A high-throughput screen of cell-death-inducing factors in Nicotiana benthamiana identifies a novel MAPKK that mediates INF1-induced cell death signaling and non-host resistance to Pseudomonas cichorii.
A high-throughput overexpression screen of Nicotiana benthamiana cDNAs identified a gene for a mitogen-activated protein kinase kinase (MAPKK) as a potent inducer of the hypersensitive response (HR)-like cell death. NbMKK1 protein is localized to the nucleus, and the N-terminal putative MAPK docking site of NbMKK1 is required for its function as a cell-death inducer. NbMKK1-mediated leaf-cell death was compromised in leaves where NbSIPK expression was silenced by virus-induced gene silencing. A yeast two-hybrid assay showed that NbMKK1 and NbSIPK physically interact, suggesting that NbSIPK is one of the downstream targets of NbMKK1. Phytophthora infestans INF1 elicitor-mediated HR was delayed in NbMKK1-silenced plants, indicating that NbMKK1 is involved in this HR pathway. Furthermore, the resistance of N. benthamiana to a non-host pathogen Pseudomonas cichorii was compromised in NbMKK1-silenced plants. These results demonstrate that MAPK cascades involving NbMKK1 control non-host resistance including HR cell death.
Takahashi
Yoshihiro
Y
Iwate Biotechnology Research Center, 22-174-4, Narita, Kitakami, Iwate 024-0003, Japan.
Nasir
Khairun Hisam Bin
KH
Ito
Akiko
A
Kanzaki
Hiroyuki
H
Matsumura
Hideo
H
Saitoh
Hiromasa
H
Fujisawa
Shizuko
S
Kamoun
Sophien
S
Terauchi
Ryohei
R
D016923:Cell Death / Q000502:physiology*; D002467:Cell Nucleus / Q000378:metabolism; D015870:Gene Expression; D006861:Hydrogen Peroxide / Q000378:metabolism; D007113:Immunity, Innate / Q000502:physiology*; D020935:MAP Kinase Signaling System / Q000502:physiology; D020929:Mitogen-Activated Protein Kinase Kinases / Q000502:physiology*; D010935:Plant Diseases; D011549:Pseudomonas / Q000502:physiology*; D015398:Signal Transduction / Q000502:physiology*; D014026:Nicotiana
D006861:Hydrogen Peroxide; D020929:Mitogen-Activated Protein Kinase Kinases