Characterization of cell death induced by NbBPS1 silencing in Nicotiana benthamiana.
We previously showed that silencing of NbBPS1 encoding an endoplasmic reticulum (ER)-localized protein results in pleiotrophic developmental defects and cell death in Nicotiana benthamiana [Kang et al. (2008)]. In this study, we investigated the mechanism of the cell death caused by NbBPS1 silencing. Affected leaf cells exhibited morphological markers of programmed cell death (PCD) and accumulated excessive amounts of reactive oxygen species. NbBPS1 silencing caused dramatic induction of the ER stress marker genes BiP-like protein (BLP) genes, HSP70, and Bax Inhibitor-1. Furthermore, NbBPS1 deficiency led to relocalization of bZIP28 transcription factor from the ER membrane to the nucleus, similar to the bZIP28 relocalization during tunicamycin-induced ER stress. Abnormal accumulation of vesicles and increased autophagy activity were also observed in the affected leaf cells. These results suggest that inactivation of NbBPS1 function in the ER leads to ER stress, autophagy, and PCD activation in N. benthamiana.
Department of Systems Biology, Yonsei University, Seoul 120-749, Korea.
Yong Won
YW
Kang
Young
Y
Jeon
Hyun-Sook
HS
Pai
D000818:Animals; D001343:Autophagy; D016923:Cell Death / Q000187:drug effects / Q000235:genetics; D004721:Endoplasmic Reticulum / Q000235:genetics / Q000378:metabolism; D059865:Endoplasmic Reticulum Stress / Q000235:genetics; D018506:Gene Expression Regulation, Plant; D020868:Gene Silencing; D010940:Plant Proteins / Q000235:genetics* / Q000378:metabolism; D030821:Plants, Genetically Modified; D014026:Nicotiana / Q000166:cytology* / Q000235:genetics*; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism
D010940:Plant Proteins; D014157:Transcription Factors