Abstract
Yellow dwarf viruses (YDVs) are widespread and most economically important virus diseases in cereal growing areas in the world and Turkey. Because of the global climate changes, prevailing higher temperatures cause an epidemic of YDVs, transmitted by aphid vectors, are reduced yield and quality in cereal species, especially on winter bread wheat. In this study, 808 weed samples belonging to annual and perennial 52 weed species in the Poaceae family and other 5 different families in the cereal growing areas in Edirne, Kırklareli, and Tekirdağ provinces of the Trakya region were collected to determine the inoculum sources weed species is one of the factors that cause epidemics of YDVs. In the cereal growing areas of Trakya, in the borders of cereal fields and in grassland exhibiting yellowing, reddening, and stripe mosaic symptoms and asymptomatic 808 weed samples were screened by serological and molecular methods for the presence of Barley yellow dwarf virus-PAV (BYDV-PAV), BYDV-MAV, BYDV-SGV, BYDV-RMV and Cereal yellow dwarf virus-RPV (CYDV-RPV). Moreover, in this study diagnosed 7 aphid species that vectors of YDVs, 132 intact weed plants with aphid colonize belonging to 14 weed species, were used for the transmission experiments and were tested 206 symptomatic indicator plants by ELISA and RT-PCR. The screening tests showed that 535 out of 808 weed samples found infected with YDVs. Both method results revealed that the infection rate of 23.8% with BYDV-PAV, 10.4% BYDV-MAV, 6.8% with CYDV-RPV, 1.1% with BYDV-SGV, and 0.7% with BYDV-RMV as a single infection. However, the coinfection rate was 23.3%. A total of 181 YDVs isolates were sequenced and classified phylogenetically with the other YDVs isolates in the Genbank database. As a result of this study was identified 40 out of 52 weed species infected with YDVs that were Avena sterilis, Avena fauta, Lolium rigidum, Bromus sterilis, Hordeum murinum, Phragmites austrialis which play an important role epidemic of YDVs in the cereal growing areas as a crucial reservoir weed hosts.