Investigation of the Arabidopsis nonhost resistance mechanism against the soybean pathogen, Phytophthora sojae
Nonhost resistance (NHR) provides immunity to all members of a plant species against all isolates of a microorganism that is pathogenic to other plant species. Three Arabidopsis thaliana PEN (penetration deficient) genes, PEN1, 2 and 3 have been shown to provide prehaustorial NHR against the barley pathogen Blumeria graminis f. sp. hordei. Arabidopsis pen1-1 mutant is penetrated by the hemibiotrophic oomycete pathogen, Phytophthora sojae that causes root and stem rot disease in soybean. The P. sojae susceptible (pss) 1 mutant is infected by both P. sojae and the hemibiotrophic fungal pathogen, Fusarium virguliforme that causes sudden death syndrome in soybean. Thus, a common Arabidopsis NHR mechanism is functional against both hemibiotrophic oomycete and fungal pathogens of soybean. PSS1 encodes a glycine-rich protein (GRP), named GRP1, with no known function. Transformation of the soybean cultivar Williams 82 with AtGRP1 conferred enhanced resistance to both P. sojae and F. virguliforme. My study established that nonhost resistance genes are ideal for engineering broad-spectrum disease resistance in crop plants.