| Title: | The cacao pathogen Moniliophthora roreri (Marasmiaceae) possesses biallelic A and B mating loci but reproduces clonally |
| Author(s): | Diaz-Valderrama JR; Aime MC; |
| Address: | "Department of Botany and Plant Pathology, Purdue University, West Lafayette, IN, USA" |
| ISSN/ISBN: | 1365-2540 (Electronic) 0018-067X (Print) 0018-067X (Linking) |
| Abstract: | "The cacao pathogen Moniliophthora roreri belongs to the mushroom-forming family Marasmiaceae, but it has never been observed to produce a fruiting body, which calls to question its capacity for sexual reproduction. In this study, we identified potential A (HD1 and HD2) and B (pheromone precursors and pheromone receptors) mating genes in M. roreri. A PCR-based method was subsequently devised to determine the mating type for a set of 47 isolates from across the geographic range of the fungus. We developed and generated an 11-marker microsatellite set and conducted association and linkage disequilibrium (standardized index of association, IA(s)) analyses. We also performed an ancestral reconstruction analysis to show that the ancestor of M. roreri is predicted to be heterothallic and tetrapolar, which together with sliding window analyses support that the A and B mating loci are likely unlinked and follow a tetrapolar organization within the genome. The A locus is composed of a pair of HD1 and HD2 genes, whereas the B locus consists of a paired pheromone precursor, Mr_Ph4, and receptor, STE3_Mr4. Two A and B alleles but only two mating types were identified. Association analyses divided isolates into two well-defined genetically distinct groups that correlate with their mating type; IA(s) values show high linkage disequilibrium as is expected in clonal reproduction. Interestingly, both mating types were found in South American isolates but only one mating type was found in Central American isolates, supporting a prior hypothesis of clonal dissemination throughout Central America after a single or very few introductions of the fungus from South America" |
| Keywords: | "Agaricales/*genetics/physiology Cacao/*microbiology Central America DNA, Fungal/genetics *Genes, Mating Type, Fungal Genetic Markers Linkage Disequilibrium Microsatellite Repeats Pheromones/genetics Phylogeny Receptors, Pheromone/genetics South America;" |
| Notes: | "MedlineDiaz-Valderrama, J R Aime, M C eng England 2016/03/05 Heredity (Edinb). 2016 Jun; 116(6):491-501. doi: 10.1038/hdy.2016.5. Epub 2016 Mar 2" |
