The transcription factor OsNAC4 is a key positive regulator of plant hypersensitive cell death

Abstract

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 þ -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.

New insights in the battle between wheat and Puccinia striiformis

“…In recent years, increasing evidence has implicated some NAC genes in plant defense response to pathogen infection and environmental stimuli, particularly the genes in the ATAF subfamily. Overexpression of OsNAC4 resulted in HR cell death, and in OsNAC4 knockdown lines, HR cell death was markedly decreased in response to avirulent bacterial strains (Acidovorax avenae N1141) [65] . In wheat, two novel NAC transcription factors TaNAC4 [66] and TaNAC8 [67] were isolated from a wheat-Pst cDNA library and both were upregulated upon infection by an avirulent Pst race, suggesting that they may be involved in wheat defense to Pst infection.…”

Overexpression of rice NAC transcription factor OsNAC58 on increased resistance to bacterial leaf blight

“…OsNAC19가 도열병 감염 시 전사활 성인자이고 Methyl Jasmonic acid(MeJA)-매개 신호과정에 관 여한다고 알려졌으며 (Lin et al 2007), 벼의 OsNAC5가 잎의 노화를 조절하는데 관여한다는 보고를 하였다 (Sperotto et al 2009). ONAC048 (OsNAC6), ONAC048 (OsNAC111), ONAC122 과 ONAC131 등 6개의 벼 NAC 유전자들이 도열병에 대한 병 방어 반응에 관여한다고 보고 하였으며 (Nakashima et al 2007;Sun et al 2013;Yokotani et al 2014), ONAC054 (RIM1)는 rice dwarf virus저항성에 부정적 영향을 주고 ONAC068 (OsNAC4)은 과민성 세포 죽음에 긍정적 조절 유전자로서 기 능을 한다고 보고했다 (Yoshii et al 2009;Kaneda et al 2009). 벼 에서 분리한 전사인자 OsNAC69-과발현 형질전환체가 벼흰 잎마름병 저항성을 가져온다는 보고를 하였으며 (Park SR et al 2011), 마이크로 RNA mi164와 연관된 OMTN NAC 전사인 자가 벼에서 가뭄 저항성을 음성적으로 조절한다는 보고도 있다 (Fang et al 2014).…”

Genetic Organization of thehrpGene Cluster inAcidovorax avenaeStrain N1141 and a Novel Effector Protein That Elicits Immune Responses in Rice (Oryza sativaL.)

“…This was dependent on de novo protein synthesis, accompanied by 180-bp nucleosomal DNA laddering and characteristic changes in cell morphology including plasma membrane shrinkage and nuclear condensation. [9][10][11] Induction of HR cell death indicates that both PTI and ETI are induced by interaction between the N1141 strain and rice cells. Since infection by the N1141 strain induced HR cell death, we postulated that the N1141 strain contains a specific effector protein that is injected into rice cells via T3SS.…”