Is a milder mustard on the way?

The mustards, broccolis and cabbages of the world share a distinct and bitter taste. Some consider the flavor of cruciferous plants their strongest attribute. But even in India and China, where these members of the Brassica genus have been cultivated for more than 4,000 years, scientists have sought to tone down the chemical compounds responsible for their pungent flavor. As it turns out, the same compounds that make them bitter also make them toxic at some levels.

Now, researchers on three continents -- including biologists from Washington University in St. Louis -- have mapped the crystal structure of a key protein that makes the metabolites responsible for the bitter taste in Brassicas. A study published this month in the journal The Plant Cell is the first snapshot of how the protein evolved and came to churn out such diverse by-products in this agriculturally significant group of plants.

The results could be used along with breeding strategies to manipulate crop plants for nutritional and taste benefits.

The work is the result of a collaboration among Naveen Bisht, a scientist at the National Institute of Plant Genome Research in New Delhi, India; Joseph Jez, a plant biologist at Washington University; and Jonathan Gershenzon of the Max Planck Institute for Chemical Ecology in Jena, Germany.

"All the Brassicas -- be they Indian mustard, broccoli or Brussels sprouts -- make these pungent, sulfur-smelling compounds, the glucosinolates," Jez said. The compounds have long been recognized as the plants’ defense against pests.

The insight gained in the new study is important step toward mustering a milder mustard or building a bitter-free broccoli. But will it help us eat our greens?

"This paper is an excellent example of the potential of fundamental research to have an impact in agriculture," said Engin Serpersu, a program director in NSF’s Division of Molecular and Cellular Biosciences, which funded the research.