title: Rpi-blb2-Mediated Hypersensitive Cell Death Caused by Phytophthora infestans AVRblb2 Requires SGT1, but not EDS1, NDR1, Salicylic Acid-, Jasmonic Acid-, or Ethylene-Mediated Signaling.
abstract: Potato Rpi-blb2 encodes a protein with a coiled-coil-nucleotide binding site and leucine-rich repeat (CC-NBS-LRR) motif that recognizes the Phytophthora infestans AVRblb2 effector and triggers hypersensitive cell death (HCD). To better understand the components required for Rpi-blb2-mediated HCD in plants, we used virus-induced gene silencing to repress candidate genes in Rpi-blb2-transgenic Nicotiana benthamiana plants and assayed the plants for AVRblb2 effector. Rpi-blb2 triggers HCD through NbSGT1-mediated pathways, but not NbEDS1- or NbNDR1-mediated pathways. In addition, the role of salicylic acid (SA), jasmonic acid (JA), and ethylene (ET) in Rpi-blb2-mediated HCD were analyzed by monitoring of the responses of NbICS1-, NbCOI1-, or NbEIN2-silenced or Rpi-blb2::NahG-transgenic plants. Rpi-blb2-mediated HCD in response to AVRblb2 was not associated with SA accumulation. Thus, SA affects Rpi-blb2-mediated resistance against P. infestans, but not Rpi-blb2-mediated HCD in response to AVRblb2. Additionally, JA and ET signaling were not required for Rpi-blb2-mediated HCD in N. benthamiana. Taken together, these findings suggest that NbSGT1 is a unique positive regulator of Rpi-blb2-mediated HCD in response to AVRblb2, but EDS1, NDR1, SA, JA, and ET are not required.
authors.affiliation: Department of Plant Science, Plant Genomics and Breeding Institute, Institute of Agricultural Biotechnology, Seoul National University, Seou1 151-742, Korea ; Korea Research Institute of Bioscience & Biotechnology, Daejeon 305-806, Korea.
authors.forename: Sang-Keun
authors.initials: SK
authors.lastname: Oh
authors.affiliation: Korea Research Institute of Bioscience & Biotechnology, Daejeon 305-806, Korea.
authors.forename: Suk-Yoon
authors.initials: SY
authors.lastname: Kwon
authors.affiliation: Department of Plant Science, Plant Genomics and Breeding Institute, Institute of Agricultural Biotechnology, Seoul National University, Seou1 151-742, Korea.
authors.forename: Doil
authors.initials: D
authors.lastname: Choi
keywords: AVRblb2 effector; EDS1; NDR1; Rpi-blb2; SGT1; hypersensitive cell death