Scientists Identify a Brake Gene for Seed Oil Control in Soybean

Soybean (Glycine max) is one of the most important oilseed crops worldwide, and its seed oil content directly dictates its economic value and industrial applications. Soybean oil accounts for over half of the global oilseed production, and serves as a vital source of both edible oil and industrial raw materials, making it significant economic value. However, the biosynthesis of oil accumulation is finely regulated by numerous factors, and the regulatory mechanisms underlying oil accumulation await further elucidation.

 

A research team led by Prof. ZHANG Jinsong from the Institute of Genetics and Developmental Biology of the Chinese Academy of Sciences uncovers a brake gene for oil control in soybean, with implications for improving oilseed crop productivity and addressing global demands for sustainable vegetable oil sources.

 

The study, published in Plant Biotechnology Journal (DOI: 10.1111/pbi.70348) on September 4, 2025, reveals a novel molecular network, GmERFA-GmNFYA-GmbZIP123/GmZF392, which integrates multi-dimensional regulation (transcriptional and protein-protein interaction networks) to explain natural variation in soybean oil content, and deepens the understanding of the connections among different oil regulators.

 

Through RNA-seq analysis and screening for the interacting proteins of a positive oil regulator GmNFYA, researchers identified an AP2/ERF-type transcription factor GmERFA, which is located in nucleus and acts as a negative regulator of oil accumulation. GmERFA is steadily expressed during the soybean seed development, and increased sharply at the later maturation stage. The researchers further utilized gene-editing technology to generate double mutant soybeans targeting GmERFA and its homologs. All the gmerfa/b mutants produced larger seeds with more weight and more oil.

 

The importance of GmERFA-GmNFYA-GmbZIP123/GmZF392 network lies in its regulation of the balance and selection of energy substances such as sugars, oils, and proteins during soybean seed development. Sugars serve as critical precursors for the biosynthesis of oils and proteins. In the regulatory network, GmNFYA activates downstream genes GmbZIP123 and GmZF392, which regulate sugar transport and metabolism while promoting the expression of genes related to oil biosynthesis, thereby enhancing seed oil accumulation.

 

On the other hand, GmERFA acts as a negative regulator of oil biosynthesis. It directly suppresses the expression of GmbZIP123 and GmZF392 or interfere with the transcriptional activation ability of GmNFYA by interacting with it. GmERFA effectively reduces sugar transport to the seeds and inhibits sugar metabolism, thereby suppressing oil biosynthesis. As GmERFA expression rises sharply during the S6-S7 stages of seed development, its molecular role functions as a 'braking mechanism' to suppress oil biosynthesis in later developmental stages. This process also signals the seed's transition into dehydration and maturation.

 

Given the negative correlation between oil and protein content, increasing GmERFA expression to inhibit oil biosynthesis can adjust the relative proportions of oil and protein. Therefore, GmERFA is also a key target in soybean breeding process aimed at developing varieties with different oil and protein contents. It is projected that the global demand for vegetable oil will double by 2050. The molecular network GmERFA-GmNFYA-GmbZIP123/GmZF392 identified in this study provides a critical genetic theoretical foundation and innovative breeding strategies for developing high-oil soybean varieties.

 

Considering that the research team led by Prof. ZHANG Jinsong has identified several transcription factors including positive regulators GmDOF4/11, GmbZIP123, GmMYB73, GmDREBL, GmNFYA, GmZF351 and GmZF392, as well as the present negative regulator GmERFA, it is not clear why soybean needs multi-factors for oil control. It is possible that these factors may work at different stages and/or processes singly or combinatorially for a proper source/sink allocation and a suitable oil/protein level, producing a seed for better propagation and survival to the environments.

 

This work is supported by the STI 2030-Major Projects, the National R & D project and the National Natural Science Foundation of China.

 

 

Contact:

Prof. ZHANG Jinsong

Institute of Genetics and Developmental Biology, Chinese Academy of Sciences

Email: jszhang@genetics.ac.cn