ECD1 functions as an RNA-editing trans-factor of rps14-149 in plastids and is required for early chloroplast development in seedlings

• Published in: Journal of experimental botany Vol. 69; no. 12; pp. 3037 - 3051
• Main Authors: Jiang, Tian, Zhang, Jing, Rong, Liwei, Feng, Yanjiang, Wang, Qi, Song, Qiulai, Zhang, Lixin, Ouyang, Min
• Format: Journal Article
• Language: English
• Published: UK Oxford University Press 25.05.2018
• Subjects: Research Papers; RNA editing; Arabidopsis; early stages; pentatricopeptide repeat protein (PPR); chloroplast development; cotyledon; Early Chloroplast Development 1 (ECD1)
• ISSN: 0022-0957; 1460-2431
• DOI: 10.1093/jxb/ery139

The pentatricopeptide repeat protein ECD1 functions as an RNA-editing trans-factor in plastids of cotyledons and is necessary for early chloroplast development in Arabidopsis seedlings. Abstract Chloroplast development is a highly complex process and the regulatory mechanisms have not yet been fully characterized. In this study, we identified Early Chloroplast Development 1 (ECD1), a chloroplast-localized pentatricopeptide repeat protein (PPR) belonging to the PLS subfamily. Inactivation of ECD1 in Arabidopsis led to embryo lethality, and abnormal embryogenesis occurred in ecd1/+ heterozygous plants. A decrease in ECD1 expression induced by RNAi resulted in seedlings with albino cotyledons but normal true leaves. The aberrant morphology and under-developed thylakoid membrane system in cotyledons of RNAi seedlings suggests a role of ECD1 specifically in chloroplast development in seedlings. In cotyledons of ECD1-RNAi plants, RNA-editing of rps14-149 (encoding ribosomal protein S14) was seriously impaired. In addition, dramatically decreased plastid-encoded RNA polymerase-dependent gene expression and abnormal chloroplast rRNA processing were also observed. Taken together, our results indicate that ECD1 is indispensable for chloroplast development at the seedling stage in Arabidopsis.