اولین گزارش از وقوع گونه Ampelomyces quisqualis، میکوپارازیت Golovinomyces sonchicola، روی میزبان شیرتیغک Sonchus asper

Pycnidial fungi belonging to the genus Ampelomyces are one of the most widespread and oldest natural enemies of the Erysiphaceae. In the continuation of the studies for precise identification of the mycoparasites of powdery mildew fungi, the species diversity of the genus Ampelomyces on some host plants of powdery mildews was studied in Isfahan, Chaharmahal & Bakhtiari and Ardabil provinces during 2022-2023. After collection of Sonchus asper which infected with powdery mildew from Chaharmahal & Bakhtiari province and transferred to the Royan Plant Clinic & Lab, first host powdery mildew fungus (Golovinomyces sonchicola) was identified based on morphology, host plant and ITS nrDNA sequences. It is worth mentioning that pycnidia of Ampelomyces are commonly found inside the hyphae, conidiophores, conidia and immature ascomata of powdery mildew fungi. The dimensions of pycnidia were determined before isolation using light microscopy. One or two pycnidia were removed with sterile hand-made glass needles from the mildew mycelia and were put on Czagar culture medium. Cultures were incubated at 25 °C in the dark condition for 14 days. Then, the micromorphological and growth characteristics of the cultured isolates, including the shape and size of the pycnidia (3.4-1.7 µm) and the measurement of the radial growth of the isolates (271 mm2) examined after two weeks and compared with reliable sources. Moreover, ACT (actin gene) of mycoparasite isolates was partially sequenced and compared with reliable sequences in GenBank. Based on these studies, Ampelomyces quisqualis is recorded for the first time as a mycoparasite of Golovinomyces sonchicola, the causal agent of powdery mildew on Sonchus asper.