Department of Plant and Soil Sciences, Delaware Biotechnology Institute, University of Delaware, Newark, Delaware 19711, USA.
Plant Cell. 2013 Jun;25(6):2315-29. doi: 10.1105/tpc.113.110676. Epub 2013 Jun 7.
In plants, mounting an effective innate immune strategy against microbial pathogens involves triggering local cell death within infected cells as well as boosting the immunity of the uninfected neighboring and systemically located cells. Although not much is known about this, it is evident that well-coordinated cell-cell signaling is critical in this process to confine infection to local tissue while allowing for the spread of systemic immune signals throughout the whole plant. In support of this notion, direct cell-to-cell communication was recently found to play a crucial role in plant defense. Here, we provide experimental evidence that salicylic acid (SA) is a critical hormonal signal that regulates cell-to-cell permeability during innate immune responses elicited by virulent bacterial infection in Arabidopsis thaliana. We show that direct exogenous application of SA or bacterial infection suppresses cell-cell coupling and that SA pathway mutants are impaired in this response. The SA- or infection-induced suppression of cell-cell coupling requires an enhanced desease resistance1- and nonexpressor of pathogenesis-related genes1-dependent SA pathway in conjunction with the regulator of plasmodesmal gating Plasmodesmata-located protein5. We discuss a model wherein the SA signaling pathway and plasmodesmata-mediated cell-to-cell communication converge under an intricate regulatory loop.
在植物中，为了对抗微生物病原体，需要启动有效的先天免疫策略，这包括在受感染的细胞内引发局部细胞死亡，同时增强未感染的邻近细胞和系统定位细胞的免疫能力。虽然对此知之甚少，但很明显，在这个过程中，协调良好的细胞间信号传递对于将感染局限在局部组织中，同时允许系统免疫信号在整个植物中传播至关重要。支持这一观点的是，最近发现直接的细胞间通信在植物防御中起着关键作用。在这里，我们提供了实验证据，表明水杨酸（SA）是一种关键的激素信号，可调节拟南芥中由毒力细菌感染引发的先天免疫反应中的细胞间通透性。我们表明，直接外源性应用 SA 或细菌感染可抑制细胞间偶联，并且 SA 途径突变体在此反应中受损。SA 或感染诱导的细胞间偶联抑制需要增强依赖于疾病抗性 1 和不表达与发病相关基因 1 的 SA 途径，以及调节胞间连丝门控的质膜蛋白 5。我们讨论了一个模型，其中 SA 信号通路和胞间连丝介导的细胞间通讯在一个复杂的调控回路中汇聚。
