نخستین گزارش از Paramicrosphaeropsis eriobotryae همراه با بیماری شانکر انار

The pomegranate (Punica granatum L.) has garnered significant attention due to its wide adaptability, cold resistance, ability to thrive in low-yielding lands, and the substantial health benefits of its fruit. Iran is one of the largest pomegranate producers, competing closely with India and China. In Iran, pomegranates constitute nearly a quarter of global production, ranking as the fifth most significant horticultural product in the country. Fars province leads pomegranate production in Iran, yielding approximately 273,000 tons from 20,445 hectares of orchards. Canker disease is one of the most critical threats to pomegranate production. In recent years, there has been a notable increase in pomegranate diseases, including decline, dieback, and canker, affecting orchards worldwide. This study aimed to identify the fungal agents responsible for these diseases. Pomegranate trees exhibiting symptoms such as branch canker, dieback, and internal wood discoloration in Arsanjan and Shiraz counties, Fars Province, were examined. Preliminary morphological identification indicated that some fungal isolates from branch canker and dieback symptoms belong to an emerging ascomycete pathogen, Paramicrosphaeropsis eriobotryae, from the Didymellaceae family. Molecular identification using polymerase chain reaction (PCR) targeting the β-tubulin gene using primers Btub2Fd and Btub4Rd confirmed the morphological identification. This pathogen has also been implicated with canker and branch dieback in loquat trees. All isolates were inoculated onto detached branches of the Rabab cultivar. Statistical analysis of three pathogenicity traits including upward, downward, and horizontal lesion progression, was conducted to select the most aggressive isolate. The selected isolate was used in pathogenicity tests on one-year-old saplings of five different pomegranate cultivars. The susceptibility of the cultivars (Dane Siah Shahreza, Rabab, Saveh, Shahvar-e-Shirin, and Wonderful) to the most aggressive isolate was assessed through statistical analysis of five pathogenicity traits (upward, downward, and horizontal lesion progression, internal longitudinal progression of lesions, and the depth of wood discoloration(. Based on the results, Saveh and Wonderful cultivars were susceptible, Rabab and Shahvar-e-Shirin were semi-susceptible, and Dane Siah Shahreza cultivar was non-susceptible to this pathogen. This study represents the first global report of P. eriobotryae causing branch canker and dieback on pomegranate trees.