Putoczki Tracy L, Pettolino Filomena, Griffin Michael D W, Möller Ralf, Gerrard Juliet A, Bacic Antony, Jackson Sandra L
School of Biological Sciences, University of Canterbury, Private Bag 4800 Christchurch, New Zealand.
Planta. 2007 Oct;226(5):1131-42. doi: 10.1007/s00425-007-0559-2. Epub 2007 Jun 14.
A synthetic phenylglycoside (beta-GlcY) that interacts specifically with arabinogalactan-proteins (AGPs), a class of plant cell surface proteoglycans, has been used to study the spatial distribution of AGPs in the xylem tissue of radiata pine. These studies demonstrated that AGPs were located in the compound middle lamella (CML) of the newly developed tracheid. Abundant, low salt extractable AGPs were purified from xylem tissue. Monosaccharide analysis showed that arabinose and galactose were the main sugars present. Linkage analysis showed that most of the arabinose was in the furanose form, at the terminal and 5-linked positions, and the majority of the galactose was in the pyranose form at the terminal 3-, 6- and 3,6-linked positions; a linkage composition typical of AGPs. The AGPs had an abundance of characteristic amino acid residues including alanine, hydroxyproline, proline, and serine. Separation of the AGPs using reversed-phase high performance liquid chromatography showed that one main fraction was eluted, which tested positive for AGPs by dot-blot analysis using anti-AGP monoclonal antibodies. Sedimentation equilibrium analysis showed that this main fraction contained a 226 kDa species. We have examined the function of AGPs in tracheid differentiation using an established radiata pine callus culture system grown on media containing beta-GlcY. The effect of beta-GlcY on the cultures was to reduce the overall tracheid differentiation rate in a concentration dependent manner, ultimately resulting in cell death. These studies provide further evidence that AGPs play an important role in tracheid differentiation, and thus may be an important biological target for improving wood quality.
一种与阿拉伯半乳聚糖蛋白（AGP，一类植物细胞表面蛋白聚糖）特异性相互作用的合成苯基糖苷（β-GlcY）已被用于研究辐射松木质部组织中AGP的空间分布。这些研究表明，AGP位于新形成的管胞的复合中层（CML）中。从木质部组织中纯化出了大量、低盐可提取的AGP。单糖分析表明，阿拉伯糖和半乳糖是主要存在的糖类。连接分析表明，大多数阿拉伯糖以呋喃糖形式存在于末端和5-连接位置，而大多数半乳糖以吡喃糖形式存在于末端3-、6-和3,6-连接位置；这是AGP典型的连接组成。这些AGP含有大量特征性氨基酸残基，包括丙氨酸、羟脯氨酸、脯氨酸和丝氨酸。使用反相高效液相色谱法分离AGP，结果显示洗脱了一个主要组分，通过使用抗AGP单克隆抗体的斑点印迹分析，该组分对AGP呈阳性反应。沉降平衡分析表明，这个主要组分包含一个226 kDa的物质。我们使用在含有β-GlcY的培养基上生长的成熟辐射松愈伤组织培养系统，研究了AGP在管胞分化中的功能。β-GlcY对培养物的影响是浓度依赖性地降低整体管胞分化率，最终导致细胞死亡。这些研究提供了进一步的证据，表明AGP在管胞分化中起重要作用，因此可能是改善木材质量的一个重要生物学靶点。
