Isoflavonoids are present in Arabidopsis thaliana despite the absence of any homologue to known isoflavonoid synthases

0082528 - ÚEB 2007 RIV FR eng J - Journal Article
Lapčík, O. - Honys, David - Koblovská, R. - Macková, Z. - Vítková, M. - Klejdus, B.
Isoflavonoids are present in Arabidopsis thaliana despite the absence of any homologue to known isoflavonoid synthases.
[Isoflavonoidy jsou přítomny v huseníčku thalově navzdory absenci blízkého homologu známých isoflkavonoid syntéz.]
Plant Physiology and Biochemistry. Roč. 44, 2-3 (2006), s. 106-114. ISSN 0981-9428
R&D Projects: GA ČR GA525/03/0352; GA AV ČR KJB6038409
Institutional research plan: CEZ:AV0Z50380511
Keywords : Arabidopsis thaliana * Brassicaceae * HPLC-MS
Subject RIV: EB - Genetics ; Molecular Biology
Impact factor: 1.847, year: 2006

Extracts from Arabidopsis thaliana leaves and inflorescence stalks and from Lepidium sativa (Brassicaceac) seedlings were analysed by HPLC-MS-SIM and by five isoflavonoid-specific ELISA methods after the HPLC fractionation of samples, in order to determine presence of isoflavonoids. Individual ELISAs were specific for daidzein, genistein, biochanin A and for their derivatives substituted either at the 4'- or at the 7-positions. Both analytical approaches revealed homologous spectra of isoflavonoids in both plant species. As the ononin specific immunoassay was not available this compound was only detected by HPLC-MS. Formononetin and prunetin represented the main aglycones followed by biochanin A, daidzein and genistein; sissotrin was the most abundant isoflavonoid glycoside followed by ononin, daidzin and genistin. The content of individual compounds ranged from a few micrograms up to 2.2 mg kg(-1) (dry weight). Expression profiles of A. thaliana genes homologous to enzymes involved in isoflavonoid synthesis and metabolism were extracted from publicly available transcriptomic datasets for various tissues. Genes likely to be involved in important steps of the isoflavonoid metabolism in A. thaliana were identified. However, in accord with the previously published data, no homologue to isoflavone synthases known from the Fabaceae plants was found. These aryl migrating enzymes belong to the CYP93C family that is absent in A. thaliana. We conclude that another gene must be responsible for biosynthesis of the isoflavone skeleton in Brassicaceae.

Extrakty z listů a stonků Arabidopsis thaliana a z klíčků Lepidium sativa byly analyzovány na přítomnost isoflavonoidů HPLC-MS-SIM a pěti specifickými ELISA metodami po frakcionaci HPLC. Jednotlivé ELISA metody jsou specifické pro dainzein, genistein, biochanin A a jejich deriváty. Nicméně ve srovnání s předchozími publikovanými daty nebyl v Arabidopsis thaliana nalezen žádný homolog isoflavonoidsyntázy. Je možná pravděpodobnost existence UFO.
Permanent Link: http://hdl.handle.net/11104/0146062