Investigation and Identification of Fungi Associated with Juniper Tree Decline

In order to identify fungal agents associated with juniper trees in the highlands of Tarm County, samples of various tissues from affected trees were collected and subjected to cultivation and isolation using conventional methods. For species identification, both morphological and molecular methods were employed. To achieve this, DNA was extracted from 11 fungal species isolated. The internal transcribed spacer (ITS) region of their ribosomal DNA was amplified using universal primers (ITS-1 and ITS-4). Subsequently, their sequences were determined and compared to sequences available in databases to confirm the identification of species. In total, more than 150 fungal isolates were separated from diseased juniper trees over a span of three years. Based on morphological characteristics and ITS sequence analysis, the following fungal species were confirmed: Nigrospora oryzae (31 isolates), Penicillium spp. (9 isolates), Aspergillus spp. (4 isolates), Trichoderma spp. (5 isolates), Aureobasidium pullulans (33 isolates), Polyporus sp. (3 isolates), Phoma sp. (14 isolates), Phoma medicaginesis (3 isolates), Alternaria alternata (5 isolates), Alternaria sp. (9 isolates), Alternaria consortialis (6 isolates), Hormonema carpetanum (5 isolates), Hormonema sp. (9 isolates), Peyronellaea pinodella (4 isolates), Kabatiella microsticta (3 isolates), and Microsphaeropsis spp. (8 isolates). Most of these species are opportunistic pathogens, reported for the first time on juniper trees in Iran. These agents, in conjunction with host vulnerability due to infestations by phytophagous insects, drought stress, and pest attacks, accelerate the decline of the host trees.