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ARS Home » Plains Area » Fort Collins, Colorado » Center for Agricultural Resources Research » Agricultural Genetic Resources Preservation Research » Research » Publications at this Location » Publication #410442

Research Project: Curation and Research to Safeguard and Expand Collections of Plant and Microbial Genetic Resources and Associated Descriptive Information

Location: Agricultural Genetic Resources Preservation Research

Title: Evaluating seed longevity: Use of RNA integrity to characterize variation within species of legume grain

Author
item Tetreault, Hannah
item REDDEN, ROBERT - Australian Grains Genebank
item FLEMING, MARGARET - Michigan State University
item Hill, Lisa
item ZINGERMAN, ZOE - Oak Ridge Institute For Science And Education (ORISE)
item WHITEHOUSE, KATHERINE - Australian Grains Genebank
item NORTON, SALLY - Australian Grains Genebank
item Walters, Christina

Submitted to: Seed Science Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/16/2024
Publication Date: 12/12/2024
Citation: Tetreault, H.M., Redden, R.J., Fleming, M., Hill, L.M., Zingerman, Z., Whitehouse, K., Norton, S., Walters, C.T. 2024. Evaluating seed longevity: Use of RNA integrity to characterize variation within species of legume grain. Seed Science Research. https://doi.org/10.1017/S0960258524000072.
DOI: https://doi.org/10.1017/S0960258524000072

Interpretive Summary: Genebanks rely on germination tests to monitor seed health and detect mortality during storage of diverse germplasm collections. These assays are the preferred method used by the seed community to answer the question of whether seeds are/are not viable. However, seeds deteriorate with time in a sigmoidal pattern, and germination assays cannot be used to predict when the abrupt change in seed health will occur. Genebanks are charged with replenishing the sample before it dies, and therefore continually test stored samples to detect small changes in health that may portend imminent death. The repeated testing depletes the sample by consuming thousands of seeds. However, the sample could be lost altogether if seeds die between testing intervals that are too broad. Previous work has shown that RNA molecules fragment during storage before changes in seed health can be detected and that the change in the RNA integrity number (RIN) is linear with time. Here we collaborate with scientists at the Australian Grains Genebank to use a legacy experiment that they started in 2003. We ask whether the pattern of RNA fragmentation can be used to distinguish fast and slow aging seed lots within a species. The experiment used ten varieties each of pea, chickpea and lentil that were stored at either 20 or 2°C for 20 years. The rate that seeds of different varieties died during storage correlated with changes in RIN measurements, suggesting that RIN is an effective marker of aging rate. This work also provides insight into variation in seed longevity among varieties within each crop.

Technical Abstract: Seed genebanks must maintain collections of healthy seeds and regenerate accessions before seed viability declines. Seed shelf life is often characterized at the species level; however large, unexplained variation among genetic lines within a species can and does occur. This variation contributes to unreliable predictions of seed quality decline with storage time. To assess variation of seed longevity and aid in timing regeneration, ten varieties of pea (Pisum sativum L.), chickpea (Cicer arietinum L.) and lentil (Lens culinaris Medikus subsp. culinaris) from the Australian Grains Genebank were stored at moderate temperature (20°C) and moisture (7-11% water, RH ~30%) and deterioration was assessed by yearly germination tests for 20 years. Decline in germination was fit to a sigmoidal model and the time corresponding to 50% germination (P50) was used to express seed longevity for each genetic line. The feasibility of using RNA fragmentation to assess changed seed health was measured using RNA integrity number (RIN) from RNA extracted from seeds that were stored for 13 and 20 years. Seed lots of these legume grains that maintained high survival throughout the 20 years (i.e., they aged slower than other lines) had higher RIN than samples that degraded faster. RIN was lower in embryonic axes compared to cotyledons in the more deteriorated samples, perhaps indicating axes exhibit symptoms of aging sooner than cotyledons. Overall, RIN appears to be associated with longevity indicators of germination for these legumes and indicates RIN decline can be used to predict the longevity threshold to optimize viability monitoring.