Towards synthetic disease resistance genes

GIANNAKOPOULOU, ARTEMIS; PAIS, MARINA; CHAPARRO GARCÍA, ANGELA; SEGRETIN, M.E.; KAMOUN, SOPHIEN

Big Sky

Simposio; Keystone Symposia: Plant Immunity: Pathways and Translation; 2013

Keystone Symposia

Pathogens deploy effector proteins that modulate host processes and immunity enabling parasitic infection. In turn, plants have evolved R proteins to recognize these effectors, reflecting a coevolutionary arms race between plants and pathogens. Effector proteins (AVR) with avirulence activities are recognised by their cognate resistance protein (R) in the plant. Understanding the mechanism of recognition of AVR effectors by R immunoreceptors should prove helpful in managing and improving R-mediated resistance. The ascomycete Fusarium oxysporum f. sp. lycopersici (FOL), causal agent of wilt in tomato, is responsible for significant losses worldwide. Three races of FOL have been reported whose relationship with tomato cultivars is explained by the ‘gene-for-gene theory’ first described by Flor (1955). I, I2 and I3 are the R genes in tomato that correspond to FOL’s avirulence effector genes Avr1, Avr2 and Avr3, respectively. Our goal is to create synthetic R mutant genes with expanded pathogen recognition specificities, as a way to develop broad-spectrum solutions to plant pathogens sharing the same effector families. We are transferring previously characterized R gene mutations that confer expanded recognition to effectors of another important pathogen, the oomycete Phytophthora infestans, into I2, to assess whether these mutations also confer expanded activity in I2. Also, we plan to swap domains between orthologous R proteins with different specificities so as to identify regions conferring AVR recognition specificity. These results could lead to new insights into the molecular interactions underlying pathogen perception by plants, building up our knowledge in both basic and applied plant pathology.