Abstract:

FLK(Flowering Locus KH Domain)plays an important role in flowering time regulation,and its function has been characterized in Arabidopsis.In order to identify the function,GmFLK was isolated from soybean Williams 82 and the encoded protein was predicted by structural and bioinformatics analysis.The subcellular localization of this protein was examined in tobacco leaves and the expression pattern of this gene was analyzed in soybean.The results showed that the GmFLK was 6 806 bp in length,containing 6 exons and 5 introns.The CDS was 1 341 bp,encoding 446 amino acids.The molecular weight of the protein was 47.031 ku,and the isoelectric point was 5.46.GmFLK protein contained three structures,α-Helix,β-Strand and Coil,which had 24.44%,14.80% and 60.76%,respectively.Phylogenetic analysis revealed that GmFLK had a close relationship with Glyma.03g248200,followed by Medicago Medtr7g115340,Arachis hypogaea ArahyQL2VNI, ArahyUPVY9X,and Arabidopsis AtFLK.Subcellular localization analysis showed that GmFLK protein was expressed in the nucleus,cytoplasm and cell membrane.GmFLK promoter contained 10 types of cis-acting elements,and 6 types were considered to be involved in photoperiod response.In addition,GmFLK was expressed in flower,leaf,root,seed and stem,and GmFLK showed relative high expression levels in leaf and seed,and relative low levels in flower.The expression patterns of GmFLK under long day and short day photoperiod conditions were similar.However,GmFLK showed different expression levels throughout the day and night,and exhibited low expression level after 4 h,lights-on,and high expression level after 0 and 12 h,lights-on.In summary,our study reveals that GmFLK might be a key factor involved in flowering time regulation.

Key words: Soybean, GmFLK, Gene clone, Subcellular localization, Gene expression