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Molecular Cloning and Functional Characterization of a Novel (Iso)flavone 4',7-O-diglucoside Glucosyltransferase from Pueraria lobata.

Wang X, Fan R, Li J, Li C, Zhang Y - Front Plant Sci (2016)

Bottom Line: Pueraria lobata roots accumulate a rich source of isoflavonoid glycosides, including 7-O- and 4'-O-mono-glucosides, and 4',7-O-diglucosides, which have numerous human health benefits.Real-time PCR analysis showed that PlUGT2 is preferentially transcribed in roots relative to other organs of P. lobata, which is coincident with the accumulation pattern of 4'-O-glucosides and 4',7-O-diglucosides in P. lobata.The identification of PlUGT2 would help to decipher the P. lobata isoflavonoid glucosylations in vivo and may provide a useful enzyme catalyst for an efficient biotransformation of isoflavones or other natural products for food or pharmacological purposes.

View Article: PubMed Central - PubMed

Affiliation: CAS Key Laboratory of Plant Germplasm Enhancement and Specialty Agriculture, Wuhan Botanical Garden, Chinese Academy of Sciences Wuhan, China.

ABSTRACT
Pueraria lobata roots accumulate a rich source of isoflavonoid glycosides, including 7-O- and 4'-O-mono-glucosides, and 4',7-O-diglucosides, which have numerous human health benefits. Although, isoflavonoid 7-O-glucosyltranferases (7-O-UGTs) have been well-characterized at molecular levels in legume plants, genes, or enzymes that are required for isoflavonoid 4'-O- and 4',7-O-glucosylation have not been identified in P. lobata to date. Especially for the 4',7-O-di-glucosylations, the genetic control for this tailing process has never been elucidated from any plant species. Through transcriptome mining, we describe here the identification and characterization of a novel UGT (designated PlUGT2) governing the isoflavonoid 4',7-O-di-glucosylations in P. lobata. Biochemical roles of PlUGT2 were assessed by in vitro assays with PlUGT2 protein produced in Escherichia coli and analyzed for its qualitative substrate specificity. PlUGT2 was active with various (iso)flavonoid acceptors, catalyzing consecutive glucosylation activities at their O-4' and O-7 positions. PlUGT2 was most active with genistein, a general isoflavone in legume plants. Real-time PCR analysis showed that PlUGT2 is preferentially transcribed in roots relative to other organs of P. lobata, which is coincident with the accumulation pattern of 4'-O-glucosides and 4',7-O-diglucosides in P. lobata. The identification of PlUGT2 would help to decipher the P. lobata isoflavonoid glucosylations in vivo and may provide a useful enzyme catalyst for an efficient biotransformation of isoflavones or other natural products for food or pharmacological purposes.

No MeSH data available.


Related in: MedlinePlus

Concentrations of isoflavone glucosides biosynthesized in different organs of P. lobata.
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Figure 2: Concentrations of isoflavone glucosides biosynthesized in different organs of P. lobata.

Mentions: Isoflavonoid glucosides in P. lobata were analyzed by LC–MS analysis (Figure 2). The identity of these compounds was determined based on their HPLC retention times and individual mass spectrums in comparisons with corresponding authentic standards. The isoflavone glucosides detected here can be classified into four groups based on their glucosyl positions: 7-O-glucosides (daidzin, genistin, and ononin), 4′-O-glucosides (daidzein 4′-O-glucoside, genistein 4′-O-glucoside), 4′,7-O-diglucoside (daidzein 4′,7-O-diglucoside), and 8-C-glucosides (daidzein 8-C-glucoside, puerarin). For all these glucosides, roots are their main accumulation sites in P. lobata, especially, ononin and daidzein 4′-O-diglucoside were only found in the roots but not in the leaves and stems. Among these glucosides within P. lobata roots, 7-O-glucosides (daidzin and genistin) and 8-C-glucoside (puerarin) are predominant (daidzin, 1.72 ± 0.13 mg/g; genistin, 4.09 ± 0.78 mg/g; puerarin, 5.47 ± 0.29 mg/g) while 4′-O-glucosides and 4′,7-O-diglucoside accumulate at much lower amounts (Figure 2).


Molecular Cloning and Functional Characterization of a Novel (Iso)flavone 4',7-O-diglucoside Glucosyltransferase from Pueraria lobata.

Wang X, Fan R, Li J, Li C, Zhang Y - Front Plant Sci (2016)

Concentrations of isoflavone glucosides biosynthesized in different organs of P. lobata.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4814453&req=5

Figure 2: Concentrations of isoflavone glucosides biosynthesized in different organs of P. lobata.
Mentions: Isoflavonoid glucosides in P. lobata were analyzed by LC–MS analysis (Figure 2). The identity of these compounds was determined based on their HPLC retention times and individual mass spectrums in comparisons with corresponding authentic standards. The isoflavone glucosides detected here can be classified into four groups based on their glucosyl positions: 7-O-glucosides (daidzin, genistin, and ononin), 4′-O-glucosides (daidzein 4′-O-glucoside, genistein 4′-O-glucoside), 4′,7-O-diglucoside (daidzein 4′,7-O-diglucoside), and 8-C-glucosides (daidzein 8-C-glucoside, puerarin). For all these glucosides, roots are their main accumulation sites in P. lobata, especially, ononin and daidzein 4′-O-diglucoside were only found in the roots but not in the leaves and stems. Among these glucosides within P. lobata roots, 7-O-glucosides (daidzin and genistin) and 8-C-glucoside (puerarin) are predominant (daidzin, 1.72 ± 0.13 mg/g; genistin, 4.09 ± 0.78 mg/g; puerarin, 5.47 ± 0.29 mg/g) while 4′-O-glucosides and 4′,7-O-diglucoside accumulate at much lower amounts (Figure 2).

Bottom Line: Pueraria lobata roots accumulate a rich source of isoflavonoid glycosides, including 7-O- and 4'-O-mono-glucosides, and 4',7-O-diglucosides, which have numerous human health benefits.Real-time PCR analysis showed that PlUGT2 is preferentially transcribed in roots relative to other organs of P. lobata, which is coincident with the accumulation pattern of 4'-O-glucosides and 4',7-O-diglucosides in P. lobata.The identification of PlUGT2 would help to decipher the P. lobata isoflavonoid glucosylations in vivo and may provide a useful enzyme catalyst for an efficient biotransformation of isoflavones or other natural products for food or pharmacological purposes.

View Article: PubMed Central - PubMed

Affiliation: CAS Key Laboratory of Plant Germplasm Enhancement and Specialty Agriculture, Wuhan Botanical Garden, Chinese Academy of Sciences Wuhan, China.

ABSTRACT
Pueraria lobata roots accumulate a rich source of isoflavonoid glycosides, including 7-O- and 4'-O-mono-glucosides, and 4',7-O-diglucosides, which have numerous human health benefits. Although, isoflavonoid 7-O-glucosyltranferases (7-O-UGTs) have been well-characterized at molecular levels in legume plants, genes, or enzymes that are required for isoflavonoid 4'-O- and 4',7-O-glucosylation have not been identified in P. lobata to date. Especially for the 4',7-O-di-glucosylations, the genetic control for this tailing process has never been elucidated from any plant species. Through transcriptome mining, we describe here the identification and characterization of a novel UGT (designated PlUGT2) governing the isoflavonoid 4',7-O-di-glucosylations in P. lobata. Biochemical roles of PlUGT2 were assessed by in vitro assays with PlUGT2 protein produced in Escherichia coli and analyzed for its qualitative substrate specificity. PlUGT2 was active with various (iso)flavonoid acceptors, catalyzing consecutive glucosylation activities at their O-4' and O-7 positions. PlUGT2 was most active with genistein, a general isoflavone in legume plants. Real-time PCR analysis showed that PlUGT2 is preferentially transcribed in roots relative to other organs of P. lobata, which is coincident with the accumulation pattern of 4'-O-glucosides and 4',7-O-diglucosides in P. lobata. The identification of PlUGT2 would help to decipher the P. lobata isoflavonoid glucosylations in vivo and may provide a useful enzyme catalyst for an efficient biotransformation of isoflavones or other natural products for food or pharmacological purposes.

No MeSH data available.


Related in: MedlinePlus