J Integr Plant Biol. ›› 2023, Vol. 65 ›› Issue (3): 755-771.DOI: 10.1111/jipb.13402

• Cell and Developmental Biology • Previous Articles     Next Articles

Rice FLOURY ENDOSPERM22, encoding a pentatricopeptide repeat protein, is involved in both mitochondrial RNA splicing and editing and is crucial for endosperm development

Hang Yang1†, Yunlong Wang1†, Yunlu Tian1†, Xuan Teng1, Zehui Lv1, Jie Lei1, Erchao Duan1, Hui Dong1, Xue Yang1, Yuanyan Zhang1, Yinglun Sun1, Xiaoli Chen1, Xiuhao Bao1, Rongbo Chen1, Chuanwei Gu1, Yipeng Zhang1, Xiaokang Jiang1, Wenyu Ma1, Pengcheng Zhang1, Yi Ji1, Yu Zhang1, Yihua Wang1* and Jianmin Wan1,2*   

  1. 1. State Key Laboratory for Crop Genetics and Germplasm Enhancement, Jiangsu Plant Gene Engineering Research Center, Nanjing Agricultural University, Nanjing 210095, China;
    2. National Key Facility for Crop Resources and Genetic Improvement, Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, Beijing 100081, China
    These authors contributed equally to this work.
    *Correspondences: Jianmin Wan (wanjm@njau.edu.cn, Dr. Wan is fully responsible for the distributions of all materials associated with this article); Yihua Wang (yihuawang@njau.edu.cn)
  • Received:2022-07-26 Accepted:2022-11-04 Online:2022-11-04 Published:2023-03-01

Abstract: Most of the reported P-type pentatricopeptide repeat (PPR) proteins play roles in organelle RNA stabilization and splicing. However, P-type PPRs involved in both RNA splicing and editing have rarely been reported, and their underlying mechanism remains largely unknown. Here, we report a rice floury endosperm22 (flo22) mutant with delayed amyloplast development in endosperm cells. Map-based cloning and complementation tests demonstrated that FLO22 encodes a mitochondrion-localized P-type PPR protein. Mutation of FLO22 resulting in defective trans-splicing of mitochondrial nad1 intron 1 and perhaps causing instability of mature transcripts affected assembly and activity of complex Ⅰ, and mitochondrial morphology and function. RNA-seq analysis showed that expression levels of many genes involved in starch and sucrose metabolism were significantly down-regulated in the flo22 mutant compared with the wild type, whereas genes related to oxidative phosphorylation and the tricarboxylic acid cycle were significantly up-regulated. In addition to involvement in splicing as a P-type PPR protein, we found that FLO22 interacted with DYW3, a DYW-type PPR protein, and they may function synergistically in mitochondrial RNA editing. The present work indicated that FLO22 plays an important role in endosperm development and plant growth by participating in nad1 maturation and multi-site editing of mitochondrial messager RNA.

Key words: endosperm development, Oryza sativa, PPR proteins, RNA editing, RNA splicing

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