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Oxidising activity in root extracts from plants inoculated with virus or buffer that interferes with ELISA when using the substrate 3,3‘, 5,5’‐tetramethylbenzidine
Author(s) -
JONES A. T.,
MITCHELL MARGARET J.
Publication year - 1987
Publication title -
annals of applied biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.677
H-Index - 80
eISSN - 1744-7348
pISSN - 0003-4746
DOI - 10.1111/j.1744-7348.1987.tb01463.x
Subject(s) - conjugate , biology , substrate (aquarium) , petunia , cucumber mosaic virus , antiserum , inoculation , plant virus , peroxidase , virus , horseradish peroxidase , chenopodium , alfalfa mosaic virus , botany , enzyme , biochemistry , horticulture , virology , coat protein , antibody , mathematical analysis , ecology , mathematics , rna , immunology , weed , gene
SUMMARY In indirect ELISA using protein A‐horseradish peroxidase (HRP) as enzyme conjugate and 3,3′, 5,5′‐tetramethylbenzidine (TMB) as substrate, extracts of roots of all cucumber, Chenopodium quinoa and Petunia hybrida plants previously inoculated with virus or buffer produced A 450 values up to seven‐fold greater than those for comparable shoots or for extracts of roots from undisturbed, uninoculated plants, irrespective of the virus antiserum used for detection. This effect was also produced in tests in which no HRP conjugate was used, indicating that root extracts from virus‐infected or physically injured plants, but not healthy uninjured plants, contain high levels of a factor able to oxidise TMB. The HRP conjugate/TMB substrate version of ELISA is therefore not reliable for detecting viruses in root extracts of herbaceous plants. In contrast, non‐specific reactions were not obtained with root extracts, and viruses were reliably detected, when protein A‐alkaline phosphatase was used as conjugate and p ‐nitrophenyl phosphate as substrate.