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Title: Discovering the next generation of late blight resistance genes – can we battle Phytophthora infestans evolution

Author
item Halterman, Dennis
item CHEN, YU - University Of Wisconsin
item SANCHEZ-PEREZ, AMILCAR - University Of Wisconsin

Submitted to: American Phytopathological Society Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: 3/17/2014
Publication Date: 8/9/2014
Citation: Halterman, D.A., Chen, Y., Sanchez-Perez, A. 2014. Discovering the next generation of late blight resistance genes – can we battle Phytophthora infestans evolution [abstract]. American Phytopathological Society Abstracts. Paper No. 582-P.

Interpretive Summary:

Technical Abstract: Potato late blight, caused by the oomycete pathogen Phytophthora infestans, is one of the most destructive plant diseases. RB from Solanum bulbocastanum encodes a CC-NB-LRR (CNL) protein that confers partial resistance to most P. infestans isolates through its recognition of the corresponding pathogen effector family IPI-O. While the majority of IPI-O proteins are recognized by RB to elicit host resistance (e.g. IPI-O1, IPI-O2), some family members are able to elude detection and block recognition of IPI-O1 (e.g. IPI-O4), leading to inactivation of RB-mediated programmed cell death. Our previous results suggested that in the absence of IPI-O, RB remains in a resting state. A conformational change occurs upon recognition of IPI-O1, which leads to an activated protein. However, when IPI-O4 is present, this effector interacts directly with the CC domain, thus suppressing RB activation. In this present study, RBCC-like fragments from wild potato species (CCwild) were sequenced and tested for intermolecular interactions with IPI-O and other RB CC domains in yeast. Our analysis identified two amino acids within the CC domain that determine CC domain self-association. Hybrid RB constructs (RBblb with the CC domain replaced by CCwild) were made to test IPI-O recognition in Nicotiana benthamiana. The goal of this study is to identify naturally occurring or engineered variants of RB that can recognize a broader spectrum of IPI-O effectors or can resist suppression by IPI-O4.