Saturated ceramides unlock the secrets of soybean seed germination

By integrating transcriptome analysis, lipid profiling, and gene overexpression studies, scientists have uncovered how these lipids regulate key hormone pathways, offering promising strategies to enhance soybean yield and seed quality.

Seed germination is the foundational stage of a plant’s life cycle, dictating the success of crop establishment and yield. For soybean (Glycine max), a globally important oil and protein crop, rapid and uniform germination is vital. However, environmental stresses and hormonal imbalances can disrupt this process. While sphingolipids—complex membrane lipids—are known to regulate plant stress and growth responses, their role in seed germination has remained unclear. Due to these challenges, a deeper understanding of how sphingolipids influence seed germination is urgently needed.

A study (DOI: 10.48130/seedbio-0025-0006) published in Seed Biology on 17 April 2025 by  Ming Luo & Fan Xu’s team, Southwest University, opens new avenues for improving soybean germination and yield under stress conditions by linking specific sphingolipids to hormonal signaling and gene regulation.

To investigate the role of sphingolipids in soybean seed germination, researchers applied 5 μM of C24 phytoceramide (t18:0/24:0) to seeds during imbibition and conducted a comprehensive time-course analysis integrating transcriptomics, lipidomics, and gene co-expression network modeling. Germination assays revealed that exogenous C24 phytoCer markedly accelerated seed germination: after 24 hours, treated seeds achieved a germination rate of 48.3%, significantly higher than the 29.2% seen in controls, and reached 85.8% by 36 hours—surpassing mock-treated seeds by over 30%. RNA-Seq analysis at 0, 6, 12, and 24 hours post-imbibition yielded high-quality transcriptome data, identifying over 32,000 expressed genes and more than 22,000 differentially expressed genes (DEGs) by 24 hours. Notably, 7,581 DEGs were shared across all time points and grouped into two expression modules: one positively correlated with germination and enriched in pathways like fatty acid biosynthesis and glycolysis, and another negatively correlated, associated with photosynthesis and ABA signaling. Concurrently, sphingolipidomics revealed that levels of simple saturated sphingolipids—including ceramide d18:0/16:0, ceramide d18:0/22:0, and phytoCer t18:0/24:0—rose significantly during germination, while complex sphingolipids declined. Co-expression network analysis confirmed strong correlations between these lipids, germination rates, and the turquoise gene module. Further validation through overexpression of GmSLD1, a gene involved in ceramide desaturation, led to elevated ABA levels, reduced GA/ABA ratios, and pronounced seed dormancy, confirming the inhibitory role of desaturated ceramides. Together, these results demonstrate that saturated sphingolipids actively promote soybean germination by modulating hormonal pathways, particularly by enhancing gibberellin signaling and suppressing ABA accumulation.

The identification of lipid signatures that regulate seed dormancy and germination has broad agricultural implications. Seed treatments using saturated ceramides, or genetic modification of lipid biosynthesis genes, could become tools for improving crop establishment and productivity—especially in regions prone to climate stress. Beyond soybean, these insights may apply to other oilseed crops with similar dormancy challenges.

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References

DOI

10.48130/seedbio-0025-0006

Original Source URL

https://doi.org/10.48130/seedbio-0025-0006

Funding information

This study was supported by the National Natural Science Foundation of China (Grant No. 32172059), the Fundamental Research Funds for the Central Universities (Grant No. SWU-XDJH202315), the Chongqing Technology Innovation and Application Development Special Key Project, China (Grant No. cstc2021jscx-gksbX0011), and the Collection, Utilization and Innovation of Germplasm Resources by Research Institutes and Enterprises of Chongqing, China (Grant No. cqnyncw-kqlhtxm).

About Seed Biology

Seed Biology (e-ISSN 2834-5495) is published by Maximum Academic Press in partnership with Yazhou Bay Seed Laboratory. Seed Biology is an open access, online-only journal focusing on research related to all aspects of the biology of seeds, including but not limited to: evolution of seeds; developmental processes including sporogenesis and gametogenesis, pollination and fertilization; apomixis and artificial seed technologies; regulation and manipulation of seed yield; nutrition and health-related quality of the endosperm, cotyledons, and the seed coat; seed dormancy and germination; seed interactions with the biotic and abiotic environment; and roles of seeds in fruit development. Seed Biology publishes a wide range of research approaches, such as omics, genetics, biotechnology, genome editing, cellular and molecular biology, physiology, and environmental biology. Seed Biology publishes high-quality original research, reviews, perspectives, and opinions in open access mode, promoting fast submission, review, and dissemination freely to the global research community.