Antagonistic activities of endophytic fungi isolated from pines against Diplodia sapinea (Fr.) Fuckel

Abstract

Diplodia sapinea, an endophytic fungus belonging to the Ascomycota, is commonly found on coniferous trees. While it typically exists as an endophyte, it can transform into an opportunistic pathogen under abiotic stress factors such as drought induced by climate change. The fungus enters the host through stomata on needles or via injured tissues, causing a disease known as Diplodia tip blight. This disease affects trees in various environments, including nurseries, plantation areas, natural forests, and urban trees. The prevalence of D. sapinea has significantly increased in Europe in recent years, and there is currently no established and effective control method worldwide. In response to this challenge, biological control method utilizing antagonist organisms have emerged as a promising alternative to combat Diplodia tip blight. The objective of this study is to evaluate the antagonistic activities of endophytic fungi isolated from different pine tree tissues against D. sapinea isolates obtained from Pinus halepensis and Pinus brutia under in vitro conditions. Identification of the isolates was carried out using both morphological and molecular methods. Fungal inhibition tests were conducted to assess the interaction between these isolates and D. sapinea isolates. The results of the tests revealed that 15 fungi, including Trichoderma sp. and Sydowia polyspora, demonstrated the potential to inhibit the growth of D. sapinea in vitro.