Phosphate starvation responses are mediated by sugar signaling in Arabidopsis
Phosphate starvation responses are mediated by sugar signaling in Arabidopsis
复制标题
DOI：
10.1007/s00425-006-0408-8
复制
发表时间：
2007-03-01
期刊：
影响因子：
4.3
通讯作者：
Raghothama, Kashchandra G.
中科院分区：
文献类型：
--
作者：
Karthikeyan, Athikkattuvalasu S.;Varadarajan, Deepa K.;Raghothama, Kashchandra G.
磷酸盐(PI)是土壤中最难利用的植物养分之一。它与碳素的动态变化以及调节植物生长和发育的几个关键过程有关。PI水平调节大量基因的表达，包括那些涉及光合作用和碳代谢的基因。在此，我们证明了糖是PI饥饿反应所必需的，包括拟南芥根构型的改变和磷酸盐饥饿诱导(PSI)基因的表达。在PI限制条件下，活跃的光合作用或在培养基中添加糖是PSI基因表达所必需的。这些基因的表达不仅被蔗糖诱导，而且还被检测到，尽管水平降低，但与其他可代谢的糖。非代谢糖类似物不能诱导PSI基因的表达。虽然糖的输入似乎是在初始PI感应的下游，但它是PSI信号通路完成所必需的。己糖激酶信号突变体GIN2中PSI基因表达的改变表明己糖激酶依赖的信号转导参与了这一过程。这项研究为PSI信号转导中糖的需求提供了证据，并唤起了己糖激酶在PI反应机制某些组成部分中的作用。
Phosphate (Pi) is one of the least available plant nutrients in soils. It is associated with dynamic changes in carbon Xuxes and several crucial processes that regulate plant growth and development. Pi levels regulate the expression of large number of genes including those involved in photosynthesis and carbon metabolism. Herein we show that sugar is required for Pi starvation responses including changes in root architecture and expression of phosphate starvation induced (PSI) genes in Arabidopsis. Active photosynthesis or the supplementation of sugar in the medium was essential for the expression of PSI genes under Pi limiting conditions. Expression of these genes was not only induced by sucrose but also detected, albeit at reduced levels, with other metabolizable sugars. Non-metabolizable sugar analogs did not induce the expression of PSI genes. Although sugar input appears to be downstream of initial Pi sensing, it is absolutely required for the completion of the PSI signaling pathway. Altered expression of PSI genes in the hexokinase signaling mutant gin2 indicates that hexokinase-dependent signaling is involved in this process. The study provides evidence for requirement of sugars in PSI signaling and evokes a role for hexokinase in some components of Pi response mechanism.