A central role of salicylic acid in plant disease resistance. - Delaney, ,T..P.,.; Uknes, ,S.,.; Vernooij, ,B.,.; Friedrich, ,L.,.; Weymann, ,K.,.; Negrotto, ,D.,.; Gaffney, ,T.,.; Gur-Rella, ,M.,.; Kessmann, ,H.,.; Ward, ,E.,.; and Ryals, ,J.. (Science, 1994)