State Key Laboratory of Plant Physiology and Biochemistry, College of Life Sciences, Zhejiang University, Hangzhou, 310058, China.
Plant Cell Environ. 2014 Jul;37(7):1586-97. doi: 10.1111/pce.12258. Epub 2014 Mar 20.
Significant secretion of citrate from root apex of rice bean (Vigna umbellata) is delayed by several hours under aluminium (Al) stress. However, the molecular basis of regulation of VuMATE1, a gene encoding an Al-activated citrate transporter, remains unclear. In this study, we used suppression subtractive hybridization together with reverse northern blot analysis and qRT-PCR to identify genes with altered transcript levels in the root apex after treatment with low (5 μm) or high (25 μm) concentration of AlCl(3) for a short time (4 h). We found that in addition to VuMATE1, 393 genes showed an early response to Al. Among functionally annotated genes, those related to 'metabolism and energy', 'signal transduction and transcription' and 'transport' was predominantly up-regulated, whereas those associated with 'protein translation, processing and degradation' was predominantly down-regulated. Comparative analysis of transcriptional profiles highlighted candidate genes associated with citrate secretion and revealed several new aspects of the molecular processes underlying Al toxicity and tolerance. Based on the data, it is proposed that metabolic changes represent adaptive mechanisms to Al stress, whereas inhibition of both cell elongation and cell division underlies Al-induced root growth inhibition.
铝胁迫下，稻豆根尖的柠檬酸分泌要延迟数小时。然而，调控基因 VuMATE1（编码一种铝激活的柠檬酸转运蛋白）的分子机制尚不清楚。在这项研究中，我们采用抑制差减杂交技术，结合反转Northern 印迹分析和 qRT-PCR，在根尖经低（5 μM）、高（25 μM）浓度 AlCl3 短时间（4 h）处理后，鉴定出根尖中差异表达的基因。结果发现，除 VuMATE1 外，还有 393 个基因对 Al 表现出早期响应。在功能注释基因中，与“代谢和能量”、“信号转导和转录”和“运输”相关的基因主要上调，而与“蛋白质翻译、加工和降解”相关的基因主要下调。转录谱的比较分析突出了与柠檬酸分泌相关的候选基因，并揭示了铝毒性和耐受性的分子过程的几个新方面。基于这些数据，我们提出代谢变化是对铝胁迫的适应性机制，而细胞伸长和分裂的抑制是铝诱导的根生长抑制的基础。
