Page 315 - ebook

[F. Others] F-14

The function of DPBF2 transcription factor on the regulation

of fatty acid composition

Inyoung Kim¹, Sujeong Jeong², Hyun Uk Kim¹,²*

¹Department of Molecular Biology, Sejong University, Seoul 05006, Korea, ²Department of Bioindustry and

Bioresource Engineering, Sejong University, Seoul 05006, Korea

Triacylglycerol (TAG) is synthesized during seed maturation and controlled by the LEAFY COTYLEDON2 (LEC2),

FUSCA3 (FUS3) and ABSCISIC ACID INSENSITIVE3 (ABI3) known as master regulators of seed maturation in
transcriptional regulation. In this study, we identified the seed-specific DC3 PROMOTER-BINDING FACTOR2 (DPBF2)

transcription factor activated by the regulation of LEC2. In leaf tissue, DPBF2 is upregulated by LEC2 expression and
downregulated in developing seed of lec2-1 mutant. In dpbf2-1 homozygous T-DNA mutant seeds, the 18:2 and

20:1 fatty acid content was higher, the 18:1 and 18:3 content was lower than in wild-type (WT) seeds. While the
transcript levels of FATTY ACID DESATURASE3 (FAD3), LYSOPHOSPHATIDYLCHOLINE ACYLTRANSFERASE1 (LPCAT1),

and LPCAT2 were decreased in developing seeds of the dpbf2-1 mutant, seed-specific overexpression of DPBF2
using phaseolin promoter increased the transcript levels of FAD2, LPCAT1/2, PHOSPHATIDYLCHOLINE

DIACYLGLYCEROL CHOLINEPHOSPHOTRANSFERASE (PDCT), FATTY ACID ELONASE 1 (FAE1) as well as FAD3.
Specifically, DPBF2 directly regulates the transcription of PDCT and FAE1 by binding to the promoter. This leads to

changes in the seed fatty acid composition. These results suggest that DPBF2 modulates the expression of genes
encoding fatty acid desaturase and acyl-editing enzymes and thereby modifies the unsaturated fatty acid
composition of seeds.