Lucena Carlos, Romera Francisco J, Rojas Carmen L, García María J, Alcántara Esteban, Pérez-Vicente Rafael
Department of Agronomy, Edificio Celestino Mutis (C-4), Campus de Rabanales, University of Córdoba, 14014-Córdoba, Spain.
Department of Botany, Ecology and Plant Physiology, Edificio Celestino Mutis (C-4), Campus de Rabanales, University of Córdoba, 14014-Córdoba, Spain.
Funct Plant Biol. 2007 Dec;34(11):1002-1009. doi: 10.1071/FP07136.
Bicarbonate is considered one of the most important factors causing Fe chlorosis in Strategy I plants, mainly on calcareous soils. Most of its negative effects have been attributed to its capacity to buffer a high pH in soils, which can diminish both Fe solubility and root ferric reductase activity. Besides its pH-mediated effects, previous work has shown that bicarbonate can inhibit the induction of enhanced ferric reductase activity in Fe-deficient Strategy I plants. However, to date it is not known whether bicarbonate affects the upregulation of the ferric reductase gene and other genes involved in Fe acquisition. The objective of this work has been to study the effect of bicarbonate on the expression of several Fe acquisition genes in Arabidopsis (Arabidopsis thaliana L.), pea (Pisum sativum L.), tomato (Lycopersicon esculentum Mill.) and cucumber (Cucumis sativus L.) plants. Genes for ferric reductases AtFRO2, PsFRO1, LeFRO1 and CsFRO1; iron transporters AtITR1, PsRIT1, LeIRT1 and CsIRT1; H-ATPases CsHA1 and CsHA2; and transcription factors AtFIT and LeFER have been examined. The results showed that bicarbonate could induce Fe chlorosis by inhibiting the expression of the ferric reductase, the iron transporter and the H-ATPase genes, probably through alteration of the expression of Fe efficiency reactions (FER) (or FER-like) transcription factors.
碳酸氢根被认为是导致策略I植物缺铁黄化的最重要因素之一，主要发生在石灰性土壤中。其大部分负面影响归因于它缓冲土壤高pH值的能力，这会降低铁的溶解度和根系铁还原酶活性。除了其pH介导的效应外，先前的研究表明，碳酸氢根可以抑制缺铁策略I植物中铁还原酶活性增强的诱导。然而，迄今为止，尚不清楚碳酸氢根是否会影响铁还原酶基因和其他参与铁吸收的基因的上调。这项工作的目的是研究碳酸氢根对拟南芥（Arabidopsis thaliana L.）、豌豆（Pisum sativum L.）、番茄（Lycopersicon esculentum Mill.）和黄瓜（Cucumis sativus L.）植株中几个铁吸收基因表达的影响。研究了铁还原酶AtFRO2、PsFRO1、LeFRO1和CsFRO1；铁转运蛋白AtITR1、PsRIT1、LeIRT1和CsIRT1；H-ATP酶CsHA1和CsHA2；以及转录因子AtFIT和LeFER的基因。结果表明，碳酸氢根可能通过改变铁效率反应（FER）（或FER样）转录因子的表达，抑制铁还原酶、铁转运蛋白和H-ATP酶基因的表达，从而诱导缺铁黄化。
