Category:FL/Biosynthesis
Biosynthesis of Flavonoid
Flavonoid is synthesized through both the phenylpropanoid-acetate pathway and the acetate-malonate pathway in all higher plants (but not algae). Most plants contain the 6 major subgroups: chalcones, flavanones, flavones, flavonols, flavans, and anthocyani(di)ns. Aurones or isoflavonoids are not ubiquitous.
4-coumaroyl CoA + malonyl CoA | ||||||||||||||||
CHS | ||||||||||||||||
CHALCONES, AURONES |
chalconaringenin |
FLAVONES |
apigenin |
luteolin | ||||||||||||
CHI (isomerase) | FS (oxygenase) | |||||||||||||||
IFS |
naringenin FLAVANONE |
kaempferol |
FLAVONOLS |
quercetin |
myricetin | |||||||||||
ISO-FLAVONES |
F3H (hydroxylase) | FLS (oxygenase) | FLS | FLS | ||||||||||||
DIHYDRO FLAVONOLS |
dihydro-kaempferol |
F3'H +OH in B-ring |
dihydro-quercetin |
F3'5'H +OH in B-ring |
dihydro-myricetin | |||||||||||
DFR (reductase) | DFR | DFR | ||||||||||||||
flavan diol LEUCOANTHO-CYANIDINS |
leuco-pelargonidin |
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leuco-cyanidin |
LAR | leuco-delphinidin |
LAR | ||||||||||
LDOX (oxygenase) | PROANTHO- CYANIDINS * | LDOX | PROANTHO- CYANIDINS * | LDOX | *...polymers of flavanols | |||||||||||
ANTHO-CYANIDINS |
pelargonidin |
ANR | cyanidin |
ANR | delphinidin |
ANR | ||||||||||
UF3GT (+sugar) | epi-afzelechin |
UF3GT | epi-catechin |
UF3GT | epigallo-catechin |
FLAVAN 3-OLS | ||||||||||
ANTHO-CYANINS |
pelargonidin 3-glucoside |
cyanidin 3-glucoside |
delphinidin 3-glucoside | |||||||||||||
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Information for the Above Abbreviated Gene Names | |||
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Six Structural Genes | |||
Abbrev. | Name | Origin | Information |
CHS | chalcone synthase | Bacterial polyketide synthases, particularly those in fatty acid synthesis (Verwoert et al. 1992) | Early response against light [1] [2] |
CHI | chalcone-flavanone isomerase | Unclear and unique to plants.[3]
Eubacterium ramulus has the CHI activity. [4] |
Early response against light. |
F3H | flavanone 3-hydroxylase | 2-oxoglutarate-dependent dioxygenase family [5] | Early response in Arabidopsis but late in Antirrhinum [6] |
FLS | flavonol synthase | 2-oxoglutarate-dependent dioxygenase family [7] | Early response against light. In Arabidopsis, all structural genes are single-copy except for this one, to which six genes exist and two of them are not expressed. |
DFR | dihydroflavonol 4-reductase | NADPH-dependent reductase associated with steroid metabolism [8] | Later response |
ANS/LDOX | anthocyanidin synthase or leucoanthocyanidin dioxygenase | 2-oxoglutarate-dependent dioxygenase family | Later response |
Auxiliary Genes | |||
F3'H | flavonoid 3'-hydroxylase | cytochrome P450 hydroxylase family [9] | |
F3'5'H | flavonoid 3',5'-hydroxylase | cytochrome P450 hydroxylase family [10] | Not reported in mosses or liverworts. The transformation of the F3'5'H and the cytochrome b5 gene of petunia into carnation changed its flower color deep purple.[11][12] |
FSI | flavone synthase | Dioxygenase in parsley (FSI) and P450 monooxygenase in snapdragon (FSII). | |
LAR (or LCR) | leucoanthocyanidin reductase | ||
UF3GT | UDP flavonoid glucosyltransferase | ||
GST | glutathione-S-transferase | Transport of flavonoids from cytoplasm to vacuole or cell walls requires both GST and the glutathione pump in ATP-binding cassette family.[13][14] | |
AOMT | anthocyanin O-methyl transferase | ||
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Evolutionary Pressure
Rausher and colleagues studied the relationship between pathway architecture and protein evolutionary rates in anthocyanin biosynthetic pathways. Upstream enzymes showed reduced rates of non-synonymous substitution compared with downstream enzymes, which are under relaxed constraints, in both broad (Zea in monocot and Antirrhinum and Ipomoea in eudicot [1] [2] ) and narrow (within Ipomoea [3]) comparisons. Similarly, the downstream enzyme is under less selective pressure in the carotenoid biosynthetic pathway [4].
- ↑ Rausher MD, Miller R, Tiffin P (1999) "Patterns of evolutionary rate variation among genes of the anthocyanin biosynthetic pathway" Mol Biol Evol 16:266-274
- ↑ Lu Y, Rausher MD (2003) "Evolutionary rate variation in anthocyanin pathway genes" Mol Biol Evol 20:1844-1853
- ↑ Rausher MD, Lu Y, Meyer K (2008) "Variation in constraint versus positive selection as an explanation for evolutionary rate variation among anthocyanin genes" J Mol Evol 7:137-144
- ↑ Livingstone K, Anderson S (2009) "Patterns of variation in the evolution of carotenoid biosynthetic pathway enzymes of higher plants" J Heredity 100:754-761
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