Multi-stacked Resistance Genes Confer Broad Spectrum Late Blight Resistance in Potato

Late blight is one of the notorious diseases in potato caused by fungi Phytophthora infestans. Previous studies have found that the Mexican potato species Solanum demissum is a good source of resistance genes against late blight. Scientist Hyoun-Joung Kim of Wageningen University and Research Center in Netherlands, together with the other researchers, conducted a study to get more information about resistance genes R8 and R9 which have shown broad spectrum resistance in both laboratory and field conditions. They crossed Mastenbroek (Ma) R8 and R9 clones to susceptible plant and subjected the parents and offsprings to pathogen recognition specificities, detached leaf assays, and gene-specific markers.

Four resistance genes were detected in MaR8 while seven were found in MaR9. They found that stacking of many R genes strongly delayed the onset of late blight symptoms. It was notable that the plant with only R8 as resistance gene conferred a delay that is similar with plants containing multiple resistance genes.

The scientists concluded that the "de-stacking" approach is useful in generating resistance gene combinations that could contribute in future studies involving development of new late blight resistant varieties.

Read the abstract at http://www.springerlink.com/content/52x881847733m058/.