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Four commercial ELISA kits for serological detection of Citrus tristeza virus (CTV) were evaluated under uniform laboratory conditions. All four kits were efficient for discrimination of positive and negative CTV samples. Optical density (OD405) values after 120 min of hydrolisis of p-nitrophenyl phosphate (pNPP) for 16 CTV isolates were between 0.290 and 1.386 (X = 0.997) for Agdia kit, between 0.163 and 1.590 (X = 0.977) for Bioreba, between 0.250 and 2.049 (X = 1.367) for Ingenasa, and between 0.250 y 2.023 (X = 1.183) for Sanofi. For healthy controls after 120 min of hydrolysis of pNPP, Ingenasa and Sanofi kits yielded OD405 readings lower than 0.100; whereas, the kits from Agdia and Bioreba yielded values between 0.100 y 0.150, respectively. According to these results, the four kits can be reliably used for the serological detection of CTV. The selection of any of them would be based upon cost and product availability. Results of this study are also useful for any research work with CTV, but mostly for those certified laboratories devoted for the routine detection of CTV in Mexico. [ABSTRACT FROM AUTHOR]

An in situ immunoassay is described for localization of Citrus tristeza virus (CTV) inclusion bodies by light microscopy with antibodies developed to the recombinant p20 non-structural protein. Free hand bark sections of ca. 100 μm tick from healthy or CTV infected plants were fixed with 70 % ethanol and subsequently incubated with specific polyclonal antiserum anti-p20 either from rat or rabbit at dilutions 1:5,000 y 1:10,000 y 1:1,000 and 1:3,000 respectively and IgG anti species at 1:30,000 dilution; at the end, the chromogenic solution NBT/BCIP was added. Viral inclusion bodies were visualized by light microscopy at 10 and 40X magnifications as dark blue irregular areas in phloem associated tissues in CTV infected plants; no dark blue color was observed in the phloem tissues of healthy plants. [ABSTRACT FROM AUTHOR]