A model suite of green algae within the Scenedesmaceae for investigating contrasting desiccation tolerance and morphology
A model suite of green algae within the Scenedesmaceae for investigating contrasting desiccation tolerance and morphology
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DOI：
10.1242/jcs.212233
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发表时间：
2018-04-01
影响因子：
4
通讯作者：
Bezanilla, Magdalena
中科院分区：
文献类型：
--
作者：
Cardon, Zoe G.;Peredo, Elena L.;Bezanilla, Magdalena
生活在沙漠微生物外壳中的微型绿藻在系统发育上具有显著的多样性，许多沙漠谱系都是从水生祖先独立进化而来的。在这里，我们研究了五种沙漠和水生植物，研究了单细胞和多细胞后代的干燥耐受性和释放机制。活细胞染色和延时共聚焦成像与透射电子显微镜相结合，证实了沙漠和水生物种都通过多重（而不是二元）分裂，尽管三个物种的后代是单细胞的，两个物种的后代是多细胞的（连接在一个片状的共生菌体中）。在分裂过程中，高尔基复合体定位于细胞核附近，所有物种在细胞质分裂时都表现出子细胞团在母细胞壁内的动态旋转。通过脱水/再水化循环期间的光合效率来评估，五种植物的不同脱水耐受性伴随着细胞内活性氧（ROS）的不同积累，使用对细胞内ROS敏感的染料检测。进一步的比较研究将旨在了解支持单细胞和多细胞共生形态的遗传、超微结构和生理特征，以及scenedesmacae中代表物种在生态多样性甚至极端栖息地定居的能力。
Microscopic green algae inhabiting desert microbiotic crusts are remarkably diverse phylogenetically, and many desert lineages have independently evolved from aquatic ancestors. Here we worked with five desert and aquatic species within the family Scenedesmaceae to examine mechanisms that underlie desiccation tolerance and release of unicellular versus multicellular progeny. Live cell staining and time-lapse confocal imaging coupled with transmission electron microscopy established that the desert and aquatic species all divide by multiple (rather than binary) fission, although progeny were unicellular in three species and multicellular (joined in a sheet-like coenobium) in two. During division, Golgi complexes were localized near nuclei, and all species exhibited dynamic rotation of the daughter cell mass within the mother cell wall at cytokinesis. Differential desiccation tolerance across the five species, assessed from photosynthetic efficiency during desiccation/rehydration cycles, was accompanied by differential accumulation of intracellular reactive oxygen species (ROS) detected using a dye sensitive to intracellular ROS. Further comparative investigation will aim to understand the genetic, ultrastructural and physiological characteristics supporting unicellular versus multicellular coenobial morphology, and the ability of representatives in the Scenedesmaceae to colonize ecologically diverse, even extreme, habitats.