State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing, 210008, China.
State Key Laboratory of Plant Physiology and Biochemistry, College of Life Sciences, Zhejiang University, Hangzhou, 310058, China.
Plant Cell Environ. 2017 Sep;40(9):1916-1925. doi: 10.1111/pce.12999. Epub 2017 Jul 21.
Glucuronoxylan (GX), an important component of hemicellulose in the cell wall, appears to affect aluminium (Al) sensitivity in plants. To investigate the role of GX in cell-wall-localized xylan, we examined the Arabidopsis thaliana parvus mutant in detail. This mutant lacks α-D-glucuronic acid (GlcA) side chains in GX and has greater resistance to Al stress than wild-type (WT) plants. The parvus mutant accumulated lower levels of Al in its roots and cell walls than WT despite having cell wall pectin content and pectin methylesterase (PME) activity similar to those of WT. Our results suggest that the altered properties of hemicellulose in the mutant contribute to its decreased Al accumulation. Although we observed almost no differences in hemicellulose content between parvus and WT under control conditions, less Al was retained in parvus hemicellulose than in WT. This observation is consistent with the finding that GlcA substitutions in WT GX, but not mutant GX, were increased under Al stress. Taken together, these results suggest that the modulation of GlcA levels in GX affects Al resistance by influencing the Al binding capacity of the root cell wall in Arabidopsis.
木葡聚糖（GX）是细胞壁半纤维素的重要组成部分，似乎会影响植物对铝（Al）的敏感性。为了研究 GX 在细胞壁定位木聚糖中的作用，我们详细研究了拟南芥 parvus 突变体。该突变体缺乏 GX 中的α-D-葡萄糖醛酸（GlcA）侧链，对 Al 胁迫的抗性强于野生型（WT）植物。尽管突变体的细胞壁果胶含量和果胶甲酯酶（PME）活性与 WT 相似，但突变体的根和细胞壁中积累的 Al 水平低于 WT。我们的研究结果表明，突变体中半纤维素的特性改变导致其 Al 积累减少。尽管在对照条件下，我们观察到 parvus 和 WT 之间的半纤维素含量几乎没有差异，但突变体半纤维素中保留的 Al 比 WT 少。这一观察结果与以下发现一致：在 Al 胁迫下，WT GX 中的 GlcA 取代增加，但突变体 GX 中没有增加。总之，这些结果表明，通过影响拟南芥根细胞壁的 Al 结合能力，调节 GX 中的 GlcA 水平会影响 Al 抗性。
