Differential Gene Expression Profiling in Soybean to Investigate the Relationship Between Nitrogen Fixation and Drought Stress

Legume crops, such as Glycine max, have extensive water requirements. Drought is a major agricultural constraint in soybean production. Climate projections predict drier global environments, thus leading to increased concerns of successful soybean harvests in the future. To combat future losses, sustainable solutions are necessary. A better understanding and greater diversity of drought-tolerance genes are sought to complement already implemented and ongoing genetic and molecular-physiological efforts.

In this experiment, we assessed differences in gene expression profiles in high and low N₂ fixing genotypes in different tissues. We used two soybean genotypes with opposing N₂ fixation phenotypes (high and low). The two genotypes were exposed to three different water availability treatments: well-watered (WW), moderate water stress (S1), and severe water stress (S2). RNA was collected and sequenced using Illumina Hi-Seq (100 bp single-end reads). RNAseq reads were aligned back to the reference genome for differential expression (DE) analysis. By comparing and contrasting N₂ fixation at the three different water availability regimes, we seek to improve knowledge of tissue specific N₂ fixation capabilities during drought.