Plants have sophisticated ways to defend themselves against pests and diseases. The efficiency of this resistance depends on speed: the sooner a plant recognizes its attacker, the more effective its defence response will be.
Over the course of evolution, plants have acquired the ability to ‘prime’ their immune system in response to specific signals that indicate an imminent threat. This primed defence state enables a faster and/or stronger activation of basal defence mechanisms, thereby providing multigenic resistance against a wide range of diseases (1 – 4).
Broad-spectrum disease resistance through defence priming does not lead to major reductions in growth and reproduction (5). This makes the phenomenon attractive for sustainable crop protection because the opportunity exists to increase the efficiency of the plant immune system with little cost in terms of yield. Moreover, defence priming can be maintained over a relatively long period of time, and can even be transmitted to following plant generations (6). This is why defence priming is often regarded as a form of immunological plant memory. Despite its promising potential for application in crop protection, many aspects about the mechanisms underpinning defence priming remain unresolved.
Our current research focuses on four aspects of defence priming:
Induction of the ‘primed’ defence state: what signalling events enable primed plants to express a more efficient immune response against attackers?
Maintenance of the ‘primed’ defence state: what are the mechanisms behind the longevity of defence priming, including the intriguing phenomenon that priming can be transmitted to following plant generations without genetic changes?
Mechanisms by which plants recruit root-colonizing soil microbes that induce defence priming in the shoot.
1. Ahmad S et al. & Ton J (2010) Mol Plant Pathol 11: 817-827. 2. Heil M & Ton J (2008) Trends Plant Sci 13: 264-272. 3. Priming Workgroup (2006) MPMI 19: 1062-1071. 4. Pastor V et al. & Ton (2013) Environ Exp Bot in press. 5. Van Hulten M et al. & Ton J (2006) PNAS 103: 5602-5607. 6. Luna E et al. & Ton J (2012) Plant Physiol 158: 844-853.