The School of Life Sciences, University of Warwick Coventry, UK.
Front Plant Sci. 2012 Aug 22;3:200. doi: 10.3389/fpls.2012.00200. eCollection 2012.
The endoplasmic reticulum (ER) is a highly dynamic organelle in eukaryotic cells and a major production site of proteins destined for vacuoles, the plasma membrane, or apoplast in plants. At the ER, these secreted proteins undergo multiple processing steps, which are supervised and conducted by the ER quality control system. Notably, processing of secreted proteins can considerably elevate under stress conditions and exceed ER folding capacities. The resulting accumulation of unfolded proteins is defined as ER stress. The efficiency of cells to re-establish proper ER function is crucial for stress adaptation. Besides delivering proteins directly antagonizing and resolving stress conditions, the ER monitors synthesis of immune receptors. This indicates the significance of the ER for the establishment and function of the plant immune system. Recent studies point out the fragility of the entire system and highlight the ER as initiator of programed cell death (PCD) in plants as was reported for vertebrates. This review summarizes current knowledge on the impact of the ER on immune and PCD signaling. Understanding the integration of stress signals by the ER bears a considerable potential to optimize development and to enhance stress resistance of plants.
内质网（ER）是真核细胞中一种高度动态的细胞器，是蛋白质的主要生产场所，这些蛋白质将被运往液泡、质膜或植物的质外体。在内质网中，这些分泌蛋白会经历多个加工步骤，这些步骤由内质网质量控制系统监督和进行。值得注意的是，在应激条件下，分泌蛋白的加工过程会显著增加，并超过内质网的折叠能力。由此产生的未折叠蛋白的积累被定义为内质网应激。细胞重新建立适当内质网功能的效率对于应激适应至关重要。内质网除了直接输送对抗和解决应激条件的蛋白质外，还监测免疫受体的合成。这表明内质网对于植物免疫系统的建立和功能具有重要意义。最近的研究指出了整个系统的脆弱性，并强调了内质网作为植物程序性细胞死亡（PCD）的启动者的作用，这与脊椎动物的报道一致。本综述总结了内质网对免疫和 PCD 信号的影响的最新知识。了解内质网对应激信号的整合具有很大的潜力，可以优化植物的发育并增强其对胁迫的抵抗力。
