In The Netherlands, Wageningen University researchers introduce a new class of potato resistance to combat late blight caused by Phytophtora infestans, a major threat to commercial potato production worldwide.

While genes for resistance to potato late blight have been identified and applied in potato breeding, the P. infestans population accumulates new strains that render these genes ineffective. The Wageningen team developed a new type of resistance through loss-of-function of susceptibility genes (S-gene). These S-genes encode gene products which are exploited by pathogens to aid them in plant infection.

The team selected 11 known Arabidopsis thaliana S-genes and silenced their ortholog S-genes in the susceptible potato cultivar Desiree. The silencing of each of the five genes resulted in complete resistance to the P. infestans isolate Pic99189, while silencing the sixth S-gene resulted in reduced susceptibility.

For more on the study, read the article in Transgenic Research.

Fig. 3

Plants and leaflets of three potato RNAi transformants compared with cv Desiree. a Potato cv. Desiree. b StDMR1-silenced transformant, showing a dwarf phenotype and light green leaves. c StDND1-silenced transformant showing auto-necrotic spots on older leaves. d StCPR5-silenced transformant showing dwarfing and light green leaves