Actin-dependence of the chloroplast cold positioning response in the liverwort Marchantia polymorpha L.
Actin-dependence of the chloroplast cold positioning response in the liverwort Marchantia polymorpha L.
复制标题
Liverwort Marthantia多形形状的叶绿体冷定位反应的肌动蛋白依赖性。
作者：
Kimura S;Kodama Y
叶绿体的亚细胞定位可以随着环境的变化而改变，如光和温度。例如，在叶肉细胞中，叶绿体在强光下沿背斜细胞壁定位，在弱光下沿周周细胞壁定位。这些类型的定位响应与光合优化有关。在光介导的叶绿体定位反应中，叶绿体以肌动蛋白依赖的方式移动到适当的位置，尽管也有一些例外依赖于微管。即使在低强度光照下，在低温（例如5°C）下，叶绿体也沿背斜细胞壁定位；这种现象被称为叶绿体冷定位。在这项研究中，我们分析了在多形地茅中叶绿体冷定位是否依赖于肌动蛋白丝和/或微管。当用药物处理肝茅细胞使肌动蛋白丝解聚时，叶绿体冷定位完全被抑制。相反，叶绿体冷定位不受微管解聚药物处理的影响。这些结果表明多形草叶绿体冷定位依赖于动作蛋白。利用基于荧光蛋白的荧光探针对活苔细胞中叶绿体冷定位响应过程中的肌动蛋白丝进行了可视化观察，从而记录了其在叶绿体冷定位响应过程中的行为。
The subcellular positioning of chloroplasts can be changed by alterations in the environment such as light and temperature. For example, in leaf mesophyll cells, chloroplasts localize along anticlinal cell walls under high-intensity light, and along periclinal cell walls under low-intensity light. These types of positioning responses are involved in photosynthetic optimization. In light-mediated chloroplast positioning responses, chloroplasts move to the appropriate positions in an actin-dependent manner, although some exceptions also depend on microtubule. Even under low-intensity light, at low temperature (e.g., 5°C), chloroplasts localize along anticlinal cell walls; this phenomenon is termed chloroplast cold positioning. In this study, we analyzed whether chloroplast cold positioning is dependent on actin filaments and/or microtubules in the liverwort Marchantia polymorpha L. When liverwort cells were treated with drugs for the de-polymerization of actin filaments, chloroplast cold positioning was completely inhibited. In contrast, chloroplast cold positioning was not affected by treatment with a drug for the de-polymerization of microtubules. These observations indicate the actin-dependence of chloroplast cold positioning in M. polymorpha. Actin filaments during the chloroplast cold positioning response were visualized by using fluorescent probes based on fluorescent proteins in living liverwort cells, and thus, their behavior during the chloroplast cold positioning response was documented.