Jiang Dexing, Wu Huihui, Cai Hui, Chen Guoxiang
Jiangsu Key Laboratory of Biodiversity and Biotechnology, College of Life Sciences, Nanjing Normal University, Nanjing, China.
Plant Cell Environ. 2022 Jun;45(6):1765-1778. doi: 10.1111/pce.14307. Epub 2022 Mar 23.
The root-apex transition zone (TZ), the major perception site for aluminium (Al) toxicity, is crucial for the Al-induced root-growth inhibition, while the mechanism underlying silicon-mediated alleviation of Al toxicity in the TZ is largely unknown. In this study, the role of silicon (Si) in alleviating Al-induced damage in the TZ and root-growth inhibition of rice was investigated. We found that Si had direct alleviative effect on Al toxicity as revealed by less root growth-inhibition, Al accumulation, and callose formation. Si reversed Al-induced decreases of the cell wall elongation and extensibility, and reduced Al-induced increments of cell wall polysaccharides in the TZ. The similar distribution patterns of Al and Si in the cell wall indicated that Si might detoxify Al by forming hydroxyaluminumsilicates in the apoplast of the root-apex TZ. Moreover, the wall-bound form of Si reduced Al binding sites, thereby reducing the capability of Al bound to the cell wall. These results suggest that Si-mediated cell wall modification in the TZ alleviates Al-induced root-growth inhibition in rice involving the promotion of cell wall extensibility and the decrease of Al accumulation in the cell wall.
根-根尖过渡区（TZ）是铝（Al）毒性的主要感知部位，对铝诱导的根生长抑制至关重要，而硅介导减轻过渡区铝毒性的潜在机制在很大程度上尚不清楚。在本研究中，研究了硅（Si）在减轻水稻过渡区铝诱导的损伤和根生长抑制中的作用。我们发现，硅对铝毒性具有直接缓解作用，表现为根生长抑制、铝积累和胼胝质形成减少。硅逆转了铝诱导的细胞壁伸长和伸展性降低，并减少了过渡区铝诱导的细胞壁多糖增加。铝和硅在细胞壁中的相似分布模式表明，硅可能通过在根-根尖过渡区的质外体中形成羟基铝硅酸盐来解毒铝。此外，细胞壁结合形式的硅减少了铝结合位点，从而降低了铝与细胞壁结合的能力。这些结果表明，硅介导的过渡区细胞壁修饰减轻了铝诱导的水稻根生长抑制，这涉及促进细胞壁伸展性和减少细胞壁中铝的积累。
