Survey, Identification, and Characterization of Cylindrocarpon-Like Asexual Morphs in Spanish Forest Nurseries

Cylindrocarpon-like asexual morphs infect herbaceous and woody plants, mainly in agricultural scenarios, but also in forestry systems. The aim of the present study was to characterize a collection of Cylindrocarpon-like isolates recovered from the roots of a broad range of forest hosts from nurseries showing decline by morphological and molecular studies. Between 2009 and 2012, 17 forest nurseries in Spain were surveyed and a total of 103 Cylindrocarpon-like isolates were obtained. Isolates were identified based on DNA sequences of the partial gene regions histone H3 (his3). For the new species, the internal transcribed spacer and intervening 5.8S nrRNA gene (ITS) region, β-tubulin (tub2), and translation elongation factor 1-α (tef1) were also used to determine their phylogenetic position. Twelve species belonging to the genera Cylindrodendrum, Dactylonectria, and Ilyonectria were identified from damaged roots of 15 different host genera. The species C. alicantinum, D. macrodidyma, D. novozelandica, D. pauciseptata, D. pinicola, D. torresensis, I. capensis, I. cyclaminicola, I. liriodendri, I. pseudodestructans, I. robusta, and I. rufa were identified. In addition, two Dactylonectria species (D. hispanica sp. nov. and D. valentina sp. nov.), one Ilyonectria species (I. ilicicola sp. nov.), and one Neonectria species (N. quercicola sp. nov.) are newly described. The present study demonstrates the prevalence of this fungal group associated with seedlings of diverse hosts showing decline symptoms in forest nurseries in Spain.