To endure environmental stresses, plants have evolved complex regulatory mechanisms involving phytohormones, including abscisic acid (ABA). The function of the plant-specific AT-rich sequence zinc-binding protein (PLATZ) family has not yet been extensively characterized in Arabidopsis (Arabidopsis thaliana). In this report, we evaluated the function of a putative member of the PLATZ family in Arabidopsis, ABA-INDUCED expression 1 (AIN1). We determined that AIN1 expression was induced by ABA and abiotic stresses. AIN1 overexpression (OE) enhanced ABA sensitivity and inhibited primary root elongation, but reduced expression of AIN1 in RNA interference (RNAi) plants produced roots less sensitive to ABA. When treated with ABA, we observed a reduction of meristem size and over-accumulation of reactive oxygen species (ROS) at the root tips of OE lines, demonstrating the importance of AIN1 in plant responses to ABA. A set of ROS scavenger genes showed reduced expression in the OE lines but improved in the RNAi plants relative to Col-0. In addition, we report that exogenous application of reduced glutathione (GSH) rescued the root growth defects seen in AIN1 overexpression lines treated with ABA. In summary, our results suggest that Arabidopsis AIN1 is involved in ABA-mediated inhibition of root elongation by modulating ROS homeostasis.

为了忍受环境压力，植物已经进化出涉及植物激素（包括脱落酸（ABA））的复杂调控机制。植物特异性富AT序列锌结合蛋白（PLATZ）家族的功能尚未在拟南芥（Arabidopsis thaliana）中得到广泛表征。在本报告中，我们评估了拟南芥PLATZ家族推定成员ABA诱导表达1（AIN1）的功能。我们确定AIN1表达是由ABA和非生物胁迫诱导的。AIN1过表达（OE）增强ABA敏感性并抑制初级根伸长，但降低AIN1表达RNA干扰（RNAi）植物中产生的根对ABA的敏感性较低。用ABA处理后，我们观察到OE系根尖的分生组织大小减少和活性氧（ROS）过度积累，证明了AIN1在植物对ABA的响应中的重要性。相对于Col-0，一组ROS清除剂基因在OE系中表达降低，但在RNAi植物中表达提高。此外，我们报告说，还原型谷胱甘肽（GSH）的外源应用挽救了用ABA处理的AIN1过表达品系中看到的根部生长缺陷。总之，我们的结果表明拟南芥AIN1通过调节ROS稳态参与ABA介导的根伸长抑制。