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Article: Identification of flavone phytoalexins and a pathogen-inducible flavone synthase II gene (SbFNSII) in sorghum

TitleIdentification of flavone phytoalexins and a pathogen-inducible flavone synthase II gene (SbFNSII) in sorghum
Authors
KeywordsColletotrichum sublineolum
CYP93G3
Flavone synthase II
Flavones
Sorghum
Issue Date2010
PublisherOxford University Press. The Journal's web site is located at http://jxb.oxfordjournals.org/
Citation
Journal Of Experimental Botany, 2010, v. 61 n. 4, p. 983-994 How to Cite?
AbstractFollowing inoculation with the anthracnose pathogen Colletotrichum sublineolum, seedlings of the sorghum resistant cultivar SC748-5 showed more rapid and elevated accumulation of luteolin than the susceptible cultivar BTx623. On the other hand, apigenin was the major flavone detected in infected BTx623 seedlings. Luteolin was demonstrated to show stronger inhibition of spore germination of C. sublineolum than apigenin. Because of their pathogen-inducible and antifungal nature, both flavone aglycones are considered sorghum phytoalexins. The key enzyme responsible for flavone biosynthesis has not been characterized in monocots. A sorghum pathogen-inducible gene encoding a cytochrome P450 protein (CYP93G3) in the uncharacterized CYP93G subfamily was identified. Transgenic expression of the P450 gene in Arabidopsis demonstrated that the encoded protein is a functional flavone synthase (FNS) II in planta. The sorghum gene was then termed SbFNSII. It is a single-copy gene located on chromosome 2 and the first FNSII gene characterized in a monocot. Metabolite analysis by liquid chromatography-tandem mass spectrometry (LC-MS/MS) in precursor ion scan mode revealed the accumulation of 2-hydroxynaringenin and 2-hydroxyeriodictyol hexosides in the transgenic Arabidopsis plants. Hence, SbFNSII appears to share a similar catalytic mechanism with the licorice and Medicago truncatula FNSIIs (CYP93B subfamily) by converting flavanones to flavone through the formation of 2-hydroxyflavanones.
Persistent Identifierhttp://hdl.handle.net/10722/69068
ISSN
2014 Impact Factor: 5.526
2014 SCImago Journal Rankings: 2.311
PubMed Central ID
ISI Accession Number ID
Funding AgencyGrant Number
Research Grants Council of the Hong Kong Special Administrative Region, ChinaHKU7527/06M
The University of Hong Kong Seed Funding200711159025
Funding Information:

This work was supported by the Research Grants Council of the Hong Kong Special Administrative Region, China (grant no. HKU7527/06M) and The University of Hong Kong Seed Funding program (project code 200711159025).

References

 

DC FieldValueLanguage
dc.contributor.authorDu, Yen_HK
dc.contributor.authorChu, Hen_HK
dc.contributor.authorWang, Men_HK
dc.contributor.authorChu, IKen_HK
dc.contributor.authorLo, Cen_HK
dc.date.accessioned2010-09-06T06:10:15Z-
dc.date.available2010-09-06T06:10:15Z-
dc.date.issued2010en_HK
dc.identifier.citationJournal Of Experimental Botany, 2010, v. 61 n. 4, p. 983-994en_HK
dc.identifier.issn0022-0957en_HK
dc.identifier.urihttp://hdl.handle.net/10722/69068-
dc.description.abstractFollowing inoculation with the anthracnose pathogen Colletotrichum sublineolum, seedlings of the sorghum resistant cultivar SC748-5 showed more rapid and elevated accumulation of luteolin than the susceptible cultivar BTx623. On the other hand, apigenin was the major flavone detected in infected BTx623 seedlings. Luteolin was demonstrated to show stronger inhibition of spore germination of C. sublineolum than apigenin. Because of their pathogen-inducible and antifungal nature, both flavone aglycones are considered sorghum phytoalexins. The key enzyme responsible for flavone biosynthesis has not been characterized in monocots. A sorghum pathogen-inducible gene encoding a cytochrome P450 protein (CYP93G3) in the uncharacterized CYP93G subfamily was identified. Transgenic expression of the P450 gene in Arabidopsis demonstrated that the encoded protein is a functional flavone synthase (FNS) II in planta. The sorghum gene was then termed SbFNSII. It is a single-copy gene located on chromosome 2 and the first FNSII gene characterized in a monocot. Metabolite analysis by liquid chromatography-tandem mass spectrometry (LC-MS/MS) in precursor ion scan mode revealed the accumulation of 2-hydroxynaringenin and 2-hydroxyeriodictyol hexosides in the transgenic Arabidopsis plants. Hence, SbFNSII appears to share a similar catalytic mechanism with the licorice and Medicago truncatula FNSIIs (CYP93B subfamily) by converting flavanones to flavone through the formation of 2-hydroxyflavanones.en_HK
dc.languageengen_HK
dc.publisherOxford University Press. The Journal's web site is located at http://jxb.oxfordjournals.org/en_HK
dc.relation.ispartofJournal of Experimental Botanyen_HK
dc.subjectColletotrichum sublineolumen_HK
dc.subjectCYP93G3en_HK
dc.subjectFlavone synthase IIen_HK
dc.subjectFlavonesen_HK
dc.subjectSorghumen_HK
dc.subject.meshCytochrome P-450 Enzyme System - chemistry - genetics - metabolism-
dc.subject.meshFlavones - biosynthesis-
dc.subject.meshPlant Proteins - chemistry - genetics - metabolism-
dc.subject.meshSorghum - enzymology - genetics - metabolism - microbiology-
dc.subject.meshTerpenes - metabolism-
dc.titleIdentification of flavone phytoalexins and a pathogen-inducible flavone synthase II gene (SbFNSII) in sorghumen_HK
dc.typeArticleen_HK
dc.identifier.openurlhttp://library.hku.hk:4550/resserv?sid=HKU:IR&issn=0022-0957&volume=61&issue=4&spage=983&epage=994&date=2010&atitle=Identification+of+flavone+phytoalexins+and+a+pathogen-inducible+flavone+synthase+II+gene+(SbFNSII)+in+sorghumen_HK
dc.identifier.emailWang, M: mfwang@hku.hken_HK
dc.identifier.emailChu, IK: ivankchu@hku.hken_HK
dc.identifier.emailLo, C: clivelo@hkucc.hku.hken_HK
dc.identifier.authorityWang, M=rp00800en_HK
dc.identifier.authorityChu, IK=rp00683en_HK
dc.identifier.authorityLo, C=rp00751en_HK
dc.description.naturepublished_or_final_version-
dc.identifier.doi10.1093/jxb/erp364en_HK
dc.identifier.pmid20007684-
dc.identifier.pmcidPMC2826645-
dc.identifier.scopuseid_2-s2.0-77649244513en_HK
dc.identifier.hkuros169748en_HK
dc.relation.referenceshttp://www.scopus.com/mlt/select.url?eid=2-s2.0-77649244513&selection=ref&src=s&origin=recordpageen_HK
dc.identifier.volume61en_HK
dc.identifier.issue4en_HK
dc.identifier.spage983en_HK
dc.identifier.epage994en_HK
dc.identifier.eissn1460-2431-
dc.identifier.isiWOS:000275567300005-
dc.publisher.placeUnited Kingdomen_HK
dc.identifier.scopusauthoridDu, Y=35725386400en_HK
dc.identifier.scopusauthoridChu, H=36870371300en_HK
dc.identifier.scopusauthoridWang, M=7406691844en_HK
dc.identifier.scopusauthoridChu, IK=7103327484en_HK
dc.identifier.scopusauthoridLo, C=15737175700en_HK

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