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Inhibitory Effects of a Polyphenol-Polyphenol Oxidase System on the Infectivity of Cowpea Chlorotic Mottle Virus Ribonucleic Acid. T. L. Woods, Graduate Research Assistant, Department of Plant Pathology, University of Massachusetts, Amherst 01002; G. N. Agrios, Associate Professor, Department of Plant Pathology, University of Massachusetts, Amherst 01002. Phytopathology 64:35-37. Accepted for publication 19 June 1973. DOI: 10.1094/Phyto-64-35.

Solutions of enzymatically oxidized L-β-3, 4-dihydroxyphenylalanine (L-DOPA), chlorogenic acid, and catechol reduced the infectivity of cowpea chlorotic mottle virus ribonucleic acid (CCMV-RNA) as compared with the unoxidized phenolics, polyphenoloxidase only, and buffer controls. RNA infectivity decreased as the length of time the RNA was exposed to the oxidized phenolics increased from 0 to 60 min, or as the temperature of the reaction mixture increased from 0 C to 35 C. Oxidized chlorogenic acid reduced infectivity more effectively than either oxidized catechol or oxidized L-DOPA. Polyphenoloxidase (PPO) reduced the infectivity of CCMV-RNA by nearly 70% in 20 min at 23 C. Solutions of boiled PPO, bovine serum albumin (BSA), and boiled BSA, had little effect on RNA infectivity. Treatment of PPO with bentonite did not restore the infectivity of RNA to the level of the buffer control. It is suggested that the effects of oxidized phenolics on the infectivity of CCMV-RNA may be due to reactions between amino groups present on the RNA molecules and quinones.

Additional keywords: tyrosinase, RNase.