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）是植物必不可少的微量营养元素，地壳中大量存在。然而，由于铁离子的溶解度降低，因此在碱性土壤中铁的生物利用度较低。以前，我们已经证明了PAP / SAL1逆向信号通路与策略I Fe摄取基因（FIT，FRO2，IRT1）的活性之间的关系。）和乙烯信号。在这项工作中，我们已经表征了在这种逆行信号通路及其在碱性土壤中生长的能力不足的突变株。这种不利的生长条件对突变型植物的影响较小，与野生型植物相比，突变型植物的花环面积减少更少，类胡萝卜素，叶绿素和铁的含量更高。在突变植物中，一些涉及生物合成和排泄从苯丙烷途径衍生的次生代谢产物的基因提高了铁的吸收。最后，与野生型植物相比，我们观察到突变株中分泌的荧光酚类化合物增加。这样，PAP / SAL1突变体显示出动员铁的代谢产物的生物合成发生变化，从而最终提高了这些植物在碱性土壤中生长的能力。