Decoding the soybean genome

Scientists have sequenced the genome of the soybean plant, Glycine max, an important agricultural crop. As reported in the journal Nature1, the sequencing was accomplished through collaborative work between scientists in the United States and at the RIKEN Plant Science Center in Yokohama.

Soybeans are an important food source for humans, since they are used to produce foods such as soy sauce and tofu, as well as to make vegetable oil for cooking. But soybeans also are an important component of animal feed throughout the world, and play a key ecological role in taking nitrogen from the air and putting it back into the soil.

From their analysis of the 20 chromosomes of the soybean plant, the researchers predict that there are over 46,000 genes, more than double the number of genes in humans. Consistent with the known genome duplication of the soybean at two different points in its evolution, the geneticists identified many blocks of genes, corresponding to three-quarters of the soybean’s 46,000 genes. These blocks were found more than once across the genome, including across different chromosomes.

The existence of multiple copies of a gene within a genome may allow for genetic diversity if some of those copies mutate in such a way that they take on novel functions, or so that their expression can be controlled separately under different environmental conditions. As an example of this, the researchers found double the number of fatty acid synthesis genes in the soybean genome than in Arabidopsis, a flowering plant that has not undergone genome expansions. This may explain why soybeans are such a good source of cooking oil, while Arabidopsis is not.

As soybean plants are sensitive to disease, such as Asian soybean rust, which lead to losses in agricultural yield that adversely affect the world food supply, farmers need disease-resistant varieties of this important crop. Soybean varieties that have high nutritional content, hardier seeds and plants, and easier reproduction would also be agriculturally attractive.

“The genome sequence opens the door to crop improvements that are needed for sustainable human and animal food production, energy production and environmental balance in agriculture worldwide,” write the authors.

The corresponding author for this highlight is based at the Integrated Genome Informatics Research Unit, RIKEN Plant Science Center

Journal information

1. Schmutz, J., Cannon, S.B., Schlueter, J., Ma., J. Mitros, T., Nelson, W.,Hyten, D.L. Song, Q., Thelen, J.J. Cheng, J. et al. Genome sequence of the palaeopolyploid soybean. Nature 463, 178–183 (2010)