Ectopic Expression of the Grape Hyacinth ( Muscari armeniacum ) R2R3-MYB Transcription Factor Gene, MaAN2 , Induces Anthocyanin Accumulation in Tobacco

Anthocyanins are responsible for the different colors of ornamental plants. Grape hyacinth ( ), a monocot plant with bulbous flowers, is popular for its fascinating blue color. In the present study, we functionally characterized an R2R3-MYB transcription factor gene from . Our results indicated that participates in controlling anthocyanin biosynthesis. Sequence alignment and phylogenetic analysis suggested that MaAN2 belonged to the R2R3-MYB family AN2 subgroup. The anthocyanin accumulation of grape hyacinth flowers was positively correlated with the expression of . And the transcriptional expression of was also consistent with that of ( ) and ( ) in flowers. A dual luciferase transient expression assay indicated that when MaAN2 was co-inflitrated with TRANSPARENT TESTA8 (AtTT8), it strongly activated the promoters of and , but not the promoters of ( ), ( ), and ( ). Bimolecular fluorescence complementation assay confirmed that MaAN2 interacted with AtTT8 . The ectopic expression of in resulted in obvious red coloration of the leaves and much redder flowers. Almost all anthocyanin biosynthetic genes were remarkably upregulated in the leaves and flowers of the transgenic tobacco, and and (two basic helix-loop-helix anthocyanin regulatory genes) were highly expressed in the transformed leaves, compared to the empty vector transformants. Collectively, our results suggest that MaAN2 plays a role in anthocyanin biosynthesis.