Chloroplasts are important for plant growth and development. RNA editing in chloroplast converts cytidines (Cs) to uridines (Us) at specific transcript positions and provides a correction mechanism to restore conserved codons or creates start or stop codons. However, the underlined molecular mechanism is not yet fully understood. In the present study, we identified a thermo-sensitive mutant in leaf color 1 (tsl1) and found that TSL1 is allelic to DELAYED GREENING 1 (DG1). The missense mutation of DG1 in tsl1 mutant confers a high temperature sensitivity and impaired chloroplast development at an elevated ambient temperature in Arabidopsis. Subsequent analysis showed that chloroplast RNA editing at several sites including accD-1568, ndhD-2, and petL-5 is impaired in tsl1 mutant plants grown at an elevated temperature. DG1 interacts with MORF2 and other proteins such as DYW1 and DYW2 involved in chloroplast RNA editing. In vitro RNA electrophoretic mobility shift assay demonstrated that DG1 binds to RNA targets such as accD, ndhD, and petL. Thus, our results revealed that DG1 is important for maintaining chloroplast mRNA editing in Arabidopsis.

叶绿体对植物的生长和发育很重要。叶绿体中的RNA编辑可将特定转录物位置的胞苷（Cs）转换为尿苷（Us），并提供一种纠正机制来还原保守密码子或创建起始或终止密码子。但是，下划线的分子机理尚未完全理解。在本研究中，我们确定了叶色1（tsl1）的热敏突变体，并发现TSL1与DELAYED GREENING 1（DG1）等位基因。在DG1的错义突变TSL1突变体赋予高的温度敏感性和受损的叶绿体发育在升高的环境温度下的拟南芥。随后的分析表明，在高温下生长的tsl1突变植物中，叶绿体RNA在accD -1568，ndhD -2和petL -5等多个位点的编辑受到损害。DG1与MORF2和其他参与叶绿体RNA编辑的蛋白质（例如DYW1和DYW2）相互作用。体外RNA电泳迁移率变动分析表明DG1与RNA靶标（例如accD，ndhD和petL）结合。因此，我们的结果表明，DG1对于维持拟南芥中叶绿体mRNA的编辑很重要。