Molecular genetic analysis of programmed cell death

程序性细胞死亡（PCD）是一种生理过程，是所有生物生命的一部分。在植物和动物中，PCD对于正常发育和清除受损或感染的细胞至关重要。不同类型的PCD已被描述在植物细胞中响应于发育线索、病原体感染或非生物胁迫。PCD的一个例子可能发生在病原体进入部位的受感染叶片上（所谓的“过敏反应”），以限制病原体传播。这种反应通常与植物中特定抗病机制的诱导有关。 在这项研究计划中，参与细胞死亡和细胞存活途径的激活和调节的早期事件和蛋白质将在植物模型拟南芥中进行表征。一个独特的遗传方法将被用来确定关键的调节器在控制由UV-C辐射诱导的PCD。这些信息将有助于了解细胞存活在某些类型的植物防御反应中是如何受到青睐的，然后可以应用于开发抗虫植物。 第二种方法研究PCD诱导活性的植物毒素，thaxtomin A（TA），这是必不可少的发展的共同疮痂病的马铃薯。我们已经表明，TA激活PCD通过抑制拟南芥细胞悬浮液中的纤维素生物合成。我们将研究TA在整个植物中的作用，并描述激活细胞死亡过程的早期信号。此外，我们已经产生了植物细胞悬浮液，可以在致死浓度的TA存在下生长。将分析这些细胞中基因表达的变化，以确定这些细胞如何存活至TA。我们认为，这些数据将导致植物的发展，更耐受应力扰动植物细胞壁，如TA，创伤和病原体感染。

Programmed cell death (PCD) is a physiological process that is part of the life of all organisms. In plants and animals, PCD is essential for normal development and for the removal of damaged or infected cells. Different types of PCD have been described in plant cells in response to developmental cues, pathogen infection or abiotic stresses. One example of PCD may occur on infected leaves at the site of pathogen entry (the so-called "hypersensitive response") to limit pathogen spread. This response is generally associated with the induction of a specific disease resistance mechanism in the plants.         In this research program, the early events and proteins involved in the activation and regulation of cell death and cell survival pathways will be characterized in the plant model Arabidopsis thaliana. A unique genetic approach will be used to identify key regulators in the control of PCD induced by UV-C irradiation. This information will be useful to understand how cell survival may be favoured in some types of plant defence reactions and could then be applied to the development of symptom-less resistant plants.     A second approach studies the PCD-inducing activity of a phytotoxin, thaxtomin A (TA), that is essential for the development of common scab disease of potato. We have shown that TA activates PCD through inhibition of cellulose biosynthesis in Arabidopsis cell suspensions. We will examine the effect of TA in whole plants and characterize the early signals that activate this process of cell death. Moreover, we have produced plant cell suspensions that can grow in the presence of lethal concentrations of TA. Changes in gene expression in these cells will be analysed to determine how these cells can survive to TA. We think this data will lead to the development of plants that are more tolerant to stresses perturbing the plant cell wall, such as TA, wounding and pathogen infection.