Cell death mechanism triggered by aluminium (Al) ion was investigated at root apex of tobacco (cultivar Bright Yellow) and in cultured tobacco cell line BY-2 derived from Bright Yellow, focusing on VPE genes (NtVPE1a, NtVPE1b, NtVPE2, NtVPE3). Cell death was detected as a loss of integrity of the plasma membrane by vital staining with fluorescein diacetate (in root apex) and Evans blue (in BY-2), respectively. At root apex, the upregulation of gene expression of VPE1a and VPE1b was observed significantly after 9 h of Al exposure in parallel with an enhancement of cell death, while the upregulation of VPE2 and VPE3 were observed later. Similarly, in BY-2 cells, the upregulation of VPE1a and VPE1b and the enhancement of cell death were synchronously observed after 3-h exposure to Al, while the upregulation of VPE2 and VPE3 occurred later. RNA interference (RNAi) lines of each of the VPEs were constructed in BY-2 cells. Comparative studies between wild-type and the RNAi lines indicated that both Al-enhanced VPE activity and Al-induced cell death were significantly suppressed in the RNAi lines of VPE1 (dual suppressor of VPE1a and VPE1b), but not in the RNAi lines of VPE2 and that of VPE3. Taken together, we conclude that the upregulation of VPE1 gene expression and following enhancement of VPE activity under Al stress cause cell death in actively growing or elongating cells of tobacco.

在烟草的根尖（品种亮黄）和来源于亮黄的培养烟草细胞系BY-2中，研究了铝（Al）离子触发的细胞死亡机制，重点研究了VPE基因（NtVPE1a，NtVPE1b，NtVPE2，NtVPE3）。通过分别用双乙酸荧光素（在根尖处）和伊文思蓝（在BY-2中）进行活体染色，检测到细胞死亡是质膜完整性的损失。在根尖处，铝暴露9 h后，显着观察到VPE1a和VPE1b基因表达上调，同时细胞死亡增加，而VPE2和VPE3上调后来被观察到。类似地，在BY-2细胞中，暴露于Al 3小时后，同时观察到VPE1a和VPE1b的上调和细胞死亡的增强，而VPE2和VPE3的上调则随后发生。在BY-2细胞中构建了每个VPE的RNA干扰（RNAi）系。野生型和RNAi品系之间的比较研究表明，在VPE1的RNAi品系（VPE1a和VPE1b的双重抑制剂）中，铝增强的VPE活性和Al诱导的细胞死亡均被显着抑制，而在VPE2的RNAi品系中却没有。和VPE3的。两者合计，我们得出结论，在Al胁迫下，VPE1基因表达的上调和VPE活性的增强会在活跃生长或伸长的烟草细胞中引起细胞死亡。