Trakya Region of Turkey has been one of the important cereal growing areas in Turkey. Previously sporadic and
temporary infections of Yellow dwarf viruses (YDVs) have been reported in some parts of Turkey. YDV diseases on
cereals however have been prevailing and causing yellowing, dwarfing, reddening and the reduction of grain yield on
cultivated cereals since 1999 in the Trakya Region. YDV have been identified and their incidence and the rate of infections
were investigated. Barley yellow dwarf virus-PAV (BYDV-PAV) was diagnosed as the most virulent and dominant one
as Cereal yellow dwarf virus-RPV (CYDV-RPV) was also identified as another important virus in the area. In order to
determine sources of YDVs and their over summering and overwintering hosts among the Poaceae weed species 326
symptomatic weed leaf samples and 82 intact weed plants were collected from road sides and hedge grows of cereal
fields in 2010. In second year 357 weed leaf samples, 13 voluntary cereal leaves and 50 intact weed plants were also
collected from same sites. Separately 7 aphid species were identified and 5 of them were used for vector transmission
tests of YDVs from potted intact weeds to indicator barley (cv. Barbaros) seedlings. As a result of aphid transmissions
from 15 weed species, 156 symptomatic barley leaf samples and from 6 weed species, 50 symptomatic barley samples
were obtained in 2010 and 2011 respectively. So, totally 902 leaf samples were obtained from 42 weed, 3 voluntaries and
1 indicator barley species. DAS-ELISA and RT-PCR tests on 326 weed samples revealed the corresponding incidence
rates were 54.60% for BYDV-PAV, 7.05% for CYDV-RPV, 5.52% for PAV+RPV, 14.41% for the other YDVs and
being 81.59% total rate of virus incidence in weed samples in 2010. Test results on 370 leaf samples also revealed the
incidences of BYDV-PAV as 14.86%, CYDV-RPV as 10.81%, PAV+RPV as 7.56% and the other YDVs as 48.91%
totally being 82.16% rate of virus incidence from weed and voluntary cereal samples in 2011. Aphid transmitted barley
samples revealed the similar incidences of viruses too. For molecular characterization the genomic region containing
coat protein (CP) regions of BYDV-PAV and CYDV-RPV were amplified from selected weed species and samples by
RT-PCR method. Specific DNA fragments in the sizes of 531 bp and 400 bp were amplified from 45 BYDV-PAV isolates
from 24 weed species and 34 CYDV-RPV isolates from 15 weed species respectively. The selected DNA fragments of
BYDV-PAV and CYDV-RPV were purified and sequenced for the determination of nucleotide sequences of CP genes
of both virus isolates. Partial nucleotide sequences of 20 Turkish PAV weed isolates were determined and compared
with other nine BYDV-PAV isolates in databases. Phylogenetic analysis of obtained and published nucleotide and amino
acid sequences revealed the identity ranged from 86.67 - 99.80% and 70.05 - 99.40% respectively. Partial nucleotide
sequences of 6 CYDV-RPV isolates were also compared with seven isolates of CYDV-RPV isolates in GenBank⁄EMBL.
The nucleotide and amino acid sequences revealed the identity ranged from 80.44 - 95.86% and 62.50 - 93.33% identities
respectively. To our knowledge, this is the first report of YDV’s in Poacea weed hosts in Turkey.
Primary Language | English |
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Journal Section | Articles |
Authors | |
Publication Date | July 31, 2018 |
Published in Issue | Year 2018 Volume: 4 Issue: 2 |