A Possible Explanation of the Resistance of Virus-infected Tobacco Plants to Second Infection

Abstract

SUMMARY Leaves of tobacco plant cv. Xanthi-nc inoculated or systemically infected with potato virus Y, cucumber mosaic virus, potato virus X, potato aucuba mosaic virus or alfalfa mosaic virus showed varying degrees of resistance to infection with tobacco mosaic virus. The resistance was correlated with the appearance of at least three proteins not present in healthy plants. These were the proteins that appear in leaves injected with polyacrylic acid. Both the resistance to second infection and proteins decreased when the plants were kept for 2 days before inoculation at 32 °C.