title: Biosynthesis and genetic regulation of proanthocyanidins in plants.
abstract: Proanthocyanidins (PAs), also known as condensed tannins, are a group of polyphenolic secondary metabolites synthesized in plants as oligomers or polymers of flavan-3-ol units via the flavonoid pathway. Due to their structural complexity and varied composition, only in the recent years has the study on the biosynthesis and regulation of PAs in plants taken off, although some details of the synthetic mechanism remain unclear. This paper aims to summarize the status of research on the structures of PAs in plants, the genes encoding key enzymes of biosynthetic pathway, the transport factors, the transcriptional regulation of PA biosynthesis and the genetic manipulation of PAs. The problems of this field were also discussed, including the nature of the final "enzyme" which catalyzes the polymerization reaction of PAs and the possible mechanism of how the elementary units of flavanols are assembled in vivo.
authors.affiliation: Center for Viticulture and Enology, College of Food Science & Nutritional Engineering, China Agricultural University, Beijing, PR China. wheyfey@yahoo.com.cn
authors.forename: Fei
authors.initials: F
authors.lastname: He
authors.forename: Qiu-Hong
authors.initials: QH
authors.lastname: Pan
authors.forename: Ying
authors.initials: Y
authors.lastname: Shi
authors.forename: Chang-Qing
authors.initials: CQ
authors.lastname: Duan
mesh_terms: D053898:Biosynthetic Pathways; D005419:Flavonoids / Q000096:biosynthesis / Q000737:chemistry; D018506:Gene Expression Regulation, Plant; D008954:Models, Biological; D015394:Molecular Structure; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism; D010944:Plants / Q000235:genetics* / Q000378:metabolism*; D044945:Proanthocyanidins / Q000096:biosynthesis* / Q000737:chemistry
chemical_list: D005419:Flavonoids; D010940:Plant Proteins; D044945:Proanthocyanidins