Expression of iron-acquisition-related genes in iron-deficient rice is co-ordinately induced by partially conserved iron-deficiency-responsive elements
Expression of iron-acquisition-related genes in iron-deficient rice is co-ordinately induced by partially conserved iron-deficiency-responsive elements
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DOI：
10.1093/jxb/eri131
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发表时间：
2005-05-01
影响因子：
6.9
通讯作者：
Nishizawa, NK
中科院分区：
文献类型：
--
作者：
Kobayashi, T;Suzuki, M;Nishizawa, NK
水稻植株(Oryza sativa L.)利用被称为芥酸家族植物铁载体(MAS)的铁络合剂从根际获取铁。在缺铁条件下，MAS的合成和MA络合铁的摄取被强烈诱导。利用基因芯片技术从基因组水平分析水稻对缺铁胁迫的响应。将从缺铁或缺铁水稻根或叶片中提取的mRNA与含有8987个克隆的水稻杂交。观察到57个基因在根中的诱导比大于2.0，其中许多基因与铁吸收机制有关，包括蛋氨酸循环中每一个已识别或预测的步骤，以及蛋氨酸生物合成MA的过程。Northern分析证实，编码蛋氨酸循环每一步的基因在根中完全被缺铁诱导，在叶片中几乎完全被诱导。启动子搜索表明，缺铁诱导的铁吸收相关基因在其启动子区域具有与缺铁反应顺式作用元件IDE1和IDE2同源的序列，其速率高于缺铁未诱导的基因。这些结果表明，水稻铁获取相关基因在缺铁反应中受到保守机制的协同调控，其中IDE介导的调控起着重要作用。
Rice plants (Oryza sativa L.) utilize the iron chelators known as mugineic acid family phytosiderophores (MAs) to acquire iron from the rhizosphere. Synthesis of MAs and uptake of MA-chelated iron are strongly induced under conditions of iron deficiency. Microarray analysis was used to characterize the expression profile of rice in response to iron deficiency at the genomic level. mRNA extracted from iron-deficient or iron-sufficient rice roots or leaves was hybridized to a rice array containing 8987 cDNA clones. An induction ratio of greater than 2.0 in roots was observed for 57 genes, many of which are involved in iron-uptake mechanisms, including every identified or predicted step in the methionine cycle and the biosynthesis of MAs from methionine. Northern analysis confirmed that the expression of genes encoding every step in the methionine cycle is thoroughly induced by iron deficiency in roots, and almost thoroughly induced in leaves. A promoter search revealed that the iron-deficiency-induced genes related to iron uptake possessed sequences homologous to the iron-deficiency-responsive cis-acting elements IDE1 and IDE2 in their promoter regions, at a higher rate than that showing no induction under Fe deficiency. These results suggest that rice genes involved in iron acquisition are co-ordinately regulated by conserved mechanisms in response to iron deficiency, in which IDE-mediated regulation plays a significant role.