Botryosphaeriaceae species on forest trees in Portugal: diversity, distribution and pathogenicity

Abstract

Fungi in the family Botryosphaeriaceae are known as pathogens of diverse woody hosts, including forest tree species. Although, several of these fungi have been described in different forest hosts in Portugal, their diversity and distribution is still poorly understood. A survey was conducted across the country to identify Botryosphaeriaceae species associated with the main forest tree species in Portugal, Quercus suber, Eucalyptus globulus and Pinus pinaster. Additionally, a meta-analysis was performed to compile and organize all records known from Portugal. From this meta-analysis, 22 different Botryosphaeriaceae species were reported and 40 different plant hosts were recorded in several studies from agricultural crops to ornamental and forest species. A total of 105 host-pathogen interactions were identified. In the national survey, 12 Botryosphaeriaceae species were identified, with Diplodia corticola being the most frequent. Diplodia insularis, Diplodia pyri, Dothiorella plurivora and Dothiorella yunnana are reported for the first time in Portugal. Of the 23 different host-fungus associations identified, 10 are also recognised as new hosts. Artificial inoculation tests confirmed the pathogenicity of all species, except Dothiorella iberica, Dothiorella plurivora and Dothiorella yunnana, which are regarded as weakly or non-pathogenic to the hosts tested. Pathogenicity tests revealed the host-jump potential of some species, showing high susceptibility of Q. suber to Neofusicoccum parvum and N. eucalyptorum and of P. pinaster to D. corticola. Our results show that Botryosphaeriaceae species have a widespread distribution across the country, however some species such as D. corticola, D. sapinea and N. eucalyptorum exhibit a distribution that overlaps the distribution of their preferred hosts.