portion - researchers are unveiling the secrets of the world's most important non-grain food crop.
July 14, 2011
By homing in on the mysterious potato genome and its tuber – the edible portion – researchers are unveiling the secrets of the world’s most important non-grain food crop.
MSU AgBioResearch plant biologist C. Robin Buell is part of an international research team that is mapping the genome of the potato. In the July 10, 2011, issue of Nature, the team revealed that it had accomplished its goal, opening the way to improve the food source’s elusive genome. Co-author of the paper was MSU AgBioResearch scientist Dean Della Penna, professor of biochemistry and molecular biology.
The potato is a member of the Solanaceae, an economically important family that includes tomatoes, peppers, eggplants, petunia and tobacco. According to the U.S. Potato Board, potatoes are the leading vegetable crop in the United States, with a total production of 41.3 billion pounds. The U.S. potato consumption is 126 pounds per person per year. Despite the importance of the tubers, the evolutionary and developmental mechanisms of how they grow and reproduce remained elusive – until now, Buell said.
“This is the first plant with a tuber to be sequenced,” she said. “It will still take researchers awhile to use the genome information to improve its agronomic traits, such as improved quality, yield, drought tolerance and disease resistance. But our most recent research will accelerate efforts on improving potato varieties and help bring a better potato to the farmer.”
Even though potatoes have flourished on every continent except Antarctica, they are susceptible to pests, pathogens and inbreeding depression (passing on undesirable traits that lead to weaker offspring). Ireland’s 19th century potato famine is one illustration of how the collapse of such an important crop can affect a large population.
In 2009, the research team was able to identify the potato’s genetic blueprint. During the past two years, the team has worked to determine which genes are expressed in specific tissues, such as the tuber versus the flowers, to better understand the growth and development of the plant's tuber. The team focused on two types of potatoes, which provided data on a wide spectrum of the potato’s genomic diversity.
“Since our initial release of the sequence in 2009, we have improved the quality, identified and analyzed the genes, and analyzed the genetic basis for the biology of the potato and its tuber,” Buell said. “Our analysis revealed that the potato genome contains 39,000 protein coding genes, of which 90 percent of the chromosomal positions are now known.”
Additionally, researchers were successful in identifying possible mechanisms by which inbreeding depression occurs. Together, the results could help potato breeders reduce the amount of time it takes to develop new varieties. That typically takes around 15 years.
“Given the high consumption of potato tubers in the U.S. diet, it plays an important role in human nutrition,” Della Penna said. “The potato genome has provided important insights into the biochemical pathways present and operating in developing tubers. This knowledge should accelerate efforts to enhance the levels of essential nutrients in abundantly consumed crop.”
The Potato Genome Sequencing Consortium, an international team of 39 scientists from 14 countries, began work on the potato genome project in 2006. The complete sequence is estimated to be 840 million, about one-quarter the size of the human genome. Buell plans to expand the research to include more varieties of potatoes as well as other members of the Solanaceae family.
In addition to funding from MSU AgBioResearch, Buell and Della Penna’s research is supported by the U.S. Department of Agriculture and the National Science Foundation.