Coupling VIGS with short and long-term stress exposure to understand the Fiskeby III iron deficiency stress response

Authors: O`Rourke, Jamie; Graham, Michelle

Submitted to: International Journal of Molecular Sciences
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/26/2022
Publication Date: 12/30/2022
Citation: O'Rourke, J.A., Graham, M.A. 2022. Coupling VIGS with short and long-term stress exposure to understand the Fiskeby III iron deficiency stress response. International Journal of Molecular Sciences. 24(1).Article 647. https://doi.org/10.3390/ijms24010647.
DOI: https://doi.org/10.3390/ijms24010647

Interpretive Summary: Stress caused by iron deficiency is a major limitation for crop production in the upper Midwestern United States. Iron deficiency results in yield loss, which translates to financial loss for farmers. Fiskeby III is a soybean variety with a high level of resistance to multiple abiotic (nonliving) stresses, including iron deficiency. Virus induced gene silencing (VIGS) is a technique used to turn down expression of a specific gene so that the effects on the organism can be used to characterize the gene’s function. This experiment examined gene expression profiles in leaves and roots of Fiskeby III plants in which our candidate gene of interest was silenced relative to control plants. Silenced plants were sampled either 1 day or 7 days after moving to iron-stress conditions, but were the same age at the time of tissue harvest. Gene expression analyses of these samples confirmed the importance of our candidate gene in the Fiskeby III iron stress response. Additionally, like other stress tolerant soybean varieties, Fiskeby III responded quickly to abiotic stress but utilized novel genes within genetic pathways previously identified to provide stress tolerance. These new genes can be leveraged by breeders to improve abiotic stress tolerance in soybean and other crop species.

Technical Abstract: Yield loss due to abiotic stress is an increasing problem in agriculture. Soybean is a major crop for the upper Midwestern United States and calcareous soils exacerbate iron deficiency for growers, resulting in substantial yield losses. Fiskeby III is a soybean variety uniquely resistant to a variety of abiotic stresses, including iron deficiency. Previous studies identified a MATE transporter (Glyma.05G001700) associated with iron stress tolerance in Fiskeby III. To understand the function of this gene in the Fiskeby III response to iron deficiency, we coupled its silencing using virus induced gene silencing with RNAseq analyses at two timepoints. Analyses of these data confirm a role for the MATE transporter in Fiskeby III iron stress responses. Further, they reveal that Fiskeby III induces transcriptional reprogramming within 24 hours of iron deficiency stress, confirming that like other soybean varieties, Fiskeby III is able to quickly respond to stress. However, Fiskeby III utilizes novel genes and pathways in its iron deficiency response. Identifying and characterizing these genes and pathways in Fiskeby III provides novel targets for improving abiotic stress tolerance in elite soybean lines.