Centro de Estudios Fotosintéticos y Bioquímicos (CEFOBI), CONICET-Universidad Nacional de Rosario, Suipacha 531, 2000, Rosario, Argentina.
Centro de Estudios Fotosintéticos y Bioquímicos (CEFOBI), CONICET-Universidad Nacional de Rosario, Suipacha 531, 2000, Rosario, Argentina.
Plant Sci. 2021 Mar;304:110808. doi: 10.1016/j.plantsci.2020.110808. Epub 2020 Dec 26.
Iron (Fe) is an essential micronutrient for plants and is present abundantly in the Earth's crust. However, Fe bioavailability in alkaline soils is low due to the decreased solubility of the ferric ions. Previously, we have demonstrated the relationship between the PAP/SAL1 retrograde signaling pathway, the activity of Strategy I Fe uptake genes (FIT, FRO2, IRT1), and ethylene signaling. In this work, we have characterized mutant lines that are deficient in this retrograde signaling pathway and their ability to grow in alkaline soils. This adverse growth condition caused less impact on mutant plants, which showed less reduced rosette area, and higher carotenoid, chlorophyll and Fe content than wild-type plants. Several genes involved in the biosynthesis and excretion of secondary metabolites derived from the phenylpropanoid pathway, which improve Fe uptake, were elevated in mutant plants. Finally, we observed an increase in excreted fluorescent phenolic compounds in mutant lines compared to wild-type plants. In this way, PAP/SAL1 mutants showed alterations in the biosynthesis of metabolites that mobilize Fe, which ultimately improved these plants ability to grow in alkaline soils. Results agree with the existence of a link between the PAP/SAL1 retrograde signaling pathway and the regulation of Fe deficiency responses in Arabidopsis.
铁（Fe）是植物必需的微量元素，在地壳中含量丰富。然而，由于高价铁离子的溶解度降低，碱性土壤中的铁生物利用度较低。以前，我们已经证明了 PAP/SAL1 逆行信号通路、策略 I 铁吸收基因（FIT、FRO2、IRT1）的活性与乙烯信号之间的关系。在这项工作中，我们对逆行信号通路缺陷的突变体系及其在碱性土壤中生长的能力进行了特征描述。这种不利的生长条件对突变体植物的影响较小，它们的莲座叶面积减少较少，类胡萝卜素、叶绿素和铁含量高于野生型植物。参与从苯丙烷途径衍生的次生代谢物生物合成和排泄的几个基因，这些基因可以提高铁的吸收，在突变体植物中升高。最后，我们观察到突变体与野生型植物相比，分泌的荧光酚类化合物增加。通过这种方式，PAP/SAL1 突变体显示出动员铁的代谢物生物合成的改变，这最终提高了这些植物在碱性土壤中生长的能力。结果与 PAP/SAL1 逆行信号通路与拟南芥铁缺乏反应调节之间存在联系的观点一致。
