1a.Objectives (from AD-416):
1. Characterize biomarker genes in three types of sucking insects (aphids, leafhoppers, and whiteflies).
2. Determine if the biomarkers can be used as an effective tool to rapidly identify the risk of virus transmission in insect populations.
1b.Approach (from AD-416):
An ARS laboratory (Biological Integrated Pest Management Unit, Ithaca, New York) recently discovered protein biomarkers in greenbug aphids (Schizaphis graminum) that were used to identify aphid populations that were efficient vectors of yellow dwarf disease in cereal crops. This is the first agricultural application of protein biomarkers. The biomarkers may be a useful tool for predicting the threat of an insect population to disease-causing agents. It is not known if the predictive capacity of these biomarkers for circulative viral transmission may extend to other aphids, whiteflies, and leafhoppers. Collaborative research will be conducted on three groups of sucking insects (aphids, whiteflies and leafhoppers) and selected associated plant viruses. The research team will identify and characterize biomarker genes in aphids, whiteflies and leafhoppers. Selective reaction monitoring (SRM) will be used to develop field-based assays that predict the vectoring ability of an insect population. The ARS co-PI will be responsible for collecting and developing isofemale lines of the B-biotype sweetpotato whitefly, and the transmission of different whitefly populations will be assayed for infectivity of the Sweet potato leaf curl virus (SPLCV) as a Geminivirus model. Viruliferous whiteflies from a culture of SPLCV will be used to inoculate healthy plants. Transmission efficiencies will be determined for each population; preserved insect samples will be sent to the collaborating laboratories for characterization of genes encoding biomarker proteins. Parallel assays will be conducted by collaborators with the other insect groups and other viruses.
This research relates to inhouse project Objective 3: Identify whitefly-host plant-virus relationships and develop methods for protection from the whitefly-vectored viruses of vegetables such as sweetpotato and watermelon. All experiments focus on identitying whitefly-host, plant-virus relationships and developing methods for the protection of vegetables from whitefly-vectored viruses. A culture of the sweetpotato leaf curl virus (SPLCV) was isolated from sweetpotato and was maintained on plants in the laboratory. Several colonies of the sweetpotato whitefly from different origins were established and maintained in the laboratory. These whiteflies were from the field and greenhouse, and some colonies were from siblings with the same parents. Assays are being conducted on SPLCV transmission and how it is affected by levels of virus infection in the transmitting whitefly population.