Membrane lipid alteration during phosphate starvation is regulated by phosphate signaling and auxin/cytokinin cross-talk
Membrane lipid alteration during phosphate starvation is regulated by phosphate signaling and auxin/cytokinin cross-talk
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DOI：
10.1111/j.1365-313x.2006.02778.x
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发表时间：
2006-07-01
期刊：
影响因子：
7.2
通讯作者：
Ohta, Hiroyuki
中科院分区：
文献类型：
--
作者：
Kobayashi, Koichi;Masuda, Tatsuru;Ohta, Hiroyuki
在植物磷（Pi）饥饿期间，膜磷脂含量减少伴随着非磷糖脂的增加。虽然一些研究表明，植物激素参与各种生理变化后，磷饥饿，磷饥饿诱导的膜脂变化的调节仍然是未知的。以前，我们报道了响应B型单半乳糖基二酰基甘油合酶基因（atMGD 2和atMGD 3）的Pi饥饿，并建议这些基因在半乳糖脂积累在Pi饥饿的作用。我们现在报告我们的调查的监管机制的atMGD 2/3和膜脂组成的变化，以Pi饥饿的反应。外源生长素激活atMGD 2/3表达在磷饥饿期间，而他们的表达被抑制细胞分裂素处理的根。此外，生长素抑制剂和axr 4 aux 1双突变的生长素信号损害增加atMGD 2/3表达在磷饥饿，表明生长素是必需的atMGD 2/3激活。事实上，激素的影响，在磷饥饿期间也观察到膜脂组成的变化方面，表明生长素和细胞分裂素确实参与了磷饥饿期间膜脂的动态变化。亚磷酸盐在植物中是不能代谢的;然而，当我们向Pi饥饿的植物提供亚磷酸盐时，相对于atMGD 2/3表达和膜脂质的变化，Pi饥饿反应消失。这些结果表明，所观察到的全球变化，在植物膜在磷饥饿不是由磷饥饿引起的植物细胞损伤，而是严格的Pi信号和生长素/细胞分裂素串扰调节。
During phosphate (Pi) starvation in plants, membrane phospholipid content decreases concomitantly with an increase in non-phosphorus glycolipids. Although several studies have indicated the involvement of phytohormones in various physiological changes upon Pi starvation, the regulation of Pi-starvation induced membrane lipid alteration remains unknown. Previously, we reported the response of type B monogalactosyl diacylglycerol synthase genes (atMGD2 and atMGD3) to Pi starvation, and suggested a role for these genes in galactolipid accumulation during Pi starvation. We now report our investigation of the regulatory mechanism for the response of atMGD2/3 and changes in membrane lipid composition to Pi starvation. Exogenous auxin activated atMGD2/3 expression during Pi starvation, whereas their expression was repressed by cytokinin treatment in the root. Moreover, auxin inhibitors and the axr4 aux1 double mutation in auxin signaling impaired the increase of atMGD2/3 expression during Pi starvation, showing that auxin is required for atMGD2/3 activation. The fact that hormonal effects during Pi starvation were also observed with regard to changes in membrane lipid composition demonstrates that both auxin and cytokinin are indeed involved in the dynamic changes in membrane lipids during Pi starvation. Phosphite is not metabolically available in plants; however, when we supplied phosphite to Pi-starved plants, the Pi-starvation response disappeared with respect to both atMGD2/3 expression and changes in membrane lipids. These results indicate that the observed global change in plant membranes during Pi starvation is not caused by Pi-starvation induced damage in plant cells but rather is strictly regulated by Pi signaling and auxin/cytokinin cross-talk.