Investigation on transmission of blueberry mosaic associated virus (BLMAV) by Olpidium spp. in bluberrien (Vaccinium spp.) and their possible roles on disease epidemiology

The production an consumption of blueberries (Vaccinum spp.) has recently been increased in Turkey however, it has been known and grown for many years in worldwide as an important crop. As other plant species, blueberries have also been infected by some important viruses, affecting yield and the quality. Among them, one of the most important one is bluberry mosaic assciated virus (BlMaV) which has been first time characterized in 2014 and detected in 2015 in Turkey. There has been no clear data about the natural transmission ways of BlMaV until recently. However, Olphidium spp. stated as potential vector for this virus due to it is the most common vector for Ophiovirus species and this hypothesis has been proven in 2017. The aim of this study is morphological and molecular characterization of Olpidium spp., which is the possible vector of the virus, present in the soil and BlMaV infected plant roots of the the wild and cultivated highbush blueberries growing in Rize province in Turkey and to study their potential roles on BlMaV transmission. According to the RT-PCR analysis by using primer pairs amplifying RNA3 gene of BlMaV in wild and cultivated blueberries collected from 3 different locations in Rize province, infection rate of BlMaV in tested samples of cultivated blueberries was 83% whereas it was 55% in wild blueberries. Among BlMaV infected locations, totally 17 soil samples from wild blueberry plantations (10 from Demirkapı, 7 from Anzer-Çiçekli) and 5 samples from the rhizospher of cultivated blueberry location were collected . Lettuce seedling as a trap plant for Olpidium spp. and in vitro propagated blueberry plants for BlMaV transmissibility were planted in these soils and experimental transmission trials were performed. Four weeks after plantings, the roots of both plant species were morphologically examined under microscope and resting spores of Olpidium spp were observed in both plant species. These results were confirmed by PCR analysis and only Olpidium virulentus was detected on both lettuce and blueberry roots by multiplex and species-specific PCR analysis. When lettuce and in vitro blueberry plants grown in soils collected from BlMaV infected, cultivated blueberry plantation (İkizdere) were tested for BlMaV by RT-PCR, the infection rate was 100% and 80% for blueberries and lettuce, respectively. The infection rate of BlMaV for lettuce and in vitro blueberry plants grown in soils collected from BlMaV infected wild blueberry plantations (Demirkapı and Anzer-Çiçekli) were found as 95% for blueberries and 62% for lettuce. As a result of this study, O.virulentus, which is regarded as the potential vector of BlMaV was detected by both morfological and molecular methods in 3 different locations in Rize province, where the most important blueberry production of our country is made and the virüs has been succesfully transmitted by O.virulentus to healty lettuce and blueberry seedling. This is the first study on the epidemiological aspect of BlMaV in Turkey and lettuce has been first time found as an experimental host for BlMaV for the world. 2020, 56 pages Key Words: Vaccinum spp., Rize, bluberry mosaic assciated virus, Olphidium spp