A seed germination transcriptomic study contrasting two soybean genotypes that differ in terms of their tolerance to the deleterious impacts of elevated temperatures during seed fill

Authors: Gillman, Jason; BIEVER, JESSICA - University Of Missouri; YE, SONGQING - University Of Missouri; SPOLLEN, WILLIAM - University Of Missouri; GIVAN, SCOTT - University Of Missouri; LYU, ZHEN - University Of Missouri; JOSHI, TRUPTI - University Of Missouri; Smith, James - Rusty; FRITSCHI, FELIX - University Of Missouri

Submitted to: BMC Research Notes
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/7/2019
Publication Date: 8/19/2019
Citation: Gillman, J.D., Biever, J.J., Ye, S., Spollen, W.G., Givan, S.A., Lyu, Z., Joshi, T., Smith, J.R., Fritschi, F.B. 2019. A seed germination transcriptomic study contrasting two soybean genotypes that differ in terms of their tolerance to the deleterious impacts of elevated temperatures during seed fill. BMC Research Notes. 12:522. https://doi.org/10.1186/s13104-019-4559-7.
DOI: https://doi.org/10.1186/s13104-019-4559-7

Interpretive Summary: Soybean seed yield and quality can be negatively impacted by elevated temperature during seed development. We had previously identified an un-adapted and low-yielding line which has remarkable resistance to damage from elevated temperatures as compared to elite, high-yielding lines. In this study, soybean seed were produced under temperature stress or a control non-stress field location. We then evaluated gene expression during seed germination for both a temperature-tolerant and temperature-sensitive line. This generated a unique set of gene expression data specific for early seed germination, which can be leveraged for basic research. In addition, our results confirmed and extended previous research that showed high antioxidants and higher tolerance to oxidative damage, in seeds of the tolerant line. These results will guide ongoing breeding efforts to create more stress-tolerant soybean lines with acceptable seed yield.

Technical Abstract: Objective: Soybean seed development is negatively impacted by elevated temperatures during seed fill, which can decrease seed quality and economic value. Prior germplasm screens identified an exotic landrace able to maintain ~95% seed germination under stress conditions that reduce germination dramatically (>50%) for typical soybean seeds. Seed transcriptomic analysis was performed for two soybean lines (a heat-tolerant landrace and a typical high-yielding adapted line) for dry, mature seed, 6-hour imbibed seed and germinated seed. Seeds were produced in two environments: a typical Midwestern field and a heat stressed field located in the Midsouth soybean production region. Results: Transcriptomic analysis revealed 23-30K expressed genes in each seed tissue sample, and Differentially Expressed Genes (DEGs) with = 2-fold gene expression differences (at q-value <0.05) comprised ~5-44% of expressed genes. Gene Ontology (GO) enrichment analysis on DEGs revealed enrichment in heat-tolerant seeds for genes annotated for general and temperature-specific stress, as well as protein-refolding. DEGs were also clustered in modules using Weighted Co-Expressed Gene Network Analysis, which were examined for enrichment of GO Biological process terms. Collectively, our results provide new and valuable insights into this unique form of genetic abiotic stress tolerance and to soybean seed physiological responses to elevated temperatures.