Fig. 3

Identification of the FtUFGT3 gene associated with kaempferol-3-O-rutinoside content. a Manhattan plot for GWAS on kaempferol-3-O-rutinoside content (KC) in the full population. The dashed line indicates the threshold −logP = 5. The red arrow indicates the SNP in FtUFGT3. b Local Manhattan plot (top) and linkage disequilibrium heat map (bottom) for the gene associated with KC. c Schematic representation of genes in the association region. I, FtPinG0100123000; II, FtPinG0100123100; III, FtUFGT3; IV, FtPinG0100123600; V, FtPinG0100123800; VI, FtPinG0100123900; VII, FtPinG0100124100. d Schematic representation of the FtUFGT3 genomic sequence. Exons and introns are represented by boxes and lines, respectively. The blue line represents the promoter and 3′ UTR. The causal SNP locates in the promoter − 1303 bp that is marked by a black line. Hap1, haplotype 1; Hap2, haplotype 2; Hap3, haplotype 3. e Expression of genes from c during seed development excluding II. DPA, days postanthesis. f Box plots show KC in three haplotypes (Hap.). *P < 0.05, ***P < 0.001, Student’s t test. g Relative expression levels of FtUFGT3 in different buckwheat accessions of Hap.1 and Hap.3. Data are mean ± SD. h KC in Tartary buckwheat transgenic hairy roots overexpressing FtUFGT3, mixed by five lines. Data are mean ± SD. ***P < 0.001, Student’s t test. i Enzyme assay of FtUFGT3 in vitro. Up for reaction product of MBP-FtUFGT3 protein and kaempferol standard; middle for kaempferol standard; below for kaempferol-3-O-glucoside standard. Kae., kaempferol