《植物生理学报》 2011, 47(9): 872-878

3-羰基辛酰基高丝氨酸内酯诱导拟南芥根细胞Ca²⁺内流

张哲^1,2,3, 张霞^1,2, 边子睿^1,2,3, 宋水山^1,2,*

1河北省科学院生物研究所, 石家庄050051; 2河北省农作物主要病害微生物控制工程技术研究中心, 石家庄050051; 3河北工 业大学化工学院, 天津300130

通信作者：宋水山；E-mail: shuishans@hotmail.com；Tel: 0311-83999012

摘　要：

N-酰基高丝氨酸内酯(AHLs)是革兰氏阴性细菌群体感应系统(QS)中的胞间通讯信号分子。近年的研究表明AHLs可以调控植物生长发育及防卫反应, 但其调控机制尚不清楚。本研究以拟南芥为材料, 采用3-羰基辛酰基高丝氨酸内酯(3OC8-HSL)处理转水母发光蛋白基因的拟南芥幼根细胞, 利用冷光仪检测3OC8-HSL对拟南芥根细胞中胞质游离Ca2+浓度([Ca2+]cyt)变化的影响, 同时采用Ca2+专一性螯合剂EGTA和Ca2+通道抑制剂预处理转基因拟南芥根细胞, 用全细胞膜片钳技术分析3OC8-HSL诱导拟南芥根细胞中[Ca2+]cyt升高的Ca2+来源。结果表明, 3OC8-HSL可诱导拟南芥根细胞中[Ca2+]cyt瞬时升高。这种诱导效应可被EGTA、异搏定(verapamil)、LaCl3所抑制, 但LiCl预处理对这种诱导效应无影响。膜片钳分析结果显示, 3OC8-HSL可激活质膜Ca2+通道, 增加胞外Ca2+内流。说明细菌AHLs可诱导植物Ca2+信号产生, 且这种Ca2+信号主要源于胞外Ca2+内流, 暗示Ca2+信使系统参与植物对细菌QS信号的响应。

关键词： N-酰基高丝氨酸内酯; 细菌群体感应; 钙信使; 拟南芥

收稿：2011-06-22   修定：2011-08-02

资助：国家重点基础研究发展计划(2009CB126010)、河北省自然科学基金(C2006000707)和河北省重点基础研究计划项目(08965506D)。

N-3-oxo-Octanoyl-Homoserine Lactone Induces Intracellular Ca²⁺ Elevation in Arabidopsis Root Cells

ZHANG Zhe^1,2,3, ZHANG Xia^1,2, BIAN Zi-Rui^1,2,3, SONG Shui-Shan^1,2,*

¹Biology Institute, Hebei Academy of Sciences, Shijiazhuang 050051, China; ²Hebei Engineering and Technology Center of Microbiological Control on Main Crop Disease, Shijiazhuang 050051, China; ³School of Chemical Engineering, Hebei University of Technology, Tianjin 300130, China

Corresponding author: SONG Shui-Shan; E-mail: shuishans@hotmail.com; Tel: 0311-83999012

Abstract:

N-acyl-L-homoserine lactones (AHLs) are the signal molecules which mediate the quorum-sensing (QS) in Gram-negative bacteria. In recent years, the accumulating evidence indicates that AHLs are able to regulate the growth, development and defense response of plants. However, the mechanisms by which plant responses to bacterial QS signal molecule is little known. In this study, the change of cytosolic free Ca²⁺ concentration ([Ca²⁺]_cyt) and the activities of calcium channel in Arabidopsis thaliana root cells induced by N-3-oxooctanoyl-homoserine lactone(3OC₈-HSL) were monitored by both microplate luminometer and the whole-cell patch clamping. A transient elevation in [Ca²⁺]_cyt was observed upon the treatment with 3OC₈-HSL in the root cells of Arabidopsis expressing the Ca²⁺ bioluminescent indicator aequorin. The elevation in [Ca²⁺]_cyt induced by 3OC₈-HSL treatment was completely blocked by pretreatment with EGTA, verapamil and LaCl₃, but was unaffected by LiCl pretreatment. Furthermore, a hyperpolarization-activated calcium permeable channel was recorded in plasma membrane of Arabidopsis root tip protoplast. The Ca²⁺ current intensity increased remarkably after 3OC₈-HSL treatment. The results reveal that 3OC₈-HSL can induce the generation of Ca²⁺ signal in Arabidopsis root cells and the cytosolic free Ca²⁺ increase induced by 3OC₈-HSL comes mainly from the extracellular space, illuminating that Ca²⁺ signaling participates in the plant cells sensing to bacterial QS signals.

Key words: N-acyl-homoserine lactones; bacterial quorum-sensing; Ca²⁺ signaling; Arabidopsis thaliana