Pathogen invasion at one site in a plant triggers defensive reactions throughout the rest of the plant. This systemic acquired resistance (SAR) is mediated by salicylic acid and the regulatory protein NPR1 and involves the activation of a suite of pathogenesis-related genes. Wang et al. found that another group of genes is activated and encodes the cellular secretory machinery. The same regulatory triggers set in motion production of antipathogen proteins as well as enhancing the means to deliver them to where they can do the most damage.
D. Wang, N. D. Weaver, M. Kesarwani, X. Dong, Induction of protein secretory pathway is required for systemic acquired resistance. Science 308, 1036-1040 (2005). [Abstract] [Full Text]