Endomembrane architecture and dynamics during secretion of the extracellular matrix of the unicellular charophyte, Penium margaritaceum
Endomembrane architecture and dynamics during secretion of the extracellular matrix of the unicellular charophyte, Penium margaritaceum
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DOI：
10.1093/jxb/eraa039
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发表时间：
2020-06-11
影响因子：
6.9
通讯作者：
Rose，Jocelyn K. C.
中科院分区：
文献类型：
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作者：
Domozych，David S.;Sun，Li;Rose，Jocelyn K. C.
许多轮藻植物的细胞外基质（ECM）是陆地植物的姊妹类群绿藻的集合体，其结构复杂、大量产生并具有多种基本功能。合成和分泌 ECM 可能需要广泛的分泌装置和内膜系统，但该系统的结构细节尚未完全表征。Penium margaritaceum 是一种用于研究分泌动力学的有价值的单细胞模型轮藻。我们报告说，Penium 具有高度组织的内膜系统，由 150-200 个非移动高尔基体组成，它们将 ECM 成分处理和包装到不同的囊泡组中，这些囊泡运输到皮质细胞质，在那里它们通过细胞质流在细胞周围运输。在固定或瞬时区域，特定的细胞质囊泡与质膜融合并分泌其成分。据观察，细胞外多糖（EPS）的产生发生在高尔基体的一个位置，有时发生在独特的高尔基体杂种中。用布雷菲德菌素 A 处理细胞会破坏高尔基体，并抑制 EPS 分泌和细胞壁扩张。 Penium的内膜系统结构为现存轮藻类如何产生大量ECM提供了机制上的见解，而这些ECM在它们的祖先中促进了陆地殖民化。
The extracellular matrix (ECM) of many charophytes, the assemblage of green algae that are the sister group to land plants, is complex, produced in large amounts, and has multiple essential functions. An extensive secretory apparatus and endomembrane system are presumably needed to synthesize and secrete the ECM, but structural details of such a system have not been fully characterized.Penium margaritaceumis a valuable unicellular model charophyte for studying secretion dynamics. We report thatPeniumhas a highly organized endomembrane system, consisting of 150–200 non-mobile Golgi bodies that process and package ECM components into different sets of vesicles that traffic to the cortical cytoplasm, where they are transported around the cell by cytoplasmic streaming. At either fixed or transient areas, specific cytoplasmic vesicles fuse with the plasma membrane and secrete their constituents. Extracellular polysaccharide (EPS) production was observed to occur in one location of the Golgi body and sometimes in unique Golgi hybrids. Treatment of cells with brefeldin A caused disruption of the Golgi body, and inhibition of EPS secretion and cell wall expansion. The structure of the endomembrane system inPeniumprovides mechanistic insights into how extant charophytes generate large quantities of ECM, which in their ancestors facilitated the colonization of land.