NDR1, a locus of Arabidopsis thaliana that is required for disease resistance to both a bacterial and a fungal pathogen.

Abstract

We have employed Arabidopsis thaliana as a model host plant to genetically dissect the molecular pathways leading to disease resistance. A. thaliana accession Col-0 is susceptible to the bacterial pathogen Pseudomonas syringae pv. tomato strain DC3000 but resistant in a race-specific manner to DC3000 carrying any one of the cloned avirulence genes avrB, avrRpml, avrRpt2, and avrPph3. Fast-neutron-mutagenized Col-0 M2 seed was screened to identify mutants susceptible to DC3000(avrB). Disease assays and analysis ofin planta bacterial growth identified one mutant, ndrl-l (nonrace-specific disease resistance), that was susceptible to DC3000 expressing any one of the four avirulence genes tested. Interestingly, a hypersensitive-like response was still induced by several of the strains. The ndrl-l mutation also rendered the plant susceptible to several avirulent isolates of the fungal pathogen Peronospora parasitica. Genetic analysis of ndrl-1 demonstrated that the mutation segregated as a single recessive locus; located on chromosome III. Characterization of the ndrl-1 mutation suggests that a common step exists in pathways of resistance to two unrelated pathogens.

The hypersensitive response and the induction of cell death in plants

“…These may or may not converge (Parker et al, 1996;Century et al, 1995;Peterha È nsel et al, 1997). The HR also results from a complex interplay of signals from both the plant and the pathogen.…”

“…Thus eds-1 defines a function upstream from a possible convergence of bacterial and fungal resistance gene signaling pathways. In contrast, the Arabidopsis ndr-1 mutant is impaired in resistance against both bacteria and Peronospora ( Figure 2B; Century et al, 1995). Ndr could thus represent a downsteam step in signaling, after the convergence of pathways specific to fungal and bacterial pathogens.…”

NDR1 Interaction with RIN4 Mediates the Differential Activation of Multiple Disease Resistance Pathways in Arabidopsis

“…NDR1 was first identified in a genetic screen aimed at identifying genetic loci required for disease resistance signaling in Arabidopsis in response to infection by P. syringae (Century et al, 1995(Century et al, , 1997. NDR1 is a plasma membrane, glycophosphatidyl-inositol (GPI)-anchored protein required for the activation of disease resistance signaling mediated by members of the largest class of disease resistance proteins in Arabidopsis (Coppinger et al, 2004).…”

Genetic Dissection of Acquired Resistance to Disease

“…By contrast, mutants defective in steps downstream of pathogen recognition may simultaneously lose resistance to severa1 pathogens, provided that the resistance mechanisms that act against these organisms utilize common signal transduction pathways. The latter phenotypic class is represented by the ndrl (nonrace-specific disease yesistance) mutant, which was found to be susceptible to Pseudomonas syringae pv tomato (Pst) strains containing any of four cloned avirulence genes, as well as to severa1 isolates of the downy mildew fungus Pevonospora parasitica (Century et al, 1995). The loss of resistance to these widely divergent pathogens suggests that the ndrl mutation identifies a common signal transduction pathway that mediates resistance against both fungal and bacterial pathogens.…”