Western blot detection of the CSDaV CPs from the crude protein extracts of CSD-affected and unaffected citrus trees. Recombinant CPs His-p22.5 (p22.5) and NFp21 (p21) were used as standards. Lanes A, B, C, and D correspond to crude protein extracts obtained from CSD-affected citrus trees. Lanes E, F, and G correspond to crude protein extracts of unaffected citrus trees. A mixture of antisera obtained against synthetic peptides was used for this immunoassay. The recombinant p22.5 (His-p22.5) runs at 24 kDa, because it was fused to a His tag and thrombin site at the N terminus.