ARS | Publication request: Understanding Interactions between Phytopathogenic Phytophthora Effector IpiO and the Host Resistance Protein RB

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: March 10, 2009
Publication Date: August 9, 2009
Citation: Halterman, D.A. 2009. Understanding Interactions between Phytopathogenic Phytophthora Effector IpiO and the Host Resistance Protein RB [abstract]. XIV International Congress on Molecular Plant-Microbe Interactions.

Technical Abstract: Species of phytopathogenic Phytophthora are well known for their ability to cause disease on economically important crops, with almost 100 recognized species targeting close to 300 different hosts. The host resistance protein RB, isolated from wild potato, specifically recognizes the P. infestans IpiO effector to elicit resistance. Using P. infestans isolates collected worldwide, we have found that IpiO is universally present, explaining the broad-spectrum phenotype of RB. However, we have found that multiple IpiO variants exist within a given P. infestans isolate. Importantly, some IpiO variants are recognized by RB (IpiO1 and IpiO2) and some are not (IpiO4). We have determined that IpiO alleles not recognized by RB can be recognized by RB-like genes from other potato species. Most importantly, we have found that IpiO alleles are present in other phylogenetically distinct Phytophthora species. Therefore, RB may not only confer resistance to late blight of potato and tomato, but is potentially a source of resistance to other Phytophthora species on related or unrelated hosts. Further elucidation of the molecular events involved in IpiO recognition will be presented.