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Pierluigi (Enrico) Bonello, The Ohio State University, Department of Plant Pathology; James T. Blodgett, Daniel A. Herms, |
Systemic resistance can be induced in many plants by pathogens, chemicals, and by some beneficial microorganisms such as specific Trichoderma fungi and bacteria that colonize roots. This is how composts can induce resistance to foliar diseases in some plants. It is a subtle but important effect. This phenomenon is termed Systemic Induced Resistance (SIR).
Extensive research has been carried out in the last 20 years, and particularly in the last decade, to understand SIR. Most of the work has been conducted on herbaceous model plants, particularly tobacco and Arabidopsis, as these systems are quite responsive to genetic manipulation (Buell, 1999). This has resulted in the development of chemical inducers of resistance such as Actigard. SIR-type responses have been observed in pine also (Bonello, Gordon, and Storer, 2001).
In contrast to the rather extensive studies in herbaceous plants, there are, to our knowledge, no detailed data on these processes for conifers other than the studies described herein. Only one example of chemical induction of resistance in pines is known (Reglinski, Stavely, and Taylor, 1998).