Disabling Instead of Adding: A Novel Way of Breeding Disease-Resistant Plants

Researchers at the Wageningen UR in the Netherlands are focusing on a novel strategy for breeding plants resistant to diseases: disabling genes instead of adding resistance genes. Turning off the expression of genes using molecular techniques have been used for many years to improve crop quality, but according to the Wageningen researchers, it has not been used to increase resistance of crops to pathogens in order to mimic recessive mutations. Wageningen professors Yuling Bai, Evert Jacobsen and Richard Visser explain this approach in a review article published by Molecular Breeding.

In the paper, Bai and colleagues discussed the latest findings on plant factors that are activated by pathogen effectors to suppress plant immunity, the so-called susceptibility genes. The first susceptibility gene, called Mlo, was found in barley. This gene was found to be non-functional in powdery mildew-resistant plants. Silencing Mlo in Arabidopsis resulted to plants that can resist the disease.

The new breeding strategy is still controversial among plant scientists and breeders, according to the scientists. "We have already been discussing this strategy for two and a half years," said Jacobsen. "Not everybody is convinced of its potential. People say: gene silencing is old, we need resistance genes. But you have to investigate new techniques and strategies - that's the task of a university." Jacobsen and his team is now investigating the genes in potato involved in late blight susceptibility.

Read the original story at http://www.wur.nl/UK/newsagenda/news/Novel_breeding_strategy_for_plant_resistance.htm The paper is available for download at http://dx.doi.org/10.1007/s11032-009-9323-6