Among all other legumes, soybeans are protein powerhouses, providing a key protein source for humans and livestock around the world. Now, after 30 years, scientists at the University of Illinois have identified a gene with the largest impact on seed protein in soybeans.

In 1992, then-graduate student Brian Diers published the first seed protein map for soybeans and identified the region of the genome where the gene might be located. Three decades and many technological advances later, the publication of two soybean genomes nail down Glyma.20G85100, a gene without a known function but closely related to "clock and circadian timing" genes.

Like most genes, Glyma.20G85100 comes in multiple forms or alleles. Depending on the allele found in a particular soybean line, seed protein content can be high or low. And, as it turns out, most commercial soybean lines contain the low-protein allele. According to Diers, the high-protein allele has a deleterious effect on yield so elite varieties bred for high yield generally have the low-protein form. The team hoped that the gene would be involved in nitrogen fixation or nitrogen metabolism, but the gene appears to be part of the soybean plant's circadian machinery.

Matt Hudson, co-author of the study said, "It could be that the gene is involved in moving photosynthesis products into the seed or it could be some completely unrelated pathway. It's weird, and we really don't know."

For more details, read the article in ACES News.