Browsing by Subject "Taxonomically restricted genes"

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    Lineage-specific gene radiations underlie the evolution of novel betalain pigmentation in Caryophyllales
    (Wiley, 2015-05-13) Brockington, Samuel F.; Yang, Ya; Gandía Herrero, Fernando; Covshoff, Sarah; Hibberd, Julián M.; Sage, Rowan F.; Wong, Gane K. S.; Moore, Michael J.; Smith, Stephen A.; Bioquímica y Biología Molecular "A"
    Betalain pigments are unique to the Caryophyllales and structurally and biosynthetically dis-tinct from anthocyanins. Two key enzymes within the betalain synthesis pathway have beenidentified: 4,5-dioxygenase (DODA) that catalyzes the formation of betalamic acid andCYP76AD1, a cytochrome P450 gene that catalyzes the formation of cyclo-DOPA. We performed phylogenetic analyses to reveal the evolutionary history of the DODA andCYP76AD1 lineages and in the context of an ancestral reconstruction of pigment states weexplored the evolution of these genes in relation to the complex evolution of pigments inCaryophylalles. Duplications within the CYP76AD1 and DODA lineages arose just before the origin of beta-lain pigmentation in the core Caryophyllales. The duplications gave rise to DODA-a andCYP76AD1-a isoforms that appear specific to betalain synthesis. Both betalain-specific isoformswere then lost or downregulated in the anthocyanic Molluginaceae and Caryophyllaceae. Our findings suggest a single origin of the betalain synthesis pathway, with neofunctionaliza-tion following gene duplications in the CYP76AD1 and DODA lineages. Loss of DODA-a andCYP76AD1-a in anthocyanic taxa suggests that betalain pigmentation has been lost twice inCaryophyllales, and exclusion of betalain pigments from anthocyanic taxa is mediated throughgene loss or downregulation. [Correction added after online publication 13 May 2015: in thelast two paragraphs of the Summary the gene name CYP761A was changed to CYP76AD1.]