College of Life Sciences, Northwest A&F University, Yangling, 712100 Shaanxi, China.
Plant Sci. 2012 May;187:59-68. doi: 10.1016/j.plantsci.2012.01.014. Epub 2012 Feb 8.
Sucrose induces the expression of miR398 and the production of miR398 is controlled by SQUAMOSA promoter binding protein-like7 (SPL7) transcription factor under copper deficiency in Arabidopsis thaliana. Little else, however, is known about the sucrose-regulated copper homeostasis in Arabidopsis. Here, we employed the microarray technology to screen for sucrose-responsive microRNAs (miRNAs), and identified several candidates using northern blotting. In addition to miR398, miR408, miR319, and miR160 are also responsive to sucrose. Furthermore, the induction of miR398 and miR408 by sucrose depends on the presence of SPL7. MiR398 and miR408 induction by high sucrose was eliminated by high copper. Meanwhile, high sucrose treatment strongly suppressed copper accumulation. Knock-down of SPL7 dramatically reduced copper accumulation in plants under low sucrose, but this effect was compromised in the presence of high levels of sucrose. Taken together, these results suggest a connection between sucrose signaling and copper accumulation in cells, and that sucrose-regulated copper accumulation is both SPL7-dependent and SPL7-independent in Arabidopsis.
蔗糖诱导 miR398 的表达，并且在拟南芥铜缺乏时，miR398 的产生受 SQUAMOSA 启动子结合蛋白样 7 (SPL7) 转录因子的控制。然而，关于拟南芥中蔗糖调节的铜稳态知之甚少。在这里，我们采用微阵列技术筛选蔗糖响应的 microRNAs (miRNAs)，并用 northern 印迹法鉴定了几个候选物。除了 miR398，miR408、miR319 和 miR160 也对蔗糖有反应。此外，蔗糖对 miR398 和 miR408 的诱导依赖于 SPL7 的存在。高浓度蔗糖诱导的 miR398 和 miR408 被高铜消除。同时，高浓度蔗糖处理强烈抑制铜积累。在低蔗糖下，SPL7 的敲低显著降低了植物中的铜积累，但在高浓度蔗糖存在下，这种效应受到损害。总之，这些结果表明细胞中蔗糖信号与铜积累之间存在联系，并且蔗糖调节的铜积累在拟南芥中既依赖于 SPL7 又不依赖于 SPL7。
