Investigation of the Arabidopsis nonhost resistance mechanism against the soybean pathogen, Phytophthora sojae

Abstract

<p>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 <em>Arabidopsis thaliana PEN</em> (penetration deficient) genes, <em>PEN1, 2</em> and <em>3</em> have been shown to provide prehaustorial NHR against the barley pathogen <em>Blumeria graminis</em> f. sp. <em>hordei</em>. Arabidopsis <em>pen1-1</em> mutant is penetrated by the hemibiotrophic oomycete pathogen, <em>Phytophthora sojae</em> that causes root and stem rot disease in soybean. The <em> P. sojae</em> susceptible (<em>pss</em>) <em>1</em> mutant is infected by both <em>P. sojae</em> and the hemibiotrophic fungal pathogen, <em>Fusarium virguliforme</em> that causes sudden death syndrome in soybean. Thus, a common Arabidopsis NHR mechanism is functional against both hemibiotrophic oomycete and fungal pathogens of soybean. <em>PSS1</em> 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 <em>P. sojae</em> and <em>F. virguliforme</em>. My study established that nonhost resistance genes are ideal for engineering broad-spectrum disease resistance in crop plants.</p>