CDE4 encodes a pentatricopeptide repeat protein involved in chloroplast RNA splicing and affects chloroplast development under low-temperature conditions in rice

• 作者: Xinyong Liu Xichun Zhang Ruijie Cao Guiai Jiao Shikai Hu Gaoneng Shao Zhonghua Sheng Lihong Xie Shaoqing Tang Xiangjin Wei Peisong Hu
• 来源期刊: 植物学报（英文版）
• 年，卷（期）: 2021,（10）
• 所属期刊栏目: Molecular Physiology
• 页码范围: 1724-1739
• 页数: 16页
• 语种: 英文

摘要

Pentatricopeptide repeat (PPR) proteins play im-portant roles in the post-transcriptional modification of organellar RNAs in plants. However, the function of most PPR proteins remains unknown. Here, we characterized the rice (Oryza sativa L.) chlorophyll deficient 4 (cde4) mutant which exhibits an albino phenotype during early leaf development, with decreased chlorophyll contents and abnormal chloroplasts at low-temperature (20℃). Positional cloning revealed that CDE4 encodes a P-type PPR protein localized in chloroplasts. In the cde4 mutant, plastid-encoded polymerase (PEP)-dependent transcript levels were significantly reduced, but transcript levels of nuclear-encoded genes were in-creased compared to wild-type plants at 20℃. CDE4 directly binds to the transcripts of the chlor-oplast genes rpl2, ndhA, and ndhB. Intron splicing of these transcripts was defective in the cde4 mutant at 20℃, but was normal at 32℃. Moreover, CDE4 interacts with the guanylate kinase VIRESCENT 2 (V2); overexpression of V2 enhanced CDE4 protein stability, thereby rescuing the cde4 phenotype at 20℃. Our results suggest that CDE4 participates in plastid RNA splicing and plays an important role in rice chloroplast development under low-temperature conditions.