Virus-induced gene silencing shows that LATE FLOWERING plays a role in promoting flower development in soybean

Virus-induced gene silencing (VIGS) is a useful tool to investigate the role of genes particularly in hard-to-transform plant species via the Agrobacterium-mediated genetic transformation process. Soybean is one of the most important crops for the food and protein source, but its low transformation efficiency makes it hard to identify the functions of genes of interest. Here, we adopted tobacco ringspot virus (TRSV)-based VIGS systems and examined the role of a LATE FLOWERING (GmLATE) gene in soybean. Because TRSV induces symptoms affecting leaf senescence and development, we screened soybean genotypes and selected a genotype, named Aram, which shows resistance to TRSV symptoms while is susceptible to TRSV-induced gene silencing. The TRSV-based silencing of GmLATE in soybean showed suppressed flower development with decreased expression of genes related to flowering. These results suggest that GmLATE plays a role in promoting flower development in soybean, which is different from its role as a floral repressor in Arabidopsis. Our results show the novel function of GmLATE and demonstrate that TRSV-based VIGS system can be used as a tool to study genes involved in flowering in soybean.