Submitted to: Potato Association of America Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: March 13, 2009
Publication Date: August 1, 2009
Citation: Halterman, D.A. 2009. Elucidating the Molecular Determinants of Broad-Spectrum Late Blight Resistance [abstract]. Potato Association of America Proceedings. p. 32. Technical Abstract: The Solanum bulbocastanum-derived gene RB (Rpi-blb1) confers resistance to multiple isolates of Phytophthora infestans in various potato backgrounds. RB specifically recognizes the P.infestans IpiO effector to elicit resistance, presumably within the potato cell cytoplasm. Recognition of IpiO by RB leads to increased resistance, with only minor disease symptoms observed on inoculated plants. 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 and that some IpiO variants are recognized by RB and others are not. The presence or absence of certain IpiO variants in P. infestans isolates can lead to virulence changes, even in the presence of RB. In order to identify additional sources of resistance, we are using a transient expression assay in Nicotiana benthamiana to test the outcome of interactions between IpiO genes and RB-like genes from other wild potato species. This talk will include recent research data and discussion of the long-term potential for incorporating broad-spectrum late blight resistance into cultivated varieties.