title: Genetics, genomics and evolution of ergot alkaloid diversity.
abstract: The ergot alkaloid biosynthesis system has become an excellent model to study evolutionary diversification of specialized (secondary) metabolites. This is a very diverse class of alkaloids with various neurotropic activities, produced by fungi in several orders of the phylum Ascomycota, including plant pathogens and protective plant symbionts in the family Clavicipitaceae. Results of comparative genomics and phylogenomic analyses reveal multiple examples of three evolutionary processes that have generated ergot-alkaloid diversity: gene gains, gene losses, and gene sequence changes that have led to altered substrates or product specificities of the enzymes that they encode (neofunctionalization). The chromosome ends appear to be particularly effective engines for gene gains, losses and rearrangements, but not necessarily for neofunctionalization. Changes in gene expression could lead to accumulation of various pathway intermediates and affect levels of different ergot alkaloids. Genetic alterations associated with interspecific hybrids of Epichloë species suggest that such variation is also selectively favored. The huge structural diversity of ergot alkaloids probably represents adaptations to a wide variety of ecological situations by affecting the biological spectra and mechanisms of defense against herbivores, as evidenced by the diverse pharmacological effects of ergot alkaloids used in medicine.
authors: Forage Improvement Division, The Samuel Roberts Noble Foundation, Ardmore, OK 73401, USA. cayoung@noble.org.
authors: Carolyn A
authors: CA
authors: Young
authors: Department of Plant Pathology, University of Kentucky, Lexington, KY 40546, USA. schardl@uky.edu.
authors: Christopher L
authors: CL
authors: Schardl
authors: Division of Plant and Soil Sciences, West Virginia University, Morgantown, WV 26506, USA. danpan@wvu.edu.
authors: Daniel G
authors: DG
authors: Panaccione
authors: Department of Plant Pathology, University of Kentucky, Lexington, KY 40546, USA. sflor2@uky.edu.
authors: Simona
authors: S
authors: Florea
authors: Forage Improvement Division, The Samuel Roberts Noble Foundation, Ardmore, OK 73401, USA. jtakach@greenandgrow.com.
authors: Johanna E
authors: JE
authors: Takach
authors: Forage Improvement Division, The Samuel Roberts Noble Foundation, Ardmore, OK 73401, USA. ndcharlton@noble.org.
authors: Nikki D
authors: ND
authors: Charlton
authors: Computer Science Department, University of Kentucky, Lexington, KY 40546, USA. neil@uky.edu.
authors: Neil
authors: N
authors: Moore
authors: Advanced Genetic Technologies Center, University of Kentucky, Lexington, KY 40546, USA. jswebb2@uky.edu.
authors: Jennifer S
authors: JS
authors: Webb
authors: Advanced Genetic Technologies Center, University of Kentucky, Lexington, KY 40546, USA. jolanta.jaromczyk@uky.edu.
authors: Jolanta
authors: J
authors: Jaromczyk
mesh_terms: D004876:Ergot Alkaloids / Q000096:biosynthesis / Q000737:chemistry / Q000235:genetics*; D056426:Genetic Loci; D014644:Genetic Variation; D023281:Genomics; D006801:Humans; D010802:Phylogeny; D026801:Synteny
chemical_list: D004876:Ergot Alkaloids