BPMP, Univ Montpellier, CNRS, INRAE, Institut Agro, 34060, Montpellier, France.
Excellence Unit AGRIENVIRONMENT, CIALE, University of Salamanca, 37185, Salamanca, Spain.
New Phytol. 2021 Dec;232(6):2295-2307. doi: 10.1111/nph.17765. Epub 2021 Oct 21.
The formation of Casparian strips (CS) and the deposition of suberin at the endodermis of plant roots are thought to limit the apoplastic transport of water and ions. We investigated the specific role of each of these apoplastic barriers in the control of hydro-mineral transport by roots and the consequences on shoot growth. A collection of Arabidopsis thaliana mutants defective in suberin deposition and/or CS development was characterized under standard conditions using a hydroponic system and the Phenopsis platform. Mutants altered in suberin deposition had enhanced root hydraulic conductivity, indicating a restrictive role for this compound in water transport. In contrast, defective CS directly increased solute leakage and indirectly reduced root hydraulic conductivity. Defective CS also led to a reduction in rosette growth, which was partly dependent on the hydro-mineral status of the plant. Ectopic suberin was shown to partially compensate for defective CS phenotypes. Altogether, our work shows that the functionality of the root apoplastic diffusion barriers greatly influences the plant physiology, and that their integrity is tightly surveyed.
植物根内皮层中 Casparian 带的形成和角质层的沉积被认为限制了质外体中水分和离子的运输。我们研究了这两种质外体屏障在根系水力和矿质运输调控中的具体作用，以及它们对地上部分生长的影响。使用水培系统和 Phenopsis 平台，我们对拟南芥突变体中角质层沉积和/或 Casparian 带发育缺陷的特定作用进行了标准条件下的特征描述。角质层沉积缺陷的突变体具有增强的根水力传导性，表明该化合物在水分运输中具有限制作用。相比之下，功能缺陷的 Casparian 带直接增加溶质渗漏，并间接降低根水力传导性。功能缺陷的 Casparian 带还导致莲座生长减少，这部分取决于植物的水矿质状况。异位角质层被证明可以部分补偿 Casparian 带缺陷表型。总的来说，我们的工作表明，根质外体扩散屏障的功能极大地影响了植物生理学，并且它们的完整性受到严格监测。
