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Turning Up the Heat in Battle Against Chili Pepper Root Rot

Posted by Scott Elliott, National Institute of Food and Agriculture in Research and Science
Jun 17, 2014
Peppers are part of the Solanaceae family, which includes potato, tomato, and eggplant.
Peppers are part of the Solanaceae family, which includes potato, tomato, and eggplant.

This post is part of the Science Tuesday feature series on the USDA blog. Check back each week as we showcase stories and news from the USDA’s rich science and research portfolio.

Good news for those who crave culinary heat.  From the chili pepper aficionados who “eat fire” to those who prefer more subtle flavors, researchers have found a way to help ensure that more of their favorite foods will be available on store shelves.

Scientists at University of California–Davis have identified a candidate gene that encodes natural resistance to Phytophthora capsici, a fungus-like pathogen that causes root rot in peppers.  P. capsici is a major limiting factor to chili production worldwide.

Led by Dr. Allen Van Deynze, director of research at UC Davis’ Seed Biotechnology Center, doctoral candidate Zeb Rehrig used an Agriculture and Food Research Initiative grant from the USDA’s National Institute of Food and Agriculture (NIFA) to conduct extensive screening and testing that pinpointed the location of the resistance gene.

Managing ongoing projects at both the UC Davis lab and others in a university/industry consortium, Rehrig screened 31,000 gene sequences – far above the 1,000 normally screened for this type of a test.  This expansive screening allowed him to identify regions associated with disease resistance, sequence the candidate genes, and verify them in multiple pepper populations and breeding lines.  “The way it came together highlights the power of good genetics, plant breeding, and genomics,” Van Deynze said.  Their work is published this month with a July cover story in the journal The Plant Genome.

While this research was specific to peppers, it may have application with other important agricultural crops.  Peppers are part of the Solanaceae family, which includes potato, tomato, and eggplant.  “Our work suggests that the gene we identified confirms broad resistance to P. capsici and has been effective against downy mildews in tomato, lettuce, and spinach – across very different plant families,” Van Deynze said.

As successful as the project has been so far, there is another aspect that has yet to bear fruit, although Van Deynze says it looks promising.  “We were able to fully integrate the (project) results and breeding lines into K-12, undergraduate, and graduate education through our collaboration with the UC-Davis Student Farm program,” he said.  In three years, they have reached more than 2,000 K-12 students from diverse ethnic and income backgrounds, giving each hands-on experience to spark their interest in the pepper, plant breeding, and plant science in general.

With consumption of peppers growing by double digit percentages every year, the world may need those new scientists to keep up with production demands.

Category/Topic: Research and Science