AtMyb56 Regulates Anthocyanin Levels via the Modulation of Expression in Response to Sucrose in .

Sucrose is a crucial compound for the growth and development of plants, and the regulation of multiple genes depends on the amount of soluble sugars present. Sucrose acts as a signaling molecule that regulates a proton-sucrose symporter, with its sensor being the sucrose transporter. Flavonoid and anthocyanin biosynthesis are regulated by sucrose, and sucrose signaling can affect flavonoid and anthocyanin accumulation. In the present study, we found a Myb transcription factor affecting accumulation of anthocyanin. showed an increase in its expression in response to sucrose treatment. Under normal conditions, anthocyanin accumulation was similar between Col-0 (wild type) and mutant seedlings; however, under sucrose treatment, the level of anthocyanin accumulation was lower in the mutant plants than in Col-0 plants. Preliminary microarray analysis led to the investigation of the expression of one candidate gene, , in the mutant. The phosphate translocator, which is a plastidial phosphate antiporter family, catalyzes the import of glucose-6-phosphate (G-6-P) into the chloroplast. gene expression was altered in seedlings in a sucrosedependent manner in response to circadian cycle. Furthermore, the lack of resulted in altered accumulation of maltose in a sucrosedependent manner. Therefore, the sucrose responsive AtMyb56 regulates gene expression in a sucrose-dependent manner to modulate maltose and anthocyanin accumulations in response to the circadian cycle.