McCartney Lesley, Steele-King Clare G, Jordan Emillie, Knox J Paul
Centre for Plant Sciences, University of Leeds, Leeds LS2 9JT, UK.
Plant J. 2003 Feb;33(3):447-54. doi: 10.1046/j.1365-313x.2003.01640.x.
Here we demonstrate that the pectic rhamnogalacturonan-I-associated LM5 (1-->4)-beta-d-galactan epitope occurs in a restricted manner at the root surface of intact Arabidopsis seedlings. The root surface occurrence of (1-->4)-beta-d-galactan marks the transition zone at or near the onset of rapid cell elongation and the epitope is similarly restricted in occurrence in epidermal, cortical and endodermal cell walls. The extent of surface (1-->4)-beta-d-galactan occurrence is reduced in response to genetic mutations (stp-1, ctr-1) and hormone applications that reduce root cell elongation. In contrast, the application of the arabinogalactan-protein (AGP) binding beta-glucosyl Yariv reagent (betaGlcY) that disrupts cell elongation results in the persistence of (1-->4)-beta-d-galactan at the root surface and in epidermal, cortical and endodermal cell walls. This latter observation indicates that modulation of pectic (1-->4)-beta-d-galactan may be an event downstream of AGP function during cell expansion in the Arabidopsis seedling root.
在此我们证明，与果胶鼠李半乳糖醛酸聚糖-I相关的LM5（1→4）-β-D-半乳聚糖表位以一种受限的方式出现在完整拟南芥幼苗的根表面。（1→4）-β-D-半乳聚糖在根表面的出现标志着快速细胞伸长开始时或其附近的过渡区，并且该表位在表皮、皮层和内皮层细胞壁中的出现同样受到限制。响应于减少根细胞伸长的基因突变（stp-1、ctr-1）和激素处理，表面（1→4）-β-D-半乳聚糖的出现程度降低。相反，应用破坏细胞伸长的阿拉伯半乳聚糖蛋白（AGP）结合β-葡萄糖基Yariv试剂（βGlcY）会导致（1→4）-β-D-半乳聚糖在根表面以及表皮、皮层和内皮层细胞壁中持续存在。后一观察结果表明，在拟南芥幼苗根的细胞扩展过程中，果胶（1→4）-β-D-半乳聚糖的调节可能是AGP功能下游的一个事件。
