Uncovering the hidden leaf mycobiota of native juniper (Juniperus seravschanica) in Oman’s arid highlands

In this study, the fungal diversity associated with the leaves of Juniperus seravschanica in Jebel Al Sarah, the Western Hajar Mountains of Oman was investigated. A total of 206 fungal isolates were recovered from leaves using potato dextrose agar (PDA) media. All the isolates were subjected to sequencing of the internal transcribed spacer (ITS) region of the nuclear ribosomal DNA. Following a tailored quality check, 193 sequences were found to be of high quality and retained for subsequent analyses. These 193 samples represent 65 species from 38 genera and 23 families, identified through phylogenetic analyses of the ITS region. Among these 65 species, 35 species were reported as new recorded for Oman, raising the number of known fungi of the country to 461. Ascomycota was the dominant phylum, comprising 21 families, 35 genera, and 62 species. In contrast, Basidiomycota and Mucoromycota each was represented by a single family: Filobasidiaceae (Naganishia albidosimilis) and Mortierellaceae (Linnemannia camargensis and Mortierella alpina), respectively. Several species, including Dactylonectria, Fusarium, Neocosmospora, Neomicrosphaeropsis, Microsphaeropsis, Preussia, and Thyrostroma, are known pathogens in other plant species, but reported here for the first time from J. seravschanica. Interestingly, some fungal species with known biocontrol properties were also identified, including Clonostachys rosea, Leptobacillium chinense, and Naganishia albidosimilis, which have been reported as antagonists against plant-pathogenic fungi, nematodes, and bacteria, respectively. The identification of known plant pathogens highlights the potential biotic threats to juniper health, while the presence of biocontrol fungi suggests possible natural mechanisms of disease suppression.