Abstract: | The PR protein-inducing effect of naturally-occurring physiologicaldisorders of tobacco (sharilka, due to water excess,and Mn toxicity) was established. This supports the view ofPR proteins as stress macromolecules rather thanexclusively pathogenesis-related macromolecules. The effectsof the physiological disorders were compared with those of PVYN-infection;all these treatments produced similar symptoms of necrotic spottingon leaves. It was demonstrated that non-pathogenic (physiological)necrobiosis induced the same PR proteins as did infectious necrobiosis. Key words: PR proteins, tobacco, physiological disorders |