Plant biology

Secondary Messenger

Science Signaling  07 Apr 2009:
Vol. 2, Issue 65, pp. ec123
DOI: 10.1126/scisignal.265ec123

How do plants prime themselves to resist systemic pathogenic infections? Jung et al. report that a small mobile metabolite molecule, azelaic acid, found in Arabidopsis leaves, can contribute to defense priming during systemic acquired resistance to pathogens. Levels of azelaic acid increased in plants exposed to pathogens and triggered systemic resistance. When pure azelaic acid was sprayed onto leaves, it induced systemic resistance in wild-type but not in systemic resistance–deficient mutants. Furthermore, azelaic acid stimulated the production of the systemic signaling molecule salicylic acid, consistent with a priming effect. The findings help to explain why salicylic acid is required both in locally infected tissue and in the distal tissue that will develop systemic acquired disease resistance, yet is not itself mobile.

H. W. Jung, T. J. Tschaplinski, L. Wang, J. Glazebrook, J. T. Greenberg, Priming in systemic plant immunity. Science 324, 89–91 (2009). [Abstract] [Full Text]