Microarray immunoassay for the detection of grapevine and tree fruit viruses

Development and application of DNA microarrays for plant disease diagnosis has to date been limited, and for antibody arrays even more so. In this work, an antibody microarray procedure was developed and its usefulness for the detection of plant viruses demonstrated. Using the conventional monoplex immunoassay ELISA technique as a benchmark, the procedure was used to detect several grapevine and tree fruit viruses. In a direct labelling approach, Arabis mosaic virus (ArMV), and Grapevine fanleaf virus (GFLV) were detected after incubating the antibody array with alkaline phosphatase-conjugated viral extract. Indirect detection using a double or triple antibody sandwich format also resulted in good reaction signals, using either a chromogenic or fluorescence dye. In a multiplex system, four grapevine viruses were detected without compromising sensitivity and specificity. Compared to ELISA, the antibody microarray system is similar with respect to sensitivity and specificity, and a high correlation (R2, 0.759) was observed in regression analysis of virus concentration measurements. Receiver operating characteristic (ROC) curve analysis provided evidence of the good performance of the microarray system (AUC > 0.8).