CHEN Chang-zhao, WANG Ya-Liang, HE Meng-xing, LI Zhi-wen, SHEN Lan, LI Qing, RE De-yong, HU Jiang, ZHU Li, ZHANG Guang-heng, GAO Zhen-yu, , GUO Long-biao, QIAN Qian, ZHANG Qiang

Journal of Integrative Agriculture; Available online 6 August 2022

https://doi.org/10.1016/j.jia.2022.08.026

Abstract

Photosynthesis occurs mainly in chloroplasts, whose development is regulated by proteins encoded by nuclear genes. Among them, pentapeptide repeat (PPR) proteins participate in organelle RNA editing. Although there are more than 450 members of the PPR protein family in rice, only a few have been shown to affect RNA editing in rice chloroplasts. New rice germplasm and mutants were created by gene editing technology, which could be used for rice breeding and gene function study, respectively. This study evaluated the functions of OsPPR9 in chloroplast RNA editing in rice. The Osppr9 mutants were obtained by CRISPR/Cas9, which showed yellowing leaves and a lethal phenotype, with suppressed expression of genes associated with chloroplast development and accumulation of photosynthetic-related proteins. In addition, loss of OsPPR9 protein function reduces the editing efficiency of rps8-C182, rpoC2-C4106, rps14-C80 and ndhB-C611 RNA editing sites, which affects chloroplast growth and development in rice. Our data showed that OsPPR9 is highly expressed in rice leaves and encodes a DYW-PPR protein that is localized in chloroplasts. Besides, the OsPPR9 protein was shown to interact with OsMORF2 and OsMORF9. Together, our findings provide insights into the role of the PPR protein in regulating chloroplast development in rice.

See https://www.sciencedirect.com/science/article/pii/S2095311922001046

Fig. 1 OsPPR9 encodes a DYW-PPR type protein that is localized in the chloroplasts. A, domain analysis of the OsPPR9 protein. OsPPR9 includes fourteen PPR motifs, an E1/E2 domain and a DYW domain. B, phylogenic analysis of the OsPPR9 gene in various species. C, subcellular localization of OsPPR9 in rice protoplasts. Bar=10 μm.