Abstract:
Anthocyanin, a kind of natural water-soluble pigment, determines fruit quality traits such as appearance and nutrition. Anthocyanin is synthesized by a series of enzymes located on the endoplasmic reticulum and subsequently transported to vacuole for storage. A considerable amount of information has been gathered on anthocyanin biosynthetic pathway and transcriptional regulation over the past decades. The key structural and regulatory genes participating in the pathway have been characterized in a variety of fruit species. However, the molecular mechanisms underlying transmembrane transport of anthocyanin after synthesis remain unclear. Here, we review current progress for anthocyanin transport, discuss three main transport models involving glutathione S-transferase, membrane transporters and vesicle trafficking. Despite the numerous proposed hypotheses, questions about the dynamic transport and aggregation of anthocyanin into vacuole still persist. Understanding the molecular mechanisms and regulatory networks of anthocyanin transport will not only contribute to expand our knowledge of anthocyanin metabolic pathway, but also provide the theoretical basis and molecular tools highly useful for improvement of fruit quality traits in breeding programs.