Transmission of Barley/Cereal yellow dwarf viruses by aphid vectors

Abstract

Barley and Cereal yellow dwarf viruses (B/CYDVs) negatively impact the fitness of host plants and have a destabilizing effect on established ecosystems. Plant and B/CYDV pathogen interaction dynamics can be significantly altered by increasing worldwide nitrogen and phosphorous input. Viruses rely on interactions between host plants, insect vectors and environmental factors in order to spread. Relationships between virus transmission and both the level of and ratio between host nitrogen and phosphorous resources are difficult to establish, especially in natural systems, and remain poorly understood. In order to assess the relationships between host resources and vectored-disease spread in controlled conditions, we developed a method of inoculation of healthy plants using aphid vectors that previously fed on virus infected fresh plant leaves. While we originally tested an inoculation method in which aphids fed on a homogeneous virus inoculum obtained by grinding and clarifying infected plant tissues, this resulted in low aphid survival and low virus transmission rate in our lab conditions. We will use the inoculation technique developed in this study to test the effects of host nutrient levels and ratios on virus transmission rate. The results obtained under laboratory conditions will allow us to make predictions on the broad connections between human nutrient loading and rates of viral infection.