Identification of candidate insect vectors of Grapevine red blotch virus by means of an artificial feeding diet

Abstract

The ability of an insect to vector a plant virus has traditionally been determined through controlled greenhouse transmission experiments that are notoriously resource- and time-consuming and of unreliable outcome. Therefore, before committing to these protracted experiments, it is important that researchers identify biologically viable candidate vectors. This study presents an approach for identifying potential insect vectors of circulative plant viruses that significantly reduces the time-to-results while also reducing costs and required resources. This artificial transmission protocol, using a buffered sucrose solution as the virus recipient in place of a living plant, also eliminates plant-to-plant variation in susceptibility to infection, allowing assessment of virus–insect compatibility required for successful transmission of persistent viruses. To validate this approach, species of hemipteran insects, including leafhoppers, froghoppers, aphids, sharpshooters, and treehoppers, were subjected to an artificial feeding system to determine their ability to vector the emerging Grapevine red blotch virus (GRBV) (family: Geminiviridae). Test insects were allowed to feed on a potted grapevine infected with GRBV for 3 days and then transferred to tubes containing the sucrose solution partitioned by a thinly stretched Parafilm™ membrane. After 3 days of feeding through the membrane, viruliferous test insects were stored for species identification and the sucrose solutions were tested by conventional polymerase chain reaction for the presence of GRBV DNA. Out of all the insects tested (n = 395) only nine treehoppers from two different species successfully transmitted GRBV to the sucrose solutions, indicating a high likelihood of vector capability, to be validated by greenhouse or field experiments.