Soybean gene SW14 plays a dual role in enhancing crop yield and quality

Lisa Lock
scientific editor

Robert Egan
associate editor

Soybean (Glycine max L. Merr.), a globally critical oilseed and economic crop, stands as a primary source of high-quality protein for human consumption and animal feed alike.
Among the agronomic traits shaping its productivity, seed size and the balance between oil and protein content are deemed pivotal—making the identification of genes governing these traits and the clarification of their molecular mechanisms essential for advancing high-yield, high-quality soybean varieties via molecular design breeding.
Through genome-wide association studies (GWAS) and quantitative trait loci (QTL) mapping, a research team, led by Prof. Hou Xingliang from the South China Botanical Garden of the Chinese Academy of Sciences, pinpointed a Nuclear Factor-YA (NF-YA) gene located on chromosome 14, which they named Seed Weight 14 (SW14).
Functional analysis revealed that SW14 exerts a dual regulatory role: it positively boosts seed weight and protein content while negatively regulating oil content—all without impacting other key agronomic traits of the soybean plant. The work is in the journal Nature Communications.
Further investigations uncovered the molecular mechanism behind SW14's action. The gene interacts with GmLEC1a/b—soybean homologs of Leafy Cotyledon1 (LEC1), a core regulator of seed development. This interaction disrupts the formation of a non-canonical NF-Y complex, which normally consists of GmLEC1, GmNF-YC2, and GmbZIP67. By breaking down this complex, SW14 inhibits the transcriptional activation process mediated by GmLEC1—a process critical to seed development.
Additional genetic analysis provided further insights: a superior allele of SW14, designated SW14H3, was found to have undergone artificial selection during the domestication of soybeans. The researchers noted that this allele holds significant potential for improving soybean yield in agricultural applications.
More information: Chunyu Zhang et al, Natural allelic variation in SW14 determines seed weight and quality in soybean, Nature Communications (2025).
Journal information: Nature Communications
Provided by Chinese Academy of Sciences