Influence of cytokinins on the expression of phosphate starvation responsive genes in Arabidopsis
Influence of cytokinins on the expression of phosphate starvation responsive genes in Arabidopsis
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DOI：
10.1046/j.1365-313x.2000.00893.x
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发表时间：
2000-12-01
期刊：
影响因子：
7.2
通讯作者：
Paz-Ares, J
中科院分区：
文献类型：
--
作者：
Martín, AC;del Pozo, JC;Paz-Ares, J
在相同的条件下，根生长与芽生长的比率的增加是由细胞分裂素水平的降低引起的。然而，细胞分裂素在Pi饥饿的救援系统中的作用在很大程度上仍然未知。我们从拟南芥中分离了一个磷饥饿诱导的基因（PIPPS 1），并研究了细胞分裂素对其表达的影响。TPS 1属于TPSI 1/Mt4家族，该家族的成员由Pi饥饿特异性诱导，并且其RNA仅包含短的、非保守的开放阅读框。Pi剥夺诱导所有细胞的野生型植物中，而在pho 1突变体生长在富含Pi的土壤中，在根中的表达是由内皮层界定的BMPS 1的表达。这支持了这样的观点，即pho 1受损的木质部加载的Pi，长距离信号控制的Pi饥饿反应的行为通过负控制。外源性细胞分裂素抑制的表达，PIPS 1和其他Pi饥饿响应基因在响应Pi剥夺。然而，细胞分裂素没有抑制根毛的数量和长度的增加诱导的磷饥饿，响应依赖于当地的磷浓度，而不是整个植物磷的状态。我们的研究结果提出了细胞分裂素可能参与负调制的长距离，系统控制的Pi饥饿反应，这是依赖于整个植物的Pi状态。
The increase in the ratio of root growth to shoot growth that occurs in response to phosphate (Pi) deprivation is paralleled by a decrease in cytokinin levels under the same conditions. However, the role of cytokinin in the rescue system for Pi starvation remains largely unknown. We have isolated a gene from Arabidopsis thaliana (AtlPS1) that is induced by Pi starvation, and studied the effect of cytokinin on its expression in response to Pi deprivation. AtlPS1 belongs to the TPSI1/Mt4 family, the members of which are specifically induced by Pi starvation, and the RNAs of which contain only short, non-conserved open reading frames. Pi deprivation induces AtlPS1 expression in all cells of wild-type plants, whereas in the pho1 mutant grown on Pi-rich soils, AtlPS1 expression in the root was delimited by the endodermis. This supports the view that pho1 is impaired in xylem loading of Pi, and that long-distance signals controlling the Pi starvation responses act via negative control. Exogenous cytokinins repress the expression of AtlPS1 and other Pi starvation-responsive genes in response to Pi deprivation. However, cytokinins did not repress the increase in root-hair number and length induced by Pi starvation, a response dependent on local Pi concentration rather than on whole-plant Pi status. Our results raise the possibility that cytokinins may be involved in the negative modulation of long-distance, systemically controlled Pi starvation responses, which are dependent on whole-plant Pi status.