Dutch elm disease is caused by the fungal pathogen Ophiostoma novo-ulmi which is transmitted by the native elm bark beetle, Hylurgopinus rufipes. We have found that four semiochemicals (the monoterpene (-)-beta-pinene and the sesquiterpenes (-)-alpha-cubebene, (+)-spiroaxa-5,7-diene and (+)-delta-cadinene) from diseased American elms, Ulmus americana, synergistically attract H. rufipes, and tha...

The health condition of the population of elms in the region of southern Bohemia was studied from the viewpoint of their decline, the occurrence of Dutch Elm Disease (DED) and the presence of other diseases. Of the total number of 105 elms in total 33 of them were without any symptoms of the disease or other damage. Elms regenerated quite spontaneously in the neighbourhood of mother trees and t...

The Ophiostoma piceae complex forms a monophyletic group of insect-dispersed pyrenomycetes with synnemata (Pesotum) and micronematous (Sporothrix) synanamorphs. Other species of Ophiostoma outside of the 0. piceae complex that form synnemata lack the Sporothrix state. The nine recognized species within the 0. piceae complex are delimited by synnema morphology, growth rate at 32 C, mating reacti...

The ascomycete fungus Ophiostoma novo-ulmi is responsible for the pandemic of Dutch elm disease that has been ravaging Europe and North America for 50 years. We proceeded to annotate the genome of the O. novo-ulmi strain H327 that was sequenced in 2012. The 31.784-Mb nuclear genome (50.1% GC) is organized into 8 chromosomes containing a total of 8,640 protein-coding genes that we validated with...

Fungal dimorphism is a complex trait and our understanding of the ability of fungi to display different growth morphologies is limited to a small number of model species. Here we study a highly aggressive dimorphic fungus, the ascomycete Ophiostoma novo-ulmi, which is a model in plant pathology and the causal agent of Dutch elm disease. The two growth phases that this fungus displays, i.e., a y...

Under the continuous pressure of Dutch elm disease (DED) in Europe, increasing genetic diversity Ulmus minor trees resistant to Ophiostoma novo-ulmi is a priority for species conservation and reintroduction. In this work we screened 121 U. genotypes resistance O. under field experimental conditions. The had been previously obtained through controlled crosses between two moderately (dams) one su...

Despite our increasing recognition of the key role that microbes play in ecosystem processes (e.g., Giller et al. 1997; Mills and Bever 1998; van der Heijden et al. 1998), concern over the loss of biodiversity in ecological communities rarely focuses on microbes— particularly pathogenic microbes which are more often targeted for eradication than preservation (but see Windsor 1995). Yet it is be...