Citrus Tristeza Virus - Diagnosis

Diagnosis

CTV is classically diagnosed by graft-inoculating a Mexican lime (Citrus aurantifolia) with tissue from a diseased plant. The Mexican lime will develop highly predictable symptoms. Symptoms on the leaves begin as clear veins that turn corky, which is then followed by chlorosis and cupping of the leaf. Particularly severe strains may result in stunting, and stem-pitting may also occur. Alternatively CTV can be indicated by the presence of aggregates of cross-banded inclusion bodies in the phloem of the diseased plant. Other diagnostic procedures include electron microscopy, double-antibody sandwich enzyme-linked immunosorbent assay (DAS-ELISA), tissue-print ELISA, and PCR-based assays. These methods identify signs of the virus, such as its microscopic structure (electron microscopy), the presence of its proteins’ antigens (ELISA) or the presence of its RNA (PCR).