|Chen, Yu -|
Submitted to: Potato Association of America Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: March 19, 2010
Publication Date: August 15, 2010
Citation: Halterman, D.A., Chen, Y. 2010. Competitive Interaction Between Phytophthora Infestans Effectors Leads to Increased Aggressiveness on Plants Containing Broad-spectrum Late Blight Resistance [abstract]. Potato Association of America Proceedings. Paper No. 25. Technical Abstract: The resistance (R) gene RB confers broad-spectrum resistance to potato late blight and belongs. The RB protein recognizes the presence of members of the Phytophthora infestans effector family IPI-O to elicit resistance. Most isolates of the pathogen contain IPI-O variants that are recognized by RB, explaining the broad-spectrum resistance phenotype of this gene. However, some isolates contain an IPI-O variant (IPI-O4) that is not recognized by RB. Isolates containing IPI-O4 are able to overcome resistance in RB-containing potato leaves to cause significantly more disease than isolates that do not contain IPI-O4, even when other IPI-O proteins are present. We have found that the presence of IPI-O4 blocks the ability of RB to recognize the presence of other IPI-O variants through direct interaction with the resistance protein, thereby preventing programmed cell death related to the resistance response. Molecular determinants of this interaction are being elucidated and we hope that this information will lead to the engineering or identification of improved late blight resistance genes.