Stem cell fate in hypoxic root apical meristems is influenced by phytoglobin expression

First author: Mohammed M Mira; Affiliations: University of Manitoba (曼尼托巴大学): Winnipeg, Canada

Corresponding author: Claudio Stasolla

Root survival to flooding-induced hypoxic stress (低氧胁迫) is dependent upon maintaining the functionality of the apical root meristem quiescent center (QC), a process that is governed by the basipetal (由顶部往基部) flow of auxin leading to the formation of an auxin maximum which is needed for the establishment of a highly oxidized environment specifying the QC niche. Perturbations in auxin flow and distribution along the root profile occurring during hypoxia can shift the redox state of the QC towards a more reduced environment leading to the activation of the QC, degradation of the meristem, and root abortion. The maize phytoglobin ZmPgb1.1 is involved in minimizing these damaging effects during hypoxia in processes that result in sustaining the PIN-mediated auxin maximum and an oxidized environment in the QC. The oxidized environment is accomplished by maintaining the activity of redox enzymes oxidizing ascorbate and glutathione. These events, compromised in QCs suppressing ZmPgb1.1, ensure the functionality of the QC and root meristems under conditions of low oxygen resulting in stable root performance.

植物根系能够在水淹诱导的低氧胁迫条件下存活依赖于根尖分生组织静止中心QC功能的维持，该过程是由植物顶部往根部的生长素流所介导的，通过形成一个生长素极大值点，建立一个高度氧化环境下特定的QC龛。缺氧条件下根中生长素流与分布的扰动会改变QC细胞的氧化还原状态，从而使得QC激活，分生组织瓦解，根发育缺陷。玉米球蛋白ZmPgb1.1基因会在低氧状态下保护植物免受伤害，维持PIN介导的生长素极大值点以及QC细胞的氧化状态。而QC细胞的氧化状态是通过维持能够氧化抗坏血酸盐和谷胱甘肽的氧化还原酶的活性来保证的。植物通过这种方式在低氧条件下保证QC和根分生组织的功能，从而保证根的正常发育。

通讯：Claudio Stasolla  (http://home.cc.umanitoba.ca/~stasolla/index.html)

研究方向：植物胚胎发育的生理和分子生物学研究；体外培养时火炬松细胞的木质化。

doi: https://doi.org/10.1093/jxb/erz410

Journal: Journal of Experimental Botany

Published date: September 21, 2019