شناسایی فنوتیپی و مولکولی باکتری عامل پوسیدگی زعفران در استان‌های خراسان

Saffron, Crocus sativus, is a perennial plant belonging to the Iridaceae family that is gain popularity both as a medicine and as a spice. Known as the "red gold of Iran," saffron is the most valuable agricultural product and the most expensive spice in the world, holding a special place in the country's export history. However, recent investigations have revealed the emergence of several bacteria from different genera in Iran, leading to saffron root rot. Without accurate and timely studies, this disease could spread further, posing a serious threat to this strategic product. In order to identify the bacteria responsible for saffron rot, samples were collected from infected saffron plants' from the corm (with signs of necrosis and rot), stem (with signs of suffocation) and leaves (with signs of burnt water on the leaf sheath) of infected saffron plants during the years of 2023-2024 from Faruj (North Khorasan)Kalat, Torbat Heydarieh, Darghz and Neishabur (Razavi Khorasan) and Ferdous, Qain, Beshroieh (South Khorasan) and sample collection, isolation and purification processes were performed. In the next stage, the pathogenicity test of 40 isolates obtained on the geranium plant and edible onion of yellow variety Dayan Flat was performed and 17 pathogenic isolates caused leaf spot on the geranium plant and rotting at the place of bacterial injection on the edible onion. They were selected to perform identification tests. To identify the phenotypic characteristics of the selected pathogenic bacteria, Gram tests, oxidase, catalase, O/F, fluorescent pigment production, potato starch, arginine dehydrolase, the ability to grow bacteria at 40°C were performed and in order to ensure the presence of isolates Bacillus among the isolates, the growth ability of this bacterium was determined after placing its suspension in a hot water bath at 80°C for 10 minutes. Initial morphological and biochemical examinations indicated that these isolates belong to the genera Bacillus, Burkholderia, and Pseudomonas. Molecular identification of one of the patient isolates with general primers that amplify the S-rRNA16 region showed that this bacterium belongs to the Pseudomonas abietaniphila species with 99.41% similarity. More studies are being conducted to accurately identify the isolate using multiple gene locus tests (MLSA).