اولین گزارش قارچ اندوفیت Syncephalastrum racemosumاز جلبک کاهو دریایی (Ulva sp.) در دنیا

The study aimed to isolate and identify endophytic fungi from marine lettuce seaweed (Ulva sp.). The Syncephalastrum genus belongs to the Mucorales order. According to the Index Fungorum system (www.indexfungorum.org), the Syncephalastrum genus is composed of two species: S. racemosum and S. monosporum. The samples were surface disinfected using a multi-stage disinfection method including 70% ethanol (1 minute), once washing with sterile distilled water, again 70% ethanol (15 seconds) and three times washing with sterile distilled water. To confirm the correct disinfection of the surface of the last washing water, the samples were cultured on PDA culture medium. After drying, the samples were divided into small pieces and cultivated in PDA medium containing Sea lettuce extract (200 ml/liter). They were then kept in an incubator at 25 degrees Celsius for 3 weeks. The grown isolates were purified by the thread tip method. In this research, 3 isolates were isolated. The lack of growth of fungi in Petri dishes cultured with water from the third wash showed the effectiveness of surface disinfection. Identification of the isolates was done based on the morphological characteristics and the sequence of the ITS region. Based on the morphological characteristics of these isolates, they produced a significant amount of aerial mycelium on the PDA culture medium, which grew very rapidly. The color of the colony was white at first and turned into dark gray and then black as a result of sporulation. They produced straight, simple to branched sporangiophores (diameter 3-4 micrometers), which were spherical to oval vesicles (diameter 11-16 micrometers) brown in color. Directly on their surface were sporangia. The radial face consisted of cylindrical rows containing 1-8 sporangiospores. Sporangiospores with smooth walls were Ovoid, Spherical, Oval, Cylindrical and other various shapes (2-6 µm in diameter). Using the primers ITS1 and ITS4, a 621 base pair fragment was amplified for the desired isolate.The sequence of the desired isolate had 100% nucleotide similarity with the sequence of the isolate with S. racemosum species. The examination of the morphological features combined with the results of the ITS sequencing analysis confirmed that the isolated fungal samples belong to the fungus S. racemosum. The fungal species identified in this research is reported for the first time in Iran and the world from the algae Ulva sp. The evolutionary relationship of the studied isolate with the isolates of this species and other species of the Syncephalastrum genus available in the Genebank and authoritative articles is being completed and will be published in future reports.