Manipulating a Single Transcription Factor, 1, Promotes Anthocyanin Accumulation in Barley Grains.

Barley has abundant anthocyanin-rich accessions, which renders it an ideal model to investigate the regulatory mechanism of anthocyanin biosynthesis. This study functionally characterized two transcription factors: Ant1 and Ant2. Sequence alignment showed that the coding sequences of 1 and 2 are conserved among 11 colored hulless barley and noncolored barley varieties. The expression profiles of 1 and 2 were divergent between species, and significantly higher expression was found in two colored Qingke accessions. The co-expression of 1 and 2 resulted in purple pigmentation in transient transformation systems via the promotion of the transcription of four structural genes. Ant1 interacted with Ant2, and overexpression of 1 activated the transcription of 2. Moreover, overexpression of 1 led to anthocyanin accumulation in the pericarp and aleurone layer of transgenic barley grains. Overall, our results suggest that anthocyanin-enriched barley grains can be produced by manipulating 1 expression.