The structure and biochemistry of charophycean cell walls:: I.: Pectins of Penium margaritaceum
The structure and biochemistry of charophycean cell walls:: I.: Pectins of Penium margaritaceum
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DOI：
10.1007/s00709-006-0197-8
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发表时间：
2007-03-01
期刊：
影响因子：
2.9
通讯作者：
Gretz, M. R.
中科院分区：
文献类型：
--
作者：
Domozych, D. S.;Serfis, A.;Gretz, M. R.
植物细胞壁对于植物的正常生长、发育和与环境的相互作用是必不可少的。人们普遍认为，陆地植物起源于与轮藻(即链藻门)类似的水生祖先，研究这一过渡过程中的壁面进化有助于深入了解壁面成分的结构与功能关系。在这篇文章中，我们通过研究果胶聚合物结合到模式生物-珍珠霉的细胞壁-一种简单的单细胞结合体来探索细胞壁的进化史。这种生物只产生由三个纤维层或纤维层组成的初生壁，最外层终止于明显的钙化突起。用反式-1，2-二氨基环己烷-N，N，N‘，N’-四乙酸提取分离的细胞壁，得到部分甲酯化的高半乳糖醛酸(HGA)，与陆地植物中的HGA相同。其他常见于陆地植物的果胶没有被检测到，尽管这些聚合物中的一些选定成分存在。用针对高等植物HGA表位(如JIM5、JIM7、LM7、2F4和PAM1)的特异性单抗标记表明，壁复合体和外层突起由HGA组成，它与钙离子有显著的络合作用。JIM5和JIM7标记表明，高度甲酯化的HGA被分泌到细胞分裂的峡部，也就是活跃的壁分泌部位。随着HGA被转移到更多的极地区域，发生了非嵌段方式的脱酯作用。这反过来又允许钙结合和形成坚硬的外壁层。HGA沉积的图案为果胶参与植物细胞壁发育的复杂过程提供了有趣的见解。
Plant cell walls are essential for proper growth, development, and interaction with the environment. It is generally accepted that land plants arose from aquatic ancestors which are sister groups to the charophycean algae (i.e., Streptophyta), and study of wall evolution during this transition promises insight into structure-function relationships of wall components. In this paper, we explore wall evolutionary history by studying the incorporation of pectin polymers into cell walls of the model organism Penium margaritaceum, a simple single-cell desmid. This organism produces only a primary wall consisting of three fibrillar or fibrous layers, with the outermost stratum terminating in distinct, calcified projections. Extraction of isolated cell walls with trans-1,2-diaminocyclohexane-N,N,N',N'-tetraacetic acid yielded a homogalacturonan (HGA) that was partially methyl esterified and equivalent to that found in land plants. Other pectins common to land plants were not detected, although selected components of some of these polymers were present. Labeling with specific monoclonal antibodies raised against higher-plant HGA epitopes (e.g., JIM5, JIM7, LM7, 2F4, and PAM1) demonstrated that the wall complex and outer layer projections were composed of the HGA which was significantly calcium complexed. JIM5 and JIM7 labeling suggested that highly methyl esterified HGA was secreted into the isthmus zone of dividing cells, the site of active wall secretion. As the HGA was displaced to more polar regions, de-esterification in a non-blockwise fashion occurred. This, in turn, allowed for calcium binding and the formation of the rigid outer wall layer. The patterning of HGA deposition provides interesting insights into the complex process of pectin involvement in the development of the plant cell wall.