Differential gene expression of higher latitudes in soybean

Over the past two decades soybeans grown in western Canada (higher latitudes) have persistently
had lower seed protein than those grown in eastern Canada. To understand the discrepancy in
seed protein content between soybean grown in higher latitudes compare to the lower ones, RNAseq
and differential expression analysis have been investigated. Ten soybean genotypes, ranging
from low to high in seed protein content, were grown in four locations across eastern (Ottawa)
and western Canada. Differential expression analysis revealed 34 differentially expressed genes
encoding Glycine max Sugars Will Eventually be Exported Transporters (GmSWEETs), including
paralogs GmSWEET29 and GmSWEET34 (AtSWEET2 homologs) that were consistently upregulated
across all ten genotypes in each of the western locations over three years. GmSWEET29 and
GmSWEET34 are likely candidates underlying the lower seed protein content of western soybeans.
GmSWEET20 (AtSWEET12 homolog) was downregulated in locations with higher latitudes land
may also play a role in lower seed protein content. These findings are valuable for improving
soybean agriculture in regions with higher latitudes (i.e., Western Canada growing regions),
establishing more strategic and efficient agricultural practices.