Induction by Salicylic Acid of Pathogenesis-related Proteins and Resistance to Alfalfa Mosaic Virus Infection in Various Plant Species Hooft Van Huijsduijnen, R. A. M. and Alblas, S. W. and De Rijk, R. H. and Bol, J. F.,, 67, 2135-2143 (1986), doi = https://doi.org/10.1099/0022-1317-67-10-2135, publicationName = Microbiology Society, issn = 0022-1317, abstract= Summary Spraying tobacco plants with salicylic acid induces both the synthesis of ‘pathogenesis-related’ (PR) proteins and resistance to viruses that can induce necrotic lesions. We show that spraying Samsun NN tobacco with salicylic acid induced the production of PR-1 mRNAs and inhibited the systemic multiplication of alfalfa mosaic virus (AlMV) by 90%. Salicylic acid treatment also induced the synthesis of PR proteins in bean and cowpea plants, and reduced by 75% the production of local lesions in AlMV-infected bean plants. Salicylic acid inhibited the replication of AlMV in cowpea protoplasts by up to 99%, depending on the mode of application. In AlMV-inoculated cowpea protoplasts, the production of viral minus-strand RNA, plus-strand RNA and coat protein was abolished, indicating that salicylic acid inhibits an early step in the AlMV replication cycle. The viability of the cells and the synthesis of host proteins were not affected by salicylic acid. Another aromatic compound, p-coumaric acid, induced neither PR proteins nor resistance to virus infection., language=, type=