Citrate secretion coupled with the modulation of soybean root tip under aluminum stress.: Up-regulation of transcription, translation, and threonine-oriented phosphorylation of plasma membrane H+ ATPase
Citrate secretion coupled with the modulation of soybean root tip under aluminum stress.: Up-regulation of transcription, translation, and threonine-oriented phosphorylation of plasma membrane H+ ATPase
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DOI：
10.1104/pp.104.058065
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发表时间：
2005-05-01
期刊：
影响因子：
7.4
通讯作者：
Matsumoto, H
中科院分区：
文献类型：
--
作者：
Shen, H;He, LF;Matsumoto, H
铝诱导的柠檬酸分泌是大豆抗铝的重要机制。然而，铝如何诱导柠檬酸分泌的机制仍不清楚。本文研究了质膜H ~+-ATPase对铝诱导的大豆根系柠檬酸分泌的调节作用。用全营养液培养的植物进行的实验表明，铝诱导的质膜H ~+-ATPase活性抑制柠檬酸的分泌。钒酸盐和fusicoccin分别是质膜H ~+-ATPase的抑制剂和激活剂，对铝诱导的柠檬酸分泌有抑制和刺激作用。抗铝品种质膜H+-ATPase活性高于铝敏感品种，与柠檬酸分泌量的增加相一致。这些结果表明，铝胁迫对柠檬酸分泌的影响是通过调节质膜H+-ATPase活性来实现的。通过对转质膜H ~+-ATPase基因拟南芥（Arabidopsis thaliana）的分析，进一步证实了铝诱导的柠檬酸分泌与质膜H ~+-ATPase活性之间的关系。当植物生长在Murashige和Skoog培养基含有30 μ M铝（9.1 μ M铝3+活性），转基因植物渗出更多的柠檬酸盐相比，野生型拟南芥。实时荧光定量RT-PCR和免疫检测分析结果表明，铝诱导的质膜H+-ATPase活性升高是通过转录和翻译调控实现的。此外，质膜H+-ATPase活性和表达量在抗铝品种高于铝敏感品种。铝以剂量和时间依赖的方式激活质膜H+-ATP酶的苏氨酸定向磷酸化。综上所述，我们的结果表明，质膜H+-ATPase活性的上调与柠檬酸从大豆根的分泌。
The aluminum (Al)-induced secretion of citrate has been regarded as an important mechanism for Al resistance in soybean ( Glycine max). However, the mechanism of how Al induces citrate secretion remains unclear. In this study, we investigated the regulatory role of plasma membrane H+-ATPase on the Al-induced secretion of citrate from soybean roots. Experiments performed with plants grown in full nutrient solution showed that Al-induced activity of plasma membrane H+-ATPase paralleled secretion of citrate. Vanadate and fusicoccin, an inhibitor and an activator, respectively, of plasma membrane H+-ATPase, exerted inhibitory and stimulatory effects on the Al-induced secretion of citrate. Higher activity of plasma membrane H+-ATPase coincided with more citrate secretion in Al-resistant than Al-sensitive soybean cultivars. These results suggested that the effects of Al stress on citrate secretion were mediated via modulation of the activity of plasma membrane H+-ATPase. The relationship between the Al-induced secretion of citrate and the activity of plasma membrane H+-ATPase was further demonstrated by analysis of plasma membrane H+-ATPase transgenic Arabidopsis (Arabidopsis thaliana). When plants were grown on Murashige and Skoog medium containing 30 mu M Al (9.1 mu M Al3+ activity), transgenic plants exuded more citrate compared with wild-type Arabidopsis. Results from real-time reverse transcription-PCR and immunodetection analysis indicated that the increase of plasma membrane H+-ATPase activity by Al is caused by transcriptional and translational regulation. Furthermore, plasma membrane H+-ATPase activity and expression were higher in an Al-resistant cultivar than in an Al-sensitive cultivar. Al activated the threonine-oriented phosphorylation of plasma membrane H+-ATPase in a dose- and time-dependent manner. Taken together, our results demonstrated that up-regulation of plasma membrane H+-ATPase activity was associated with the secretion of citrate from soybean roots.