Departamento de Biodiversidad y Biología Experimental, Facultad de Ciencias Exactas y Naturales & Instituto de Biodiversidad, Biología Experimental y Aplicada, Universidad de Buenos Aires and Consejo Nacional de Investigaciones Científicas y Técnicas, C1428EGA, Buenos Aires, Argentina.
Departamento de Microbiología del Suelo y Sistemas Simbióticos, Estación Experimental del Zaidín (EEZ-CSIC), Profesor Albareda 1, 18008, Granada, Spain.
Plant Sci. 2021 May;306:110873. doi: 10.1016/j.plantsci.2021.110873. Epub 2021 Mar 6.
Soil salinity reduces root hydraulic conductivity (L) of several plant species. However, how cellular signaling and root hydraulic properties are linked in plants that can cope with water restriction remains unclear. In this work, we exposed the halotolerant species red beet (Beta vulgaris) to increasing concentrations of NaCl to determine the components that might be critical to sustaining the capacity to adjust root hydraulics. Our strategy was to use both hydraulic and cellular approaches in hydroponically grown seedlings during the first osmotic phase of salt stress. Interestingly, L presented a bimodal profile response apart from the magnitude of the imposed salt stress. As well as L, the PIP2-aquaporin profile follows an unphosphorylated/phosphorylated pattern when increasing NaCl concentration while PIP1 aquaporins remain constant. L also shows high sensitivity to cycloheximide. In low NaCl concentrations, L was high and 70 % of its capacity could be attributed to the CHX-inhibited cell-to-cell pathway. More interestingly, roots can maintain a constant spontaneous exudated flow that is independent of the applied NaCl concentration. In conclusion, Beta vulgaris root hydraulic adjustment completely lies in a dominant cell-to-cell pathway that contributes to satisfying plant water demands.
土壤盐度会降低几种植物的根水力传导率（L）。然而，对于能够耐受水分限制的植物，细胞信号转导和根水力特性是如何联系的仍不清楚。在这项工作中，我们将耐盐物种红甜菜（Beta vulgaris）暴露于不断增加的 NaCl 浓度下，以确定维持根水力调节能力可能至关重要的成分。我们的策略是在盐胁迫的第一个渗透阶段，使用水培幼苗中的水力和细胞方法。有趣的是，除了施加的盐胁迫的幅度外，L 呈现出双峰的响应模式。随着 NaCl 浓度的增加，PIP2-水通道蛋白的模式与非磷酸化/磷酸化模式一致，而 PIP1 水通道蛋白保持不变。L 对环己酰亚胺也表现出高灵敏度。在低 NaCl 浓度下，L 很高，其 70%的能力可以归因于 CHX 抑制的细胞间途径。更有趣的是，根可以维持一个恒定的自发渗出流量，与施加的 NaCl 浓度无关。总之，Beta vulgaris 根水力调节完全依赖于一种主要的细胞间途径，该途径有助于满足植物的水分需求。
