High Throughput Sequencing (HTS) has revolutionized the field of molecular virology, enabling the detection of many new viruses. With the HTS approach, black mulberry idaeavirus (BMIV) belonging to the genus Idaeovirus in the family Mayoviridae has been recently identified in sour black mulberry (Morus nigra L.) trees. The geographical distribution of this new virus is unknown and this study aimed to determine its prevalence in mulberries in Turkey. During the field studies, various symptoms were observed on M. nigra trees, such as the shortening of the fruit harvest period, the drying of fruits on the branches before full ripening, resulting in the near-total loss of fruits on the trees, and in some areas, the drying of branches. Within the scope of this study, 465 Morus spp. samples showing and not showing symptoms were collected from 44 cities in our country. The most collected species was M. nigra (a number of 378 out of 465), followed by 80 M. alba, two M. alba var. Pendula. The samples were tested using the RT-PCR method with three different primer pairs that amplify the partial sequence of BMIV (1643 nucleotides corresponding to 828-2470 nt of the RNA1 genome). While 87.5% of M. nigra samples were found to be infected with BMIV, only 26.25% of M. alba samples tested positive by RT-PCR. No infections were found in other Morus species. 167 of the samples that tested positive by RT-PCR were sent for sequencing. The findings indicate that BMIV shows high prevalence, particularly on M. nigra, and exhibits endemic spread in this species. The virus's ability to be transmitted through seeds, pollen, and vegetative material explains its rapid spread over a wide area.
