Abstract: Flower blotch is an important characteristic of flower ornamental traits. In previous
researches the components and biosynthetic pathway of the pigment of the flower blotch have been
understood well. This paper reviewed the recent research advance in the molecular mechanisms of flower
blotch formation. The anthocyanidin synthesis catalase genes and regulatory genes related in the flower
blotch were summarized，and the roles for the flower blotch formation of transposon，promoter，RNA
interference，methylation and virus were discussed. A schematic diagram of the molecular mechanisms of
flower blotch formation was calculated for a better understanding of the mechanisms，which would
promote the theory study for the breeding about flower blotch.

Key words: flower blotch, anthocyanidin synthesis catalase genes, MYB transcription factor, transposon, RNA interference