Concurrent detection of five Yellow dwarf viruses (B/CYDVs) in wheat in Mardin (Turkey) and phylogenetic relationship of BYDV-PAV

Wheat (Triticum aestivum L.) is a natural host of many viruses. Yellow dwarf viruses belonging to the Luteoviridae family are important virus species that cause economic loss by restricting wheat production worldwide. Surveys were conducted in 2017 to determine Yellow dwarf viruses (BYDV-PAV, BYDV-MAV, BYDV-SGV, BYDV-RMV, and CYDV-RPV) and their infection rates in wheat production areas in Mardin province. 400 fresh leaf samples collected were tested by  Multiplex reverse transcription-polymerase chain reaction (m-RT-PCR). The overall infection rate was found to be 3%. BYDV-PAV has been identified as the most widespread virus with a 2.5% presence rate. It was found out that BYDV-SGV, CYDV-RPV, and BYDV-RMV infections were lower, with rates of 1.75%, 0.5% and 0.25% respectively. In the current study, double infections were detected in 8 samples. The overall infection rate of the detected viruses (BYDV-PAV, BYDV-SGV, CYDV-RPV, BYDV-RMV) was found to be lower than the records reported in previous similar studies. No BYDV-MAV infection was found in any of the wheat samples tested. The cDNA of the coat protein (CP) gene of a BYDV-PAV isolate randomly selected from virus-positive samples was cloned, bidirectionally sequenced, and the phylogenetic relationship revealed. According to the phylogenetic analysis with 19 different isolates in the NCBI database of BYDV-PAV Mardin isolate, it showed the highest genetic similarity by 95.52% with the Germany isolate (KY634926) while the lowest similarity rate was 89.22% with the Germany and Pakistan isolates (KY634886 and JQ811489). The presence of BYDV-PAV, BYDV-SGV, CYDV-RPV, and BYDV-RMV were reported for the first time with this survey study conducted in Mardin.