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Resistance

Effects of Localized Infections of Nicotiana tabacum by Tobacco Mosaic Virus on Systemic Resistance Against Diverse Pathogens and an Insect. John L. McIntyre, Associate and assistant plant pathologist, Department of Plant Pathology, The Connecticut Agricultural Experiment Station, New Haven 06504; J. Allan Dodds(2), and J. Daniel Hare(3). (2)Associate and assistant plant pathologist, Department of Plant Pathology, The Connecticut Agricultural Experiment Station, New Haven 06504; (3)Assistant entomologist, Department of Entomology, The Connecticut Agricultural Experiment Station, New Haven 06504. Phytopathology 71:297-301. Accepted for publication 21 July 1980. Copyright 1981 The American Phytopathological Society. DOI: 10.1094/Phyto-71-297.

In experiments that were performed simultaneously, tobacco mosaic virus (TMV) inoculation of a hypersensitive tobacco cultivar induced systemic and long-lived resistance against TMV, Phytophthora parasitica var. nicotianae (Ppn), and Pseudomonas tabaci. In separate experiments, TMV also induced resistance against Peronospora tabacina. Reproduction of the aphid, Myzus persicae was also reduced on TMV-infected plants. Resistance to Ppn, Ps. tabaci, and TMV was also induced by localized infections of tobacco necrosis virus. Systemic infections by cucumber mosaic virus, however, reduced only the number of lesions caused by TMV. Levels of protection and the time resistance developed in a given leaf were not the same for the different challengers. These results show that a single viral agent may induce resistance in tobacco against diverse challengers.