Sometimes, the way forward is to look back. This may be the case with soybeans, whose wild relatives have higher levels of beneficial fatty acids.
Most health experts promote foods with essential fatty acids--substances that cannot be produced in the body. One of these, plant-sourced omega-3 alpha-linolenic acid (ALA), is in chia and flax seeds, as well as soybeans.
"Essential fatty acids can have multiple positive health benefits, including reduction of cardiovascular disease and improved cognitive function," says Jeong-Dong Lee. Lee is a professor in the School of Applied Biosciences, Kyungpook National University in the Republic of Korea.
In many Asian countries, the diet includes relatively high amounts of soybeans and soy products like tofu, soy sprouts, and soybean paste. Soybean oil is a key source of ALA. However, ALA oxidizes rapidly, leaving an undesirable flavor. Breeding methods have tried to reduce ALA content—until recently.
"Increasing the ALA or omega-3 fatty acid concentration in soybean seed oil has become a major goal in food-grade soybean breeding," Lee says.
Lee thinks soy's wild relatives may lead the way. Wild soybeans mostly grow in a broad area including China, Japan, and Korea. They have adapted to a variety of conditions. The result, crop scientists found, is wild soybeans have higher genetic diversity than their cultivated cousins do. By recycling this diversity, wild soybeans genetics can improve the properties of cultivated soybeans.
"Wild soybeans generally have higher ALA concentration than cultivated soybean," Lee says. In general, cultivated soybeans contain 8–10% ALA. Wild soy can contain more than twice that amount.
Lee's study identified wild soybean varieties with the highest ALA percentages. In addition to higher ALA levels, Lee also tested for stability in different growth conditions. Scientists provided the lab plants different soil types and fertility levels, and varying amounts of moisture, salt concentrations, and temperatures.
The researchers extracted seeds from each sample and analyzed the fatty acid content by standard laboratory tests. The results identified several types of wild soybeans with high ALA concentrations that were stable across all environmental conditions tested.
Lee's group is currently studying specific areas of wild soy genome—the complete collection of genes—to pinpoint those areas responsible for high ALA production. This will assist in identifying a particular property of the crop, such as high ALA or tolerance to heat, salt, insects, disease and other environmental challenges.
Lee's work may have a deadline. "Human activities are infringing on and destroying the natural habitats of wild soybeans," Lee says. His research will help preserve the genetic diversity and useful features of wild soybeans, aiding the improvement of future cultivated varieties.
Lee's research is published in Crop Science. The Next-Generation BioGreen 21 Program for Agriculture and Technology Development (Plant Molecular Breeding Center, Project No. PJ01109201), Rural Development Administration, Republic of Korea, provided funding.