title: De novo biosynthesis of cytokinins in the biotrophic fungus Claviceps purpurea.
abstract: Disease symptoms of some phytopathogenic fungi are associated with changes in cytokinin (CK) levels. Here, we show that the CK profile of ergot-infected rye plants is also altered, although no pronounced changes occur in the expression of the host plant's CK biosynthesis genes. Instead, we demonstrate a clearly different mechanism: we report on the first fungal de novo CK biosynthesis genes, prove their functions and constitute a biosynthetic pathway. The ergot fungus Claviceps purpurea produces substantial quantities of CKs in culture and, like plants, expresses enzymes containing the isopentenyltransferase and lonely guy domains necessary for de novo isopentenyladenine production. Uniquely, two of these domains are combined in one bifunctional enzyme, CpIPT-LOG, depicting a novel and potent mechanism for CK production. The fungus also forms trans-zeatin, a reaction catalysed by a CK-specific cytochrome P450 monooxygenase, which is encoded by cpp450 forming a small cluster with cpipt-log. Deletion of cpipt-log and cpp450 did not affect virulence of the fungus, but Δcpp450 mutants exhibit a hyper-sporulating phenotype, implying that CKs are environmental factors influencing fungal development.
authors.affiliation: Institute of Plant Biology and Biotechnology, Westfälische Wilhelms-University Münster, Schlossplatz 8, 48143, Münster, Germany.
authors.forename: Janine
authors.initials: J
authors.lastname: Hinsch
authors.affiliation: Centre of the Region Haná for Biotechnological and Agricultural Research, Palacký University & Institute of Experimental Botany AS CR, Šlechtitelů 11, 78371, Olomouc, Czech Republic.
authors.forename: Josef
authors.initials: J
authors.lastname: Vrabka
authors.affiliation: Institute of Plant Biology and Biotechnology, Westfälische Wilhelms-University Münster, Schlossplatz 8, 48143, Münster, Germany.
authors.forename: Birgitt
authors.initials: B
authors.lastname: Oeser
authors.affiliation: Centre of the Region Haná for Biotechnological and Agricultural Research, Palacký University & Institute of Experimental Botany AS CR, Šlechtitelů 11, 78371, Olomouc, Czech Republic.
authors.forename: Ondřej
authors.initials: O
authors.lastname: Novák
authors.affiliation: Centre of the Region Haná for Biotechnological and Agricultural Research, Palacký University & Institute of Experimental Botany AS CR, Šlechtitelů 11, 78371, Olomouc, Czech Republic.
authors.forename: Petr
authors.initials: P
authors.lastname: Galuszka
authors.affiliation: Institute of Plant Biology and Biotechnology, Westfälische Wilhelms-University Münster, Schlossplatz 8, 48143, Münster, Germany.
authors.forename: Paul
authors.initials: P
authors.lastname: Tudzynski
mesh_terms: D019883:Alkyl and Aryl Transferases / Q000378:metabolism; D002967:Claviceps / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*; D003577:Cytochrome P-450 Enzyme System / Q000235:genetics; D003583:Cytokinins / Q000096:biosynthesis*; D017353:Gene Deletion; D005800:Genes, Fungal / Q000235:genetics; D017343:Genes, Plant / Q000235:genetics; D007541:Isopentenyladenosine / Q000096:biosynthesis; D012434:Secale / Q000382:microbiology*
chemical_list: D003583:Cytokinins; C001478:N(6)-(delta(2)-isopentenyl)adenine; D007541:Isopentenyladenosine; D003577:Cytochrome P-450 Enzyme System; D019883:Alkyl and Aryl Transferases; C024274:adenylate isopentenyltransferase