Morphological and Molecular Characterization of Two Isolates of Leveillula taurica Causing Powdery Mildew on Protected Tomatoes in Tartous Coastal Region, Syria

Alio, N., S. Al-Maghribi and N. Mualla. 2024. Morphological and Molecular Characterization of Two Isolates of Leveillula taurica Causing Powdery Mildew on Protected Tomatoes in Tartous Coastal Region, Syria. Arab Journal of Plant Protection, 42(4): 436-442. https://doi.org/10.22268/AJPP-001275 Two isolates were characterized as Leveillula taurica based on morphological features and sequencing of ITS regions. The typical symptoms appeared on Mandalon cultivar as bright yellow spots on the upper side of the leaves, and whitish powdery sporulation on the corresponding lower surface, with no cleistothecia formation. Light and electron microscopy showed a lanceolate primary and cylindrical secondary conidia on pseudoidium conidiphores, and other morphological features were similar to those of L. taurica. The ribosomal DNA internal transcribed spacer (ITS) sequence confirmed the morphological characterization. The results of sequence homology for the two isolates using BLAST showed similarity to L. taurica species, with a query coverage reached 100% and more than 99% identity with many isolates registered in the GenBank which infect tomato and other hosts. To the best of our knowledge, this is the first molecular characterization of L. taurica on protected tomato in the Syrian coast. Keywords: Tomato, powdery mildew, Leveillula taurica, ITS.