Revealing novel interactions between oak and Tubakia species: evidence of the efficacy of the sentinel arboreta strategy

In the present study, the sentinel arboreta strategy was applied, and its efficacy was evaluated at the Atatürk Arboretum (Istanbul, Turkey), having as a study case the interaction Tubakia spp.— Quercus spp. Thirty-four oak species native of America and Eurasia were sampled within the Fagaceae collection of the arboretum. Isolation trials were conducted from leaf necroses, and High Throughput Sequencing for fungal taxa was carried out from asymptomatic leaf blades. Four Tubakia species were identified, T. dryina , T. suttoniana , T. hallii, and T. macnabbii. Three out of four are of recent description and the present study contributed to updating their host-range. Thirty-two oak- Tubakia interactions new to science were described. Hypotheses were formulated on the possible movement across geographic areas of these species and on the risk posed in case of introduction in the distribution range of susceptible host species. As a conclusive remark, the present study confirmed the efficacy of the sentinel arboreta strategy to highlight new host–pathogen interactions and the risk of host-shift events.