Title: Plant-symbiotic fungi as chemical engineers: multi-genome analysis of the Clavicipitaceae reveals dynamics of alkaloid loci
Authors: Schardl CL, Young CA, Hesse U, Jaromczyk JW, Farman ML, Tudzynski P, Roe BA, Amyotte SG, An Z, Andreeva K, Arnaoudova EG, Bullock CT, Calie P, Charlton ND, Chen L, Fleetwood DJ, Florea S, Guldener U, Harris DR, Haws DC, Jaromczyk J, Johnson RD, Khan AK, Liu J, Liu M, Machado C, Moore N, Nagabhyru P, Oeser B, Pan J, Panaccione DG, Schmid J, Schweri KK, Scott B, Sugawara K, Takach J, Voisey CR, Webb JS, Wiseman J, Zeng Z, Cox M, Dinkins RD, Glenn AE, Gordon A, Hollin W, Leistner E, Leuchtmann A, Li C, Mace W, O'Sullivan DM, Steiner U, Tanaka E, Wilson EV, Yoshida R
Journal: PLoS Genetics
Accepted date: 2012 Dec 31
Interpretive summary: The fungal family Clavicipitaceae includes plant symbionts and pathogens that produce neurotropic alkaloids with diverse effects on vertebrate and invertebrate animals. For example, ergot alkaloids are historically linked to mass poisonings (St. Anthony's fire) and sociological effects such as the Salem witch trials and the drug culture (LSD is an ergoline derivative). Ergot alkaloids in various forms also have medical uses ranging from treatment of Parkinsonism to aiding childbirth. Among the plant-associated Clavicipitaceae, Epichloë and Neotyphodium species deploy an especially wide variety of protective alkaloids within four major chemical classes: ergot alkaloids, indole-diterpenes, lolines, and peramine. Here we describe a comparative analysis of gene clusters for biosynthesis of alkaloids and other secondary metabolites among the Clavicipitaceae. We sequenced genomes of 12 Epichloë/Neotyphodium species, two related plant symbionts, and three Claviceps species, and compared their alkaloid biosynthetic gene clusters and alkaloid profiles. The alkaloid loci tended to have conserved cores with genes that specify skeleton structures, flanked by more variable genes for chemical modifications that yield the various forms within each alkaloid class. The alkaloid loci of the Epichloë and Neotyphodium species were riddled with very large arrays of retroelement-derived repeats. Such repeat arrays facilitate gene rearrangements, deletions, duplications, and neofunctionalizations, suggesting that these species are under selection for alkaloid diversification, perhaps due to their highly variable life histories and plant-protective roles.
Publication date: 2013 Feb 28