Submitted to: Archives of Virology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/30/2006
Publication Date: 5/20/2007
Citation: Robertson, N.L., French, R.C. 2007. Genetic structure in natural populations of barley/cereal yellow dwarf virus isolates from Alaska. Archives of Virology. 152(5):892-902. Interpretive Summary: Barley yellow dwarf virus (BYDV)-PAS, -PAV, and Cereal yellow dwarf virus (CYDV)-RPV are three plant viruses that cause yellow dwarf disease in oats and barley in Alaska. Because BYD is the most destructive virus disease in grass and cereals, we were interested in obtaining and analyzing genetic information from a large number of isolates to help us understand the population structure for BYDV-PAS, -PAV, and CYDV-RPV within and between fields during 2002-2004, and how they are related to other plant viruses throughout the world. The majority (80%) was similar to the New York BYDV-PAS isolate (formerly PAV 129), nearly 17% were similar to CYDV-RPV, and about 3% resembled the New York BYDV-PAV isolate. Eleven CYDV-RPV isolates were genetically unique. Isolates from the same fields were generally as variable as the total population. Genetic makeup of the isolates remained the same over the three years of observation and there was no host (barley or oats) preference among the isolates. The overall significance of a genetically stable B/CYDV populations in Alaska will benefit plant breeders who examine host resistance for barley yellow dwarf disease in Alaska.
Technical Abstract: The genetic structure of natural populations of Alaskan Barley yellow dwarf virus (BYDV)-PAV, BYDV-PAS, and Cereal yellow dwarf virus (CYDV)-RPV from barley (Hordeum vulgare) and oats (Avena sativa) in Alaska were analyzed between 2001-04. PCR products spanning the viral coat protein gene of 186 isolates were cloned and sequenced. The majority (80%) was similar to the New York BYDV-PAS isolate (formerly PAV129), nearly 17% were similar to CYDV-RPV, and about 3% resembled the New York BYDV-PAV isolate. The CYDV-RPV isolates clustered in three groups: 42%, resembled RPV isolates from Mexico, 15% resembled the New York RPV isolate, and 33% formed a group distinct from all currently available CYDV sequences. The mean within-group sequence diversities were less than one percent for each of the PAS, PAV, and RPV genotype clusters. The patterns of genetic variation of PAS and RPV populations varied little over time or with respect to host plant. Over 90% of the total variation was accounted for by differences among isolates within individual fields. The difference in spatial and temporal population genetic structures of the PAS and RPV isolates suggested that the two viral species are influenced by different agroecological factors.