Using a molecular technique known as the comet assay, researchers tracked oxidative DNA damage and repair in seeds stored for 2, 5, and 12 years under cold dry genebank conditions. Their findings revealed that while aging naturally deteriorates seed quality over time, seeds with higher initial quality demonstrated stronger resilience.
Genebanks play a vital role in preserving crop diversity and ensuring global food security by safeguarding seeds for future generations. Traditional African vegetables (TAVs), including African eggplant, are rich in micronutrients but often overlooked in mainstream agriculture. The World Vegetable Center's genebank in Tanzania maintains large collections of these crops under cold dry conditions to support conservation and breeding programs. However, even under ideal storage conditions, seeds undergo slow deterioration due to oxidative stress, leading to declines in viability and genetic stability. Until now, little was known about how African eggplant seeds age in storage or the extent to which DNA damage may affect their viability and usefulness.
A study (DOI: 10.48130/seedbio-0024-0003) published in Seed Biology on 25 March 2024 by Jonas Nickas’s team, Sokoine University of Agriculture, carries critical implications for genebank conservation practices and future crop improvement efforts across sub-Saharan Africa.
To assess the impact of long-term storage on seed quality, researchers evaluated seed viability, vigor, and genetic integrity of African eggplant genotypes stored under cold-room genebank conditions (10 °C) for 2, 5, and 12 years. Seed viability and germination parameters were measured through germination tests, while DNA damage and repair were assessed using the comet assay, which quantifies the percentage of tail DNA in both imbibed and non-imbibed seeds. The results revealed a significant decline in seed viability with increasing storage duration across all genotypes, with the 12-year-old DB3 seeds showing the steepest drop—from 68.0% to 11.3%. Genotypes such as RW-AE-7, UG-AE-16, and Tengeru White also experienced viability losses ranging from 16.5% to 28%. Additionally, the initial seed quality was influenced by environmental conditions during seed production, especially temperature, which had a negative effect on viability. Seed vigor indicators like germination energy and seed vigor index I (SVI) significantly decreased in older seeds, particularly in DB3 and Tengeru White, while 1000-seed weight also declined with storage time. The comet assay results confirmed increased DNA damage in older seed lots, with 12-year-old RW-AE-7 and DB3 seeds exhibiting the highest mean tail intensities. Notably, lower tail intensities generally correlated with higher germination energy, although exceptions were observed, indicating that additional factors may influence DNA repair and seed performance. Overall, these findings demonstrate that long-term storage under cold conditions leads to viability and genetic integrity loss, especially in seed lots with lower initial quality, emphasizing the need for genotype-specific monitoring and management in genebanks.
The findings underscore the importance of maintaining high initial seed quality and monitoring storage duration to preserve seed performance in genebanks. By linking DNA damage with seed vigor and viability, the study introduces the comet assay as a practical, low-cost molecular tool for early detection of seed deterioration. This tool could guide timely regeneration of aging seed stocks, reducing the risk of genetic erosion. The data also support the use of seed weight as a simple, non-destructive metric for predicting seed health during long-term conservation and distribution.
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References
DOI
10.48130/seedbio-0024-0003
Original Source URL
https://doi.org/10.48130/seedbio-0024-0003
Funding information
This research was financially supported by the 'Taiwan-Africa Vegetable Initiative (TAVI)' project and the One CGIAR Initiative on Fruit and Vegetables for Sustainable Healthy Diets (FRESH)’s Work Package 2. Funding for the genebank of traditional African vegetables is provided by strategic long-term donors to the World Vegetable Center: Republic of China (Taiwan), UK aid from the UK government, United States Agency for International Development (USAID), Australian Center for International Agricultural Research (ACIAR), Germany, Thailand, Philippines, Korea, and Japan.
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.