The seed-specific transcription factor DPBF2 modulates the fatty acid composition in seeds.

Triacylglycerol (TAG), an ester derived from glycerol and three fatty acids (FAs), is synthesized during seed development and controlled by transcriptional regulation. We examined the mechanism regulating the FA composition of developing seeds. The seed-specific () transcription factor was upregulated by (). DPBF2 showed transcriptional activity in yeast and localized to the nucleus in Arabidopsis protoplast cells. The Arabidopsis homozygous T-DNA mutant and transgenic lines overexpressing of 2 using a seed-specific phaseolin promoter in wild-type (WT) Arabidopsis and in showed similar FA composition profiles in their seeds. Their 18:2 and 20:1 FA contents were higher, but 18:1 and 18:3 contents were lower than that of WT. Transcript levels of (), , (), , (), and () are increased in -overexpressing seeds. Besides, and were upregulated by DPBF2, LEC1-LIKE (L1L), and NUCLEAR FACTOR-YC2 (NF-YC2) transcriptional complex based on tobacco protoplast transcriptional activation assay. These results suggest that DPBF2 effectively modulates the expression of genes encoding FA desaturases, elongase, and acyl-editing enzymes for modifying the unsaturated FA composition in seeds.