Peng Leilei, Xiao Haijun, Xu Yanghong, Huang Zhihao, Yang Xuan, Lv Chen, Huang Linghui, Hu Jun
State Key Laboratory of Hybrid Rice, Engineering Research Center for Plant Biotechnology and Germplasm Utilization of Ministry of Education, College of Life Sciences, Wuhan University, Wuhan 430072, China.
Key Laboratory of Bio-Resource and Eco-Environment of Ministry of Education, College of Life Sciences, Sichuan University, Chengdu, 610065, Sichuan, China.
Plant Physiol. 2025 May 7. doi: 10.1093/plphys/kiaf187.
The RNA-binding proteins (RBPs) encoded by the nucleus are essential for RNA metabolism in eukaryotes. Pentatricopeptide repeat (PPR) proteins, a large subset of RBPs, are essential for plant development and reproduction by participating in organellar RNA processing. Here, we identified an E-type PPR protein, PPR767, which functions in mitochondria. Knocking out PPR767 resulted in decreased plant height, thinner stems, shorter and narrower blades, and consequently affected yield traits compared to those of the wild-type. PPR767 primarily participated in the RNA editing of four sites related to NADH dehydrogenase (Nad), including nad1-674, nad3-155, nad3-172, and nad7-317. PPR767 interacted with multiple organellar RNA editing factors (MORFs), including MORF1 and MORF8, suggesting that the editosome in rice (Oryza sativa) is complex. The mutants showed decreased mitochondrial complex Ⅰ activity and compromised mitochondrial structure. Furthermore, mutation of PPR767 influenced rice drought tolerance and the expression levels of genes involved in reactive oxygen species (ROS) accumulation. Therefore, PPR767 is essential for complex Ⅰ activity by properly regulating the RNA editing efficiency of mitochondrial genes and affects drought tolerance by modulating ROS content in rice. Our findings provide valuable insights into the mechanisms by which PPRs fulfil their functions.
细胞核编码的RNA结合蛋白（RBPs）对于真核生物的RNA代谢至关重要。作为RBPs的一个大子集，五肽重复序列（PPR）蛋白通过参与细胞器RNA加工对植物发育和繁殖至关重要。在此，我们鉴定了一种在线粒体中起作用的E型PPR蛋白PPR767。与野生型相比，敲除PPR767导致株高降低、茎变细、叶片更短更窄，从而影响产量性状。PPR767主要参与与NADH脱氢酶（Nad）相关的四个位点的RNA编辑，包括nad1-674、nad3-155、nad3-172和nad7-317。PPR767与多种细胞器RNA编辑因子（MORFs）相互作用，包括MORF1和MORF8，这表明水稻（Oryza sativa）中的编辑体很复杂。突变体显示线粒体复合体Ⅰ活性降低，线粒体结构受损。此外，PPR767的突变影响水稻的耐旱性以及参与活性氧（ROS）积累的基因的表达水平。因此，PPR767通过适当调节线粒体基因的RNA编辑效率对复合体Ⅰ活性至关重要，并通过调节水稻中的ROS含量影响耐旱性。我们的研究结果为PPR发挥其功能的机制提供了有价值的见解。
