Colcombet Jean, Mathieu Yves, Peyronnet Remi, Agier Nicolas, Lelièvre Françoise, Barbier-Brygoo Hélène, Frachisse Jean-Marie
Present address: Unité de Recherche en Génomique Végétale, 2 rue Gaston Crémieux, 91057 Evry, France.
Institut des Sciences du Végétal, CNRS UPR 2355, 22 Avenue de la Terrasse, 91198 Gif sur Yvette, France.
Funct Plant Biol. 2009 Sep;36(9):832-843. doi: 10.1071/FP09096.
Plants are constantly exposed to environmental biotic and abiotic stresses. Plants cells perceive these factors and trigger early responses followed by delayed and complex adaptation processes. Using cell suspensions of Arabidopsis thaliana (L.) as a cellular model, we investigated the role of plasma membrane anion channels in Reactive Oxygen Species (ROS) production and in cell death which occurs during non-host pathogen infection. Protoplasts derived from Arabidopsis suspension cells display two anion currents with characteristics very similar to those of the slow nitrate-permeable (S-type) and rapid sulfate-permeable (R-type) channels previously characterised in hypocotyl cells and other cell types. Using seven inhibitors, we showed that the R-type channel and ROS formation in cell cultures present similar pharmacological profiles. The efficiency of anion channel blockers to inhibit ROS production was independent of the nature of the triggering signal (osmotic stress or general elicitors of plant defence), indicating that the R-type channel represents a crossroad in the signalling pathways leading to ROS production. In a second step, we show that treatment with R-type channel blockers accelerates cell death triggered by the non-specific plant pathogen Xanthomonas campestris. Finally, we discuss the hypothesis that the R-type channel is involved in innate immune response allowing cell defence via antibacterial ROS production.
植物不断受到环境生物和非生物胁迫。植物细胞感知这些因素并触发早期反应，随后是延迟且复杂的适应过程。我们以拟南芥的细胞悬浮液作为细胞模型，研究了质膜阴离子通道在活性氧（ROS）产生以及非寄主病原体感染期间发生的细胞死亡中的作用。源自拟南芥悬浮细胞的原生质体表现出两种阴离子电流，其特征与先前在下胚轴细胞和其他细胞类型中表征的缓慢硝酸盐通透（S型）和快速硫酸盐通透（R型）通道非常相似。使用七种抑制剂，我们表明细胞培养物中的R型通道和ROS形成呈现相似的药理学特征。阴离子通道阻滞剂抑制ROS产生的效率与触发信号的性质（渗透胁迫或植物防御的一般激发子）无关，这表明R型通道代表了导致ROS产生的信号通路中的一个交叉点。在第二步中，我们表明用R型通道阻滞剂处理会加速由非特异性植物病原体野油菜黄单胞菌触发的细胞死亡。最后，我们讨论了R型通道参与先天免疫反应，通过产生抗菌ROS实现细胞防御的假说。
