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dc.contributor.authorBruno, Mark
dc.contributor.authorAl-Babili, Salim
dc.date.accessioned2016-11-03T08:29:19Z
dc.date.available2016-11-03T08:29:19Z
dc.date.issued2016-03-05
dc.identifier.citationBruno M, Al-Babili S (2016) On the substrate specificity of the rice strigolactone biosynthesis enzyme DWARF27. Planta 243: 1429–1440. Available: http://dx.doi.org/10.1007/s00425-016-2487-5.
dc.identifier.issn0032-0935
dc.identifier.issn1432-2048
dc.identifier.pmid26945857
dc.identifier.doi10.1007/s00425-016-2487-5
dc.identifier.urihttp://hdl.handle.net/10754/621438
dc.description.abstractMain conclusion: The β-carotene isomerase OsDWARF27 is stereo- and double bond-specific. It converts bicyclic carotenoids with at least one unsubstituted β-ionone ring. OsDWARF27 may contribute to the formation of α-carotene-based strigolactone-like compounds.Strigolactones (SLs) are synthesized from all-trans-β-carotene via a pathway involving the β-carotene isomerase DWARF27, the carotenoid cleavage dioxygenases 7 and 8 (CCD7, CCD8), and cytochrome P450 enzymes from the 711 clade (MAX1 in Arabidopsis). The rice enzyme DWARF27 was shown to catalyze the reversible isomerization of all-trans- into 9-cis-β-carotene in vitro. β-carotene occurs in different cis-isomeric forms, and plants accumulate other carotenoids, which may be substrates of DWARF27. Here, we investigated the stereo and substrate specificity of the rice enzyme DWARF27 in carotenoid-accumulating E. coli strains and in in vitro assays performed with heterologously expressed and purified enzyme. Our results suggest that OsDWARF27 is strictly double bond-specific, solely targeting the C9–C10 double bond. OsDWARF27 did not introduce a 9-cis-double bond in 13-cis- or 15-cis-β-carotene. Substrates isomerized by OsDWARF27 are bicyclic carotenoids, including β-, α-carotene and β,β-cryptoxanthin, that contain at least one unsubstituted β-ionone ring. Accordingly, OsDWARF27 did not produce the abscisic acid precursors 9-cis-violaxanthin or -neoxanthin from the corresponding all-trans-isomers, excluding a direct role in the formation of this carotenoid derived hormone. The conversion of all-trans-α-carotene yielded two different isomers, including 9′-cis-α-carotene that might be the precursor of strigolactones with an ε-ionone ring, such as the recently identified heliolactone. © 2016 Springer-Verlag Berlin Heidelberg
dc.description.sponsorshipWe thank Dr. Peter Beyer, University of Freiburg, Germany, for valuable discussions and Dr. Hansgeorg Ernst, BASF, Germany, for providing the synthetic apocarotenoid substrates. The research reported in this publication was supported by funding from King Abdullah University of Science and Technology (KAUST) and the EU (METAPRO; FP7 KBBE-2009-3-1-01).
dc.publisherSpringer Nature
dc.subjectApocarotenoids
dc.subjectCarlactone
dc.subjectCarotene isomerase
dc.subjectCarotenoid cleavage dioxygenase
dc.subjectCarotenoids
dc.subjectStrigolactones
dc.titleOn the substrate specificity of the rice strigolactone biosynthesis enzyme DWARF27
dc.typeArticle
dc.contributor.departmentBiological and Environmental Sciences and Engineering (BESE) Division
dc.contributor.departmentDesert Agriculture Initiative
dc.contributor.departmentPlant Science
dc.identifier.journalPlanta
dc.contributor.institutionFaculty of Biology, Albert-Ludwigs University of Freiburg, Schaenzlestr. 1, Freiburg, Germany
kaust.personAl-Babili, Salim
dc.date.published-online2016-03-05
dc.date.published-print2016-06


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