Transcriptome -wide approach to identifying differentially expressed genes involved in low seed protein content in western-Canadian soybeans, Glycine max

Soybean [Glycine max (L.) Merr.] is among the most important agronomic crops in Canada with widespread uses in human consumption, animal feed, and biotechnology. The capacity to fix atmospheric nitrogen into biologically available forms gives soybean an important role in sustainable agricultural practices (i.e., reducing the need for nitrogen fertilizers). Understanding the effect environmental variation has on gene expression in Canadian soybean is valuable for developing sustainable agricultural systems. The Canadian Grain Commission has reported lower seed protein content from soybeans grown in western Canada compared to eastern Canada, regardless of genotype. This project will uncover key genes responsible for differences in seed protein content across Canada.
Here we use a transcriptome-wide approach to identify differences in expression of genes which contribute to seed protein content, and to study the effect of environmental variation on geographically-dependent gene expression (West vs East). Ten soybean lines ranging low to high in seed protein content are growing in four locations over four years across western and eastern Canada. Using RNA sequencing, differential transcript analysis of each line is compared between West and East to determine key genes responsible for lower seed protein content in western soybeans. Analysis of first year data has identified three genes encoding cupins and 93 lipid-related genes. This research will provide novel information about the best geographically-fitting soybean cultivars to grow across Canada’s growing regions. The findings of this research will be used to develop allele-specific markers, assisting breeding programs to develop high protein soybean cultivars for western Canada.