Analysis of promoter activity reveals that GmFTL2 expression differs from that of the known Flowering Locus T genes in soybean

Abstract Regulation of flowering is one of the key issues in crop yield. The Flowering Locus T ( FT ) gene is a well-known florigen, which integrates various signals from multiple flowering-regulation pathways to initiate flowering. We previously reported that there are at least six FT genes ( GmFTL1 – 6 ) in soybean displaying flowering activity. However, the individual functions of genes GmFTL1 – 6 remain to be identified. In this study, we cloned the GmFTL2 promoter ( GmFTL pro ) from soybean ( Glycine max ) cultivar Tianlong 1 and analyzed its motifs bioinformatically and its expression patterns using both a transgenic approach and quantitative RT-PCR (qRT-PCR). In GmFTL pro :: GUS transgenic lines, GUS signals were enriched in cotyledons, hypocotyledons, pollen, embryos, and root tips in a photoperiod-independent manner. qRT-PCR confirmed the GUS reporter results. Our results suggest that GmFTL2 expression is regulated by developmental and tissue-specific clues and plays roles in seedling establishment and the development of microgametophytes, embryos, and roots.