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Article: CYP93G2 is a flavanone 2-Hydroxylase required for C-Glycosylflavone biosynthesis in rice

TitleCYP93G2 is a flavanone 2-Hydroxylase required for C-Glycosylflavone biosynthesis in rice
Authors
KeywordsBiology
Botany
Issue Date2010
PublisherAmerican Society of Plant Biologists. The Journal's web site is located at http://www.plantphysiol.org
Citation
Plant Physiology, 2010, v. 154 n. 1, p. 324-333 How to Cite?
AbstractC-Glycosylflavones are ubiquitous in the plant kingdom, and many of them have beneficial effects on human health. They are a special group of flavonoid glycosides in which the sugars are C-linked to the flavone skeleton. It has been long presumed that C-glycosylflavones have a different biosynthetic origin from O-glycosylflavonoids. In rice (Oryza sativa), a C-glucosyltransferase (OsCGT) that accepts 2-hydroxyflavanone substrates and a dehydratase activity that selectively converts C-glucosyl-2- hydroxyflavanones to 6C-glucosylflavones were recently described. In this study, we provide in vitro and in planta evidence that the rice P450 CYP93G2 protein encoded by Os06g01250 is a functional flavanone 2-hydroxylase. CYP93G2 is related to the CYP93B subfamily, which consists of dicot flavone synthase II enzymes. In the presence of NADPH, recombinant CYP93G2 converts naringenin and eriodictyol to the corresponding 2-hydroxyflavanones. In addition, CYP93G2 generates 2-hydroxyflavanones, which are modified by O-glycosylation in transgenic Arabidopsis (Arabidopsis thaliana). Coexpression of CYP93G2 and OsCGT in Arabidopsis resulted in the production of C-glucosyl-2-hydroxyflavanones in the dibenzoylmethane tautomeric form. The same structure was reported previously for the in vitro OsCGT reaction products. Thus, CYP93G2 generates 2-hydroxyflavanone substrates from flavanones for C-glucosylation by OsCGT in planta. Furthermore, knocking down Os06g01250 in rice (O. sativa subsp. japonica 'Zhonghua 11') preferentially depleted the accumulation of C-glycosylapigenin, C-glycosylluteolin, and C-glycosylchrysoeriol but did not affect the levels of tricin, which is frequently present as O-glycosides in cereals. Taken together, our work conclusively assigned CYP93G2 as the first enzyme that channels flavanones to C-glycosylflavone biosynthesis in rice. © 2010 American Society of Plant Biologists.
Persistent Identifierhttp://hdl.handle.net/10722/123927
ISSN
2015 Impact Factor: 6.28
2015 SCImago Journal Rankings: 3.642
PubMed Central ID
ISI Accession Number ID
Funding AgencyGrant Number
Council of the Hong Kong Special Administrative Region, ChinaHKU7527/06M
HKU3/07C
Funding Information:

This work was supported by the Research Grants Council of the Hong Kong Special Administrative Region, China (grant nos. HKU7527/06M and HKU3/07C).

References

 

DC FieldValueLanguage
dc.contributor.authorDu, Yen_HK
dc.contributor.authorChu, Hen_HK
dc.contributor.authorChu, IKen_HK
dc.contributor.authorLo, Cen_HK
dc.date.accessioned2010-10-08T03:45:16Z-
dc.date.available2010-10-08T03:45:16Z-
dc.date.issued2010en_HK
dc.identifier.citationPlant Physiology, 2010, v. 154 n. 1, p. 324-333en_HK
dc.identifier.issn0032-0889en_HK
dc.identifier.urihttp://hdl.handle.net/10722/123927-
dc.description.abstractC-Glycosylflavones are ubiquitous in the plant kingdom, and many of them have beneficial effects on human health. They are a special group of flavonoid glycosides in which the sugars are C-linked to the flavone skeleton. It has been long presumed that C-glycosylflavones have a different biosynthetic origin from O-glycosylflavonoids. In rice (Oryza sativa), a C-glucosyltransferase (OsCGT) that accepts 2-hydroxyflavanone substrates and a dehydratase activity that selectively converts C-glucosyl-2- hydroxyflavanones to 6C-glucosylflavones were recently described. In this study, we provide in vitro and in planta evidence that the rice P450 CYP93G2 protein encoded by Os06g01250 is a functional flavanone 2-hydroxylase. CYP93G2 is related to the CYP93B subfamily, which consists of dicot flavone synthase II enzymes. In the presence of NADPH, recombinant CYP93G2 converts naringenin and eriodictyol to the corresponding 2-hydroxyflavanones. In addition, CYP93G2 generates 2-hydroxyflavanones, which are modified by O-glycosylation in transgenic Arabidopsis (Arabidopsis thaliana). Coexpression of CYP93G2 and OsCGT in Arabidopsis resulted in the production of C-glucosyl-2-hydroxyflavanones in the dibenzoylmethane tautomeric form. The same structure was reported previously for the in vitro OsCGT reaction products. Thus, CYP93G2 generates 2-hydroxyflavanone substrates from flavanones for C-glucosylation by OsCGT in planta. Furthermore, knocking down Os06g01250 in rice (O. sativa subsp. japonica 'Zhonghua 11') preferentially depleted the accumulation of C-glycosylapigenin, C-glycosylluteolin, and C-glycosylchrysoeriol but did not affect the levels of tricin, which is frequently present as O-glycosides in cereals. Taken together, our work conclusively assigned CYP93G2 as the first enzyme that channels flavanones to C-glycosylflavone biosynthesis in rice. © 2010 American Society of Plant Biologists.en_HK
dc.languageeng-
dc.publisherAmerican Society of Plant Biologists. The Journal's web site is located at http://www.plantphysiol.orgen_HK
dc.relation.ispartofPlant Physiologyen_HK
dc.rightsFOR PREPRINT: 'The title of the web preprint that it is under review (or accepted for publication) by The Plant Cell.'-
dc.subjectBiology-
dc.subjectBotany-
dc.titleCYP93G2 is a flavanone 2-Hydroxylase required for C-Glycosylflavone biosynthesis in riceen_HK
dc.typeArticleen_HK
dc.identifier.openurlhttp://library.hku.hk:4550/resserv?sid=HKU:IR&issn=0032-0889&volume=154&issue=1&spage=324&epage=333&date=2010&atitle=CYP93G2+is+a+flavanone+2-hydroxylase+required+for+C-glycosyl-flavone+biosynthesis+in+rice-
dc.identifier.emailChu, IK: ivankchu@hku.hken_HK
dc.identifier.emailLo, C: clivelo@hkucc.hku.hken_HK
dc.identifier.authorityChu, IK=rp00683en_HK
dc.identifier.authorityLo, C=rp00751en_HK
dc.description.naturelink_to_OA_fulltext-
dc.identifier.doi10.1104/pp.110.161042en_HK
dc.identifier.pmid20647377-
dc.identifier.pmcidPMC2938165-
dc.identifier.scopuseid_2-s2.0-77956695438en_HK
dc.identifier.hkuros173532-
dc.relation.referenceshttp://www.scopus.com/mlt/select.url?eid=2-s2.0-77956695438&selection=ref&src=s&origin=recordpageen_HK
dc.identifier.volume154en_HK
dc.identifier.issue1en_HK
dc.identifier.spage324en_HK
dc.identifier.epage333en_HK
dc.identifier.eissn1532-2548-
dc.identifier.isiWOS:000281570000026-
dc.publisher.placeUnited Statesen_HK
dc.identifier.scopusauthoridDu, Y=35725386400en_HK
dc.identifier.scopusauthoridChu, H=36870371300en_HK
dc.identifier.scopusauthoridChu, IK=7103327484en_HK
dc.identifier.scopusauthoridLo, C=15737175700en_HK

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