Botryosphaeriaceae from Eucalyptus and Native Myrtaceae in Uruguay

Resumo

Species of the Botryosphaeriaceae are important pathogens causing cankers and die-back on many woody plants. In Uruguay, Neofusicoccum eucalyptorum (=Botryosphaeria eucalyptorum), N. ribis (=B. ribis) and B. dothidea have previously been associated with stem cankers on plantation grown Eucalyptus globulus. These fungi also exist as endophytes in healthy Eucalyptus leaves, twigs and stems, typically causing disease after the onset of stress. There is good evidence to suggest that species of the Botryosphaeriaceae, other than those previously reported, could cause cankers on Eucalyptus spp. and native Myrtaceae trees in Uruguay. In this study, we identified the Botryosphaeriaceae present on Eucalyptus spp. and on native Myrtaceae trees, and considered the genetic diversity between isolates found on both groups of hosts. Symptomatic and asymptomatic material was collected countrywide from Eucalyptus spp. and native Myrtaceae. Monosporic cultures were identified based on conidial morphology and comparisons of DNA sequences for the ITS region of the rDNA operon. Results revealed that isolates of the N. parvum-N. ribis complex, and B. dothidea were present on both Eucalyptus spp. and native Myrtaceae. In contrast, N. eucalyptorum was found only on Eucalyptus spp. and Diplodia seriata-related (=B. obtusa) isolates were obtained only from native trees. This study expands the knowledge of the occurrence of Botryosphaeriaceae on native and introduced Myrtaceae in Uruguay.