PDF(Pubmed)
Abstract：
The cellulose-enriched tertiary cell walls present in many plant fibers have specific composition, architecture, machinery of formation, and function. To better understand the mechanisms underlying their mode of action and to reveal the peculiarities of fibers from different plant species, it is necessary to more deeply characterize the major components. Next to overwhelming cellulose, rhamnogalacturonan I (RG-I) is considered to be the key polymer of the tertiary cell wall; however, it has been isolated and biochemically characterized in very few plant species. Here, we add RG-I to the list from the phloem fibers of the Phaseolus vulgaris stem that was isolated and analyzed by nuclear magnetic resonance (NMR), dynamic light scattering, and immunolabeling, both within tissue and as an isolated polymer. Additionally, fibers with tertiary cell walls from nine species of dicotyledonous plants from the orders Malphigiales, Fabales, and Rosales were labeled with RG-I-related antibodies to check the presence of the polymer and compare the in situ presentation of its backbone and side chains. The obtained results confirm that RG-I is an obligatory polymer of the tertiary cell wall. However, there are differences in the structure of this polymer from various plant sources, and these peculiarities may be taxonomically related.
摘要：
许多植物纤维中存在的富含纤维素的三级细胞壁具有特定的组成，architecture,机器的形成，和功能。为了更好地了解其作用方式的潜在机制，并揭示来自不同植物物种的纤维的特殊性，有必要更深入地描述主要成分。除了压倒性的纤维素，鼠李糖半乳糖醛酸I（RG-I）被认为是三级细胞壁的关键聚合物；然而，它已被分离并在极少数植物物种中进行了生化表征。这里,我们将RG-I添加到通过核磁共振（NMR）分离和分析的菜豆茎的韧皮纤维列表中，动态光散射,和免疫标记，在组织内和作为分离的聚合物。此外,具有来自Malphigiales目的九种双子叶植物的三级细胞壁的纤维，Fabales,和Rosales用RG-I相关抗体标记以检查聚合物的存在并比较其主链和侧链的原位呈递。获得的结果证实RG-I是三级细胞壁的强制性聚合物。然而,来自各种植物来源的这种聚合物的结构存在差异，这些特性可能在分类上相关。
