Cytokinesis in land plants involves the formation of a cell plate that develops into the new cell wall. Callose is a β-1,3 glucan that transiently accumulates at later stages of cell plate development and is thought to stabilize the delicate membrane network of the cell plate as it expands. Cytokinetic callose deposition is currently considered specific to multicellular plant species as it has not been detected in unicellular algae. Here we present callose at the cytokinesis junction of the unicellular charophyte, Penium margaritaceum. Notably, callose deposition at the division plane of P. margaritaceum showed distinct, spatiotemporal patterns that could represent distinct roles of this polymer in cytokinesis and cell wall assembly. Pharmacological inhibition of cytokinetic callose deposition by Endosidin 7 treatment resulted in cytokinesis defects, consistent with the essential role for this polymer in P. margaritaceum cell division. Cell wall deposition and assembly at the isthmus zone was also affected by the absence of callose, demonstrating the dynamic nature of new wall assembly in P. margaritaceum. The identification of candidate callose synthase genes provides molecular evidence for callose biosynthesis in P. margaritaceum. The evolutionary implications of cytokinetic callose in this unicellular Zygnematopycean alga is discussed in the context of the conquest of land by plants.

中文翻译：

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ose质沉积对于完成单细胞藻类玛格丽塔酒中的胞质分裂是必不可少的

陆地植物的细胞分裂涉及细胞板的形成，该细胞板发展成新的细胞壁。ose质是一种β-1,3葡聚糖，可在细胞板发育的后期短暂积累，并被认为可在细胞板扩张时稳定其精细的膜网络。目前认为细胞动力学的ose沉积对多细胞植物物种是特定的，因为在单细胞藻类中尚未检测到。在这里，我们在单细胞的藻类，玛格丽塔酒渣霉的胞质分裂连接处呈现call质。值得注意的是，在玛格丽特体育的分裂平面上的call质沉积显示出独特的时空模式，可以代表这种聚合物在胞质分裂和细胞壁组装中的独特作用。药理学抑制Endosidin 7处理的细胞动力学call质沉积导致胞质分裂缺陷，与这种聚合物在玛格丽特杆菌细胞分裂中的基本作用一致。地峡区域的细胞壁沉积和组装也受到不存在call的影响，这证明了玛格丽塔体育中新壁组装的动力学性质。候选call质合酶基因的鉴定为玛格丽特体育中的ose质生物合成提供分子证据。在植物占领土地的背景下，讨论了这种单细胞藻类藻类藻中细胞动力学kin的进化意义。