Iron(Fe)is an essential micronutrient for plant growth and development.Despite its importance,Fe uptake in alkaline soils is challenging for most plants because of its poor bioavailability.Plants have evolved two main...Iron(Fe)is an essential micronutrient for plant growth and development.Despite its importance,Fe uptake in alkaline soils is challenging for most plants because of its poor bioavailability.Plants have evolved two main strategies to acquire Fe.Grass species release phytosiderophores(PS)into the rhizosphere and take up Fe as Fe(III)-PS complexes via specific transporters(strategy II).Non-grass species,such as Arabidopsis thaliana,reduce Fe(III)to Fe(II)at the root surface and transport Fe(II)into the root via the high-affinity transporter IRT1(strategy I).Additionally,these species secrete catechol coumarins,such as fraxetin,into the rhizosphere to enhance Fe acquisition.Although the role of catechol coumarins in Fe reduction has been clearly demonstrated in acidic soils,their functions under alkaline conditions remain unclear.In this study,we demonstrate that,at circumneutral pH,the catechol coumarin fraxetin forms stable complexes with Fe(III).We also demonstrate that fraxetin significantly improves Fe nutrition,even in mutant plants lacking IRT1 and in the presence of the strong Fe(II)chelator ferrozine,suggesting that plants can bypass the conventional Fe(II)-dependent uptake pathway.These findings support the hypothesis that Fe-coumarin complexes are taken up by plant roots in a manner analogous to Fe(III)-PS complexes in grass species,thereby challenging the current paradigm for plant Fe uptake and suggesting a more unified and flexible model in which strategy I plants can utilize Fe(III)-chelating mechanisms similar to strategy II.展开更多
Plants face a constantly changing environment,requiring fine tuning of their growth and development.Plants have therefore developed numerous mechanisms to cope with environmental stress conditions.One striking exam-pl...Plants face a constantly changing environment,requiring fine tuning of their growth and development.Plants have therefore developed numerous mechanisms to cope with environmental stress conditions.One striking exam-ple is root response to water deficit.Upon drought(which causes osmotic stress to cells),plants can among other responses alter locally their root system architecture(hydropatterning)or orientate their root growth to optimize water uptake(hydrotropism).They can also modify their hydraulic properties,metabolism and development coordi-nately at the whole root and plant levels.Upstream of these developmental and physiological changes,plant roots must perceive and transduce signals for water availability.Here,we review current knowledge on plant osmotic per-ception and discuss how long distance signaling can play a role in signal integration,leading to the great phenotypic plasticity of roots and plant development.展开更多
基金supported by the French National Research Agency(ANR-10-INBS-04,“Investments for the Future”).Support for this work was provided to C.D.by the Agence Nationale de la Recherche(ANR17-CE20-0008 and ANR-22-CE20-0006)the National Research Institute for Agriculture,Food and the Environment(INRAE,BAP Department)+6 种基金supported by a fellowship from the Agence Nationale de la Recherche(ANR-17-CE20-0008)the BAP Department of INRAE.A.R.was supported by a fellowship from the Agence Nationale de la Recherche(ANR-22-CE20-0006)the BAP department of INRAE.M.L.was supported by the China Scholarship CouncilS.W.by a Marie Skłodowska-Curie Individual Fellowship in Horizon(2020)from the European Council(MSCA-IF-2020)funding from the Swiss National Fund for Research(nos.CRSII5_189996 and 310030_200793)the European Research Council Synergy Grant(no.951324-R2-TENSION)J.E.acknowledges a long-term EMBO fellowship(EMBO ALTF 989-2022).
文摘Iron(Fe)is an essential micronutrient for plant growth and development.Despite its importance,Fe uptake in alkaline soils is challenging for most plants because of its poor bioavailability.Plants have evolved two main strategies to acquire Fe.Grass species release phytosiderophores(PS)into the rhizosphere and take up Fe as Fe(III)-PS complexes via specific transporters(strategy II).Non-grass species,such as Arabidopsis thaliana,reduce Fe(III)to Fe(II)at the root surface and transport Fe(II)into the root via the high-affinity transporter IRT1(strategy I).Additionally,these species secrete catechol coumarins,such as fraxetin,into the rhizosphere to enhance Fe acquisition.Although the role of catechol coumarins in Fe reduction has been clearly demonstrated in acidic soils,their functions under alkaline conditions remain unclear.In this study,we demonstrate that,at circumneutral pH,the catechol coumarin fraxetin forms stable complexes with Fe(III).We also demonstrate that fraxetin significantly improves Fe nutrition,even in mutant plants lacking IRT1 and in the presence of the strong Fe(II)chelator ferrozine,suggesting that plants can bypass the conventional Fe(II)-dependent uptake pathway.These findings support the hypothesis that Fe-coumarin complexes are taken up by plant roots in a manner analogous to Fe(III)-PS complexes in grass species,thereby challenging the current paradigm for plant Fe uptake and suggesting a more unified and flexible model in which strategy I plants can utilize Fe(III)-chelating mechanisms similar to strategy II.
基金supported in part by the Agence Nationale de la Recherche(ANR-19-CE20-0008-01)the European Research Council(ERC)under the European Union’s Horizon 2020 research and innovation programme(Grant Agreement ERC-2017-ADG-788553).
文摘Plants face a constantly changing environment,requiring fine tuning of their growth and development.Plants have therefore developed numerous mechanisms to cope with environmental stress conditions.One striking exam-ple is root response to water deficit.Upon drought(which causes osmotic stress to cells),plants can among other responses alter locally their root system architecture(hydropatterning)or orientate their root growth to optimize water uptake(hydrotropism).They can also modify their hydraulic properties,metabolism and development coordi-nately at the whole root and plant levels.Upstream of these developmental and physiological changes,plant roots must perceive and transduce signals for water availability.Here,we review current knowledge on plant osmotic per-ception and discuss how long distance signaling can play a role in signal integration,leading to the great phenotypic plasticity of roots and plant development.
