A team of international researchers has uncovered a mechanism by which plants are able to better defend themselves against disease-causing pathogens.

The work, led by Dr Jurriaan Ton and Dr Estrella Luna at the University of Sheffield, has identified the process by which a chemical called BABA can boost plant immunity. BABA has long been known for its protective effects against devastating plant diseases, such as potato blight, but has so far not been used widely in crop protection because of undesirable side effects.

"We have found that the plant receptor binding BABA is a [type of enzyme] which we have called IBI1. This class of enzymes play a vital role in primary metabolism of all cells, but had never been linked to immune responses in plants," Dr Luna said.

The chemical process in which BABA plays a part "triggers a secondary function that 'primes' the plant immune system against future attacks by pests and diseases," according to Dr Ton. Elaborating on the significance of the discovery, Dr Ton added, "Plant immunity that is controlled by a single resistance gene, on which most conventional breeding programs are based, is comparably easy to overcome by a pathogen. By contrast, priming of multi-genic immunity by BABA is difficult to break, thus offering more durable crop protection."

The Sheffield researchers made their breakthrough while working in partnership with colleagues in Australia, Spain and the Netherlands. Dr Oliver Berkowitz, a plant biologist from the University of Western Australia who was also involved in the research, commented, "Importantly, our study also revealed that the undesirable side effect of this vaccination, a reduction in growth, can be uncoupled from the beneficial immune reaction.

"Since plant immunisation by BABA is long-lasting, primed crops would require fewer applications of fungicides, thereby increasing sustainability of crop protection. Furthermore, immune priming boosts so-called 'multi-genic' resistance in plants."

Although the scientists' discoveries were made using the 'model' plant 'Arabidopsis thaliana', the team is confident that their discovery can be used for the protection of crops from their enemies. Proof-of-concept experiments have already shown that BABA is detected in a similar manner by tomato plants.