The transcription factor OsNAC4 is a key positive regulator of plant hypersensitive cell death.
The hypersensitive response (HR) is a common feature of plant immune responses and a type of programmed cell death. However, little is known about the induction mechanism of HR cell death. We report that overexpression of OsNAC4, which encodes a plant-specific transcription factor, leads to HR cell death accompanied by the loss of plasma membrane integrity, nuclear DNA fragmentation and typical morphological changes. In OsNAC4 knock-down lines, HR cell death is markedly decreased in response to avirulent bacterial strains. After induction by an avirulent pathogen recognition signal, OsNAC4 is translocated into the nucleus in a phosphorylation-dependent manner. A microarray analysis showed that the expression of 139 genes including OsHSP90 and IREN, encoding a Ca(2+)-dependent nuclease, were different between the OsNAC4 knock-down line and control line during HR cell death. During the induction of HR cell death, OsHSP90 is involved in the loss of plasma membrane integrity, whereas IREN causes nuclear DNA fragmentation. Overall, our results indicate that two important events occurring during HR cell death are regulated by independent pathways.
Kaneda
Takashi
T
Graduate School of Biological Sciences, Nara Institute of Science and Technology (NAIST), Takayama Ikoma, Nara, Japan.
Taga
Yuri
Y
Takai
Ryota
R
Iwano
Megumi
M
Matsui
Hiroyoshi
H
Takayama
Seiji
S
Isogai
Akira
A
Che
Fang-Sik
FS
D016923:Cell Death / Q000502:physiology*; D002462:Cell Membrane / Q000378:metabolism; D002467:Cell Nucleus / Q000378:metabolism; D018841:HSP90 Heat-Shock Proteins / Q000235:genetics / Q000378:metabolism; D012275:Oryza / Q000235:genetics / Q000378:metabolism; D010766:Phosphorylation; D010940:Plant Proteins / Q000378:metabolism*; D030821:Plants, Genetically Modified; D034622:RNA Interference; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*
D018841:HSP90 Heat-Shock Proteins; D010940:Plant Proteins; D014157:Transcription Factors