title: Partial reconstruction of the ergot alkaloid pathway by heterologous gene expression in Aspergillus nidulans.
abstract: Ergot alkaloids are pharmaceutically and agriculturally important secondary metabolites produced by several species of fungi. Ergot alkaloid pathways vary among different fungal lineages, but the pathway intermediate chanoclavine-I is evolutionarily conserved among ergot alkaloid producers. At least four genes, dmaW, easF, easE, and easC, are necessary for pathway steps prior to chanoclavine-I; however, the sufficiency of these genes for chanoclavine-I synthesis has not been established. A fragment of genomic DNA containing dmaW, easF, easE, and easC was amplified from the human-pathogenic, ergot alkaloid-producing fungus Aspergillus fumigatus and transformed into  Aspergillus nidulans, a model fungus that does not contain any of the ergot alkaloid synthesis genes. HPLC and LC-MS analyses demonstrated that transformed A. nidulans strains produced chanoclavine-I and an earlier pathway intermediate. Aspergillus nidulans transformants containing dmaW, easF, and either easE or easC did not produce chanoclavine-I but did produce an early pathway intermediate and, in the case of the easC transformant, an additional ergot alkaloid-like compound. We conclude that dmaW, easF, easE, and easC are sufficient for the synthesis of chanoclavine-I in A. nidulans and expressing ergot alkaloid pathway genes in A. nidulans provides a novel approach to understanding the early steps in ergot alkaloid synthesis.
authors: Genetics and Developmental Biology Program, Division of Plant and Soil Sciences, West Virginia University, Morgantown, WV 26506, USA. kryan10@mix.wvu.edu
authors: Katy L
authors: KL
authors: Ryan
authors: Christopher T
authors: CT
authors: Moore
authors: Daniel G
authors: DG
authors: Panaccione
mesh_terms: D001232:Aspergillus fumigatus / Q000235:genetics; D001233:Aspergillus nidulans / Q000235:genetics* / Q000378:metabolism; D004876:Ergot Alkaloids / Q000235:genetics*; D015870:Gene Expression; D005800:Genes, Fungal / Q000235:genetics*; D009183:Mycotoxins / Q000235:genetics*
chemical_list: D004876:Ergot Alkaloids; D009183:Mycotoxins