Final Report Summary - GENODED (Genomics data mining for the genetic analysis of populations of the Dutch elm disease (DED) fungi (Ophiostoma ulmi and O. novo-ulmi))
Project context and objectives
Two inter-fertile fungal species causing the Dutch elm disease (DED) (Ophiostoma ulmi and O. novo-ulmi) and two distinct subspecies of O. novo-ulmi, spp. novo-ulmi (European Access Network - EAN), and spp. americana (North American Network - NAN) coexist in elm stands in Europe, with interspecies and inter-subspecies hybrids. This constitutes an opportunity for a rapid emergence of new pathogenic races via inter-species/inter-subspecies gene flow.
Work performed
During the outgoing phase, in the partner organisation (Laval University, Canada), we developed new polymerase chain reaction (PCR)-based markers by mining Ophiostoma genomics data available at Dr Beniers' laboratory. We also used two main genetic resources:
- ESTs (expressed sequences tags);
- the sequence of the genome of the strain H327 of Ophiostoma novo-ulmi.
During the return phase, in the Technical University of Madrid (Spain) we used such neutral (microsatellite deoxyribonucleic acid - DNA) and non-neutral molecular makers (genes of pathogenicity) to estimate the genetic diversity and genetic structure with various indexes of diversity and fixation, and allele frequency in both Mallorca and the Iberian Peninsula. We studied the transposable elements present in the strain H327, and characterised one copy and gypsy element in detail. We also studied the polymorphism of the gypsy element in O. ulmi and in both subspecies of Ophiostoma novo-ulmi, and their phylogenetic relationships.
Main results
Our data suggests that the sexual reproduction might have played a major role in the genetic diversity of current populations, since current natural populations of Ophiostoma in the Iberian Peninsula have sexual reproduction spread by sexual spores.
The analyses provide an accurate idea of the levels of hybridisation and introgression, and the gene flow among populations. Our study provides new insights into the potential of transposable elements to generate genetic diversity by their activation. However, further studies will be necessary to discover the details of the evolutionary mechanisms that shape the populations of the DED fungi.
Two inter-fertile fungal species causing the Dutch elm disease (DED) (Ophiostoma ulmi and O. novo-ulmi) and two distinct subspecies of O. novo-ulmi, spp. novo-ulmi (European Access Network - EAN), and spp. americana (North American Network - NAN) coexist in elm stands in Europe, with interspecies and inter-subspecies hybrids. This constitutes an opportunity for a rapid emergence of new pathogenic races via inter-species/inter-subspecies gene flow.
Work performed
During the outgoing phase, in the partner organisation (Laval University, Canada), we developed new polymerase chain reaction (PCR)-based markers by mining Ophiostoma genomics data available at Dr Beniers' laboratory. We also used two main genetic resources:
- ESTs (expressed sequences tags);
- the sequence of the genome of the strain H327 of Ophiostoma novo-ulmi.
During the return phase, in the Technical University of Madrid (Spain) we used such neutral (microsatellite deoxyribonucleic acid - DNA) and non-neutral molecular makers (genes of pathogenicity) to estimate the genetic diversity and genetic structure with various indexes of diversity and fixation, and allele frequency in both Mallorca and the Iberian Peninsula. We studied the transposable elements present in the strain H327, and characterised one copy and gypsy element in detail. We also studied the polymorphism of the gypsy element in O. ulmi and in both subspecies of Ophiostoma novo-ulmi, and their phylogenetic relationships.
Main results
Our data suggests that the sexual reproduction might have played a major role in the genetic diversity of current populations, since current natural populations of Ophiostoma in the Iberian Peninsula have sexual reproduction spread by sexual spores.
The analyses provide an accurate idea of the levels of hybridisation and introgression, and the gene flow among populations. Our study provides new insights into the potential of transposable elements to generate genetic diversity by their activation. However, further studies will be necessary to discover the details of the evolutionary mechanisms that shape the populations of the DED fungi.