van Hengel Arjon J, Roberts Keith
Department of Cell and Developmental Biology, John Innes Centre, Colney lane, Norwich, NR4 7UH, UK.
Plant J. 2002 Oct;32(1):105-13. doi: 10.1046/j.1365-313x.2002.01406.x.
The Arabidopsis thaliana mutant mur1 is affected in the biosynthesis of l-fucose and has less than 2% of the normal amounts of this sugar in the cell walls of its aerial parts. Although in roots the reduction of l-fucose is only 40%, this causes a decrease of about 50% in root cell elongation. Since arabinogalactan-proteins (AGPs) are known to play a role in plant cell expansion we studied the composition of mur1 root AGPs. Arabidopsis root AGPs were shown to contain l-fucose, which was reduced in level in mur1 AGPs. In wild-type plants, an l-fucose containing epitope is present in AGPs in the cell wall of differentiating root cells. Addition of eel lectin, which specifically recognizes this epitope, and not fucose in other wall polymers, can phenocopy mur1 roots. Several lines of evidence are presented to support the contention that l-fucose containing root AGPs are required for the full elongation of root cells.
拟南芥突变体mur1在L-岩藻糖的生物合成方面存在缺陷，其地上部分细胞壁中该糖的含量不到正常量的2%。尽管在根中L-岩藻糖的减少量仅为40%，但这导致根细胞伸长减少约50%。由于已知阿拉伯半乳聚糖蛋白（AGPs）在植物细胞扩展中起作用，我们研究了mur1根AGPs的组成。结果表明，拟南芥根AGPs含有L-岩藻糖，其在mur1 AGPs中的水平降低。在野生型植物中，含有L-岩藻糖的表位存在于分化根细胞细胞壁的AGPs中。添加能特异性识别该表位而非其他细胞壁聚合物中岩藻糖的鳗鱼凝集素，可模拟mur1根的表型。本文提供了几条证据来支持这一论点，即含有L-岩藻糖的根AGPs是根细胞充分伸长所必需的。
