Cell-type-specific calcium responses to drought, salt and cold in the Arabidopsis root
Cell-type-specific calcium responses to drought, salt and cold in the Arabidopsis root
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DOI：
10.1046/j.1365-313x.2000.00786.x
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发表时间：
2000-07-01
期刊：
影响因子：
7.2
通讯作者：
Knight, MR
中科院分区：
文献类型：
--
作者：
Kiegle, E;Moore, CA;Knight, MR
人们对根对非生物胁迫的反应所涉及的信号传递过程知之甚少。拟南芥的根是一个结构简单的根解剖模型系统，可以进行遗传操作。虽然已知根对寒冷、干旱和盐胁迫的反应是细胞质游离钙的增加，但目前还没有关于组成根的不同功能类型的细胞类型的作用的信息(S)。利用在特定细胞类型中表达增强子捕获GAL4的转基因拟南芥来靶向钙报告蛋白aequorin，并将其融合到修饰的黄色荧光蛋白(YFP)中。靶向Aequorin的发光输出使得能够在体内测量特定细胞类型在急性寒冷、渗透和盐胁迫期间细胞内游离钙浓度([Ca2+](Cyt))的变化。作为对急性冷胁迫的响应，所有受试细胞类型以及组成表达aequorin的植物都显示出快速的[Ca~(2+)](Cyt)峰。然而，不同类型的细胞在对冷应激、渗透胁迫(440 mM甘露醇)和盐胁迫(220 MM NaC L)的反应方面存在显著的数量差异，这意味着某些类型的细胞在检测和/或对这些刺激的反应中具有特定的作用。在对渗透胁迫和盐胁迫的反应中，内胚层和中柱细胞表现出与其他类型细胞不同的胞浆钙振荡。Aequorin的靶向表达避免了荧光染料注射所涉及的技术困难以及成分表达的Aequorin缺乏细胞特异性，并揭示了根钙信号转导的新水平的复杂性。
Little is known about the signalling processes involved in the response of roots to abiotic stresses. The Arabidopsis root is a model system of root anatomy with a simple architecture and is amenable to genetic manipulation. Although it is known that the root responds to cold, drought and salt stress with increases in cytoplasmic free calcium, there is currently no information about the role(s) of the functionally diverse cell types that comprise the root. Transgenic Arabidopsis with enhancer-trapped GAL4 expression in specific cell types was used to target the calcium reporting protein, aequorin, fused to a modified yellow fluorescent protein (YFP). The luminescence output of targeted aequorin enabled in vivo measurement of changes in cytosolic free calcium concentrations ([Ca2+](cyt)) in specific cell types during acute cold, osmotic and salt stresses. In response to an acute cold stress, all cell types tested as well as plants constitutively expressing aequorin displayed rapid [Ca2+](cyt) peaks. However, there were significant quantitative differences between different cell types in terms of their response to cold stress, osmotic stress (440 mM mannitol) and salt stress (220 mM NaCl), implying specific roles for certain cell types in the detection and/or response to these stimuli. In response to osmotic and salt stress, the endodermis and pericycle displayed prolonged oscillations in cytosolic calcium that were distinct from the responses of the other cell types tested. Targeted expression of aequorin circumvented the technical difficulties involved in fluorescent dye injection as well as the lack of cell specificity of constitutively expressed aequorin, and revealed a new level of complexity in root calcium signalling.