Cultivable Soil Fungi from Agricultural Farms in Tabuk, Northwestern Saudi Arabia: A Morphological and ITS-Based Survey

Documentation of cultivable soil fungi in the arid agricultural systems of the Arabian Peninsula remains limited. This study surveyed cultivable fungi in soils from four agricultural farms in the Tabuk region of northwestern Saudi Arabia, which differed in their recorded crops or vegetation (lemon, palm and grape at F1; olive, clover and pomegranate at F2; orange at F3; hot green pepper at F4). Composite soil samples were collected from three sampling zones per farm, and fungi were isolated by soil dilution plating on potato dextrose agar. Isolates were characterized by colony and microscopic morphology and by sequencing of the internal transcribed spacer (ITS) region of the ribosomal DNA. Twenty-three isolates were recovered: 22 were assigned to four genera (Aspergillus, 14 isolates; Fusarium, 4; Trichoderma, 3; Metarhizium, 1) and one could not be resolved. Because ITS alone does not reliably discriminate species in these genera, isolates are reported at genus level, and the species name of the closest GenBank ITS match is given only as an indication of affinity. Aspergillus was recovered from all four farms, Trichoderma from three and Metarhizium from one. Differences among farms are described without inference about their causes, because pesticide and fungicide histories, host-insect abundance and soil properties were not recorded, and insect pathogenicity was not tested. The study provides a baseline, culture-dependent, ITS-based record of cultivable fungi from Tabuk agricultural farms and a set of isolates for future multilocus identification.