Mining Fiskeby III and Mandarin (Ottawa) expression profiles to understand iron stress tolerant responses in soybean

Authors: O`Rourke, Jamie; Morrisey, Michael; MERRY, RYAN - University Of Minnesota; ESPINA, MARY - University Of Minnesota; LORENZ, AARON - University Of Minnesota; STUPAR, ROBERT - University Of Minnesota; Graham, Michelle

Submitted to: International Journal of Molecular Sciences
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/10/2021
Publication Date: 10/13/2021
Citation: O'Rourke, J.A., Morrisey, M.J., Merry, R., Espina, M.J., Lorenz, A.J., Stupar, R.M., Graham, M.A. 2021. Mining Fiskeby III and Mandarin (Ottawa) expression profiles to understand iron stress tolerant responses in soybean. International Journal of Molecular Sciences. 22(20). Article 11032. https://doi.org/10.3390/ijms222011032.
DOI: https://doi.org/10.3390/ijms222011032

Interpretive Summary: Yield loss due to iron deficiency stress is a problem throughout the major soybean growing regions of the US. Fiskeby III is a soybean cultivar with a high level of resistance to multiple abiotic stresses, including iron deficiency. Conversely, Mandarin(Ottawa) is highly susceptible and suffers severe yield loss when exposed to stress. This experiment compared the expression of all genes expressed in leaves and roots of Fiskeby III and Mandarin(Ottawa) grown in normal and iron stress conditions. We then turned off the expression of gene we predicted was responsible for iron stress tolerance in Fiskeby III and again compared the expression of all genes in normal Fiskeby III and in Fiskeby III where the predicted iron stress gene was turned off. These analyses found Fiskeby III uses novel mechanisms to respond to iron stress and confirmed the identify of a key iron stress response gene. These findings can be leveraged to improve abiotic stress tolerance in soybean and other crop species.

Technical Abstract: The soybean (Glycine max L. merr) genotype Fiskeby III is highly resistant to a multitude of abiotic stresses, including iron deficiency, incurring only mild yield loss during stress conditions. Conversely, Mandarin(Ottawa) is highly susceptible to disease and suffers severe phenotypic damage and yield loss when exposed to abiotic stresses such as iron deficiency, a major challenge to soybean production in the northern Midwestern United States. Using RNA-seq, we characterize the transcriptional response to iron deficiency in both Fiskeby III and Mandarin(Ottawa) to better understand abiotic stress tolerance. Previous work by our group identified a quantitative trait loci (QTL) region on chromosome 5 associated with Fiskeby III iron efficiency [1] indicating Fiskeby III utilizes iron deficiency stress mechanisms not previously characterized in soybean. We targeted 10 of the potential candidate genes in the Williams 82 genome sequence associated with the QTL using virus induced gene silencing. Coupling virus induced gene silencing with RNA-seq, we identified a single high priority candidate gene with a significant impact on iron deficiency response pathways. Characterization of the Fiskeby III responses to iron stress and the genes underlying the chromosome 5 QTL provides novel targets for improved abiotic stress tolerance in soybean.