Anthocyanins pathway

The riocus encodes the enzyme flavonoid 3 -hydroxylase (F3 H) [17, 18], and is an important controller of flux in the anthocyanin pathway in soybean seed coats (Fig. 4.1). F3 H diverts metabolic flux away from biosynthesis of orange (pelargoni-din) and blue (delphinidin) anthocyanins toward the red cyanidin-3-(9-glucoside, which is the main anthocyanin in the seed coats of black soybean [7, 8]. T increases the accumulation of delphidin-3-O-glucoside in black seed coats, even though it is not required for its biosynthesis [19]. Possible mechanisms for this include positive feedback, or the stabilization of the putative anthocyanin biosynthetic metabolon [20] by F3 Fl-derived membrane anchoring (Fig. 4.1). 

Regulation of anthocyanin production involves transcriptional activators of the R2R3 MYB and the basic helix-loop-helix (bHLH) (or MYC) types (Table 3.2). This was first revealed by studies of the monocot Z. mays. It was found that the anthocyanin pathway is turned on in this species through the combined action of one member of the COLORED ALEURONEl (C1)/PURPLE PLANT (PL) MYB family and one member of the REDl (R)/BOOSTERl (B) bHLH family. The members of the MYB and bHLH families are functionally redundant, and their specific expression patterns enable spatial and temporal control of anthocyanin biosynthesis. 

Boss, P.K., Davies, C., and Robinson, S.P., Analysis of the expression of anthocyanin pathway genes in developing Vitis vinifera L. cv. Shiraz grape berries and the implications for pathway regulation. Plant Physiol, 111, 1059, 1996. 

Carey, C.C. et al.. Mutations in the pale aleurone color 1 regulatory gene of the Zea mays anthocyanin pathway have distinct phenotypes relative to the functionally similar TRANSPARENT TESTA GLABRAl gene in Arabidopsis thaliana. Plant Cell, 16, 450, 2004. 

Chandler, V.R. et al.. Two regulatory genes of the maize anthocyanin pathway are homologous isolation of B using R genomic sequences. Plant Cell, 1, 1175, 1989. 

Christie, P.J., Alfenito, M.R., and Walbot, V., Impact of low-temperature stress on general phenylpropanoid and anthocyanin pathways enhancement of transcript abundance and anthocyanin pigmentation in maize seedlings, Planta, 194, 541, 1994. 

Radicella, J. P., Turks, D., and Chandler, V. L., 1991, Cloning and nucleotide sequence of a cDNA encoding B-Peru, a regulatory protein of the anthocyanin pathway in maize, Plant Mol. Biol. 17 127-130. 

Selinger D, Chandler V. 1999. A mutation in the pale aleurone color 1 gene identifies a novel regulator of the maize anthocyanin pathway. Plant Cell 11 5-14. 

TreuttCT D (2006) PH4 of petunia is an R2R3 MYB protein that activates vacuolar acidification through interactions with basic-hefix-loop-hefix transiaiption factors of the anthocyanin pathway. Environ Chtan Let 4 147... 

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