SAC Research

What are resistance elicitors?

When a plant detects an invading micro-organism a complex series of events unfolds within minutes.

First, elicitor molecules of either plant or pathogen origin are released at the site of infection which, when recognised by the plant, trigger the production of signals. These signals then travel within the plant and are responsible for triggering a complex array of defence responses.

When recognition occurs quickly, the plant can effectively ‘resist’ pathogen attack. However, if there is a failure in recognition and defences are triggered too late, the plant succumbs to pathogen invasion and disease develops.

So, can we bypass this complex system of recognition and signal production and trigger defences when required? The answer is yes, and research in SAC and elsewhere has shown that it is possible to elicit resistance using either elicitor or signal molecules, or synthetic derivatives or mimics.

Research at SAC has:

• Shown that a range of naturally-derived and synthetic analogues can elicit resistance in barley to powdery mildew – these compounds trigger defence responses and reduce infection under controlled conditions.
• Demonstrated that these resistance elicitors are also effective in the field – application of resistance elicitors to barley crops twice in the season can reduce mildew infection by as much as 85 % and protect grain yield.

What next?

Research at SAC, in collaboration with SCRI, is now focussed on the conditions required in the field to achieve optimum performance of resistance elicitors.

Only by understanding how resistance elicitors are affected by genotype and cultural conditions and how they interact with other crop management practices will it be possible to use them effectively in practice.