title: Biometrical genetic analysis of luteovirus transmission in the aphid Schizaphis graminum.
abstract: The aphid Schizaphis graminum is an important vector of the viruses that cause barley yellow dwarf disease. We studied the genetic architecture of virus transmission by crossing a vector and a non-vector genotype of S. graminum. F1 and F2 hybrids were generated, and a modified line-cross biometrical analysis was performed on transmission phenotype of two of the viruses that cause barley yellow dwarf: Cereal yellow dwarf virus (CYDV)-RPV and Barley yellow dwarf virus (BYDV)-SGV. Our aims were to (1) determine to what extent differences in transmission ability between vectors and non-vectors is due to net additive or non-additive gene action, (2) estimate the number of loci that determine transmission ability and (3) examine the nature of genetic correlations between transmission of CYDV-RPV and BYDV-SGV. Only additive effects contributed significantly to divergence in transmission of both CYDV-RPV and BYDV-SGV. For each luteovirus, Castle-Wright's estimator for the number of effective factors segregating for transmission phenotype was less than one. Transmission of CYDV-RPV and BYDV-SGV was significantly correlated in the F2 generation, suggesting that there is a partial genetic overlap for transmission of these luteoviruses. Yet, 63% of the F2 genotypes transmitted CYDV-RPV and BYDV-SGV at significantly different rates. Our data suggest that in S. graminum, the transmission efficiency of both CYDV-RPV and BYDV-SGV is regulated by a major gene or set of tightly linked genes, and the transmission efficiency of each virus is influenced by a unique set of minor genes.
authors.affiliation: USDA-ARS Plant Protection Research Unit, Department of Plant Pathology, Cornell University, Ithaca, NY 14853, USA.
authors.forename: M E
authors.initials: ME
authors.lastname: Burrows
authors.forename: M C
authors.initials: MC
authors.lastname: Caillaud
authors.forename: D M
authors.initials: DM
authors.lastname: Smith
authors.forename: S M
authors.initials: SM
authors.lastname: Gray
mesh_terms: D000818:Animals; D001042:Aphids / Q000235:genetics* / Q000821:virology*; D003433:Crosses, Genetic; D017344:Genes, Insect; D005838:Genotype; D001467:Hordeum / Q000378:metabolism; D007303:Insect Vectors / Q000235:genetics* / Q000821:virology*; D017793:Luteovirus; D010641:Phenotype; D014908:Triticum / Q000378:metabolism