Heat shock protein 70 is required for tabtoxinine-尾-lactam-induced cell death in Nicotiana benthamiana
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- 作者：Makoto Ito ; Yu Yamamoto ; Chul-Sa Kim ; Kouhei Ohnishi ; Yasufumi Hikichi ; Akinori Kiba
- 关键词：HR ; hypersensitive response ; Hsp ; heat shock protein ; MSX ; l-methionine sulfoximine ; PCR ; polymerase chain reaction ; PCD ; programmed cell death ; RT-PCR ; reverse transcription-polymerase chain reaction ; qRT-PCR ; quantitative real time polymerase chain reaction ; T尾L ; tabtoxinine-尾-lactam ; VIGS ; virus-induced gene silencing
- 刊名：Journal of Plant Physiology
- 出版年：15 January, 2014
- 年：2014
- 卷：171
- 期：2
- 页码：173-178
- 全文大小：1238 K
文摘
Tabtoxinine-尾-lactam (T尾L), a non-specific bacterial toxin, is produced by Pseudomonas syringae pv. tabaci, the causal agent of tobacco wildfire disease. T尾L causes death of plant cells through the inhibition of glutamine synthetase, which leads to an abnormal accumulation of ammonium ions and the characteristic necrotic wildfire lesions. To better understand the mechanisms involved in T尾L-induced cell death, we studied its regulation in Nicotiana benthamiana. T尾L-induced lesions, similar to those in controls, could be observed in SGT1-, RAR1- and Hsp90-silenced plants. In contrast, Hsp70-silenced plants showed suppression of lesion formation. Expression of hin1, a marker gene for the hypersensitive response (HR), which is a characteristic of programmed cell death in plants, was strongly induced in controls by T尾L treatment but only slightly in Hsp70-silenced plants. However, in these T尾L-treated Hsp70-silenced plants, the amount of ammonium ions was considerably increased. Furthermore, the silencing of Hsp70 also suppressed l-methionine sulfoximine-induced cell death and hin1 expression and caused the over-accumulation of ammonium ions. When inoculated directly with P. syringae pv. tabaci, Hsp70-silenced plants showed only reduced symptoms. Our results suggest that the T尾L-induced pathway to cell death in N. benthamiana is at least partially similar to HR response, and that Hsp70 might play an essential role in these events.