The maize C system of cytoplasmic male sterility (CMS) and its fertility restoration gene Rf4 have been widely used for maize hybrid production; however, the underlying mechanism is still uncertain. The sterility factor functions in mitochondria, where it interacts directly or indirectly with the restorer. Mitoproteomics can capture all participants involved in CMS and restoration at the organelle level. In the present study, we identified and quantified anther mitochondrial proteins from CMS, maintainer and restorer lines. We obtained 14,528 unique peptides belonging to 3,369 proteins. Comparative analysis of 1840 high‐confidence proteins revealed 68 were differentially accumulated proteins likely involved in CMS or its restoration within mitochondria. These proteins were mainly associated with fatty acid metabolism, amino acid metabolism and protein‐processing pathways. These results suggest that an energy deficiency caused by the sterility factor hinders other proteins or protein complexes required for pollen development through nuclear‐mitochondrial interaction. The restorer factor may boost the energy generation by activating alternative metabolic pathways and by improving the post‐translation processing efficiency of proteins in energy‐producing complexes to restore pollen fertility. Our findings may aid detailed molecular analysis and contribute to a better understanding of maize CMS‐C restoration and sterility.

中文翻译：

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玉米CMS‐C无菌，保持和恢复花药中线粒体蛋白质的比较蛋白质组学分析

玉米C型细胞质雄性不育及其育性恢复基因Rf4已广泛用于玉米杂交生产；但是，其潜在机制仍不确定。无菌因子在线粒体中起作用，在那里它直接或间接与修复体相互作用。Mitoproteomics可以捕获所有参与CMS和细胞器水平恢复的参与者。在本研究中，我们从CMS，维持和恢复系中鉴定并定量了花药线粒体蛋白。我们获得了3,369种蛋白质中的14,528种独特的肽。对1840种高可信度蛋白质的比较分析显示，有68种差异累积的蛋白质可能参与了CMS或其在线粒体内的恢复。这些蛋白质主要与脂肪酸代谢，氨基酸代谢和蛋白质加工途径有关。这些结果表明，由不育因子引起的能量缺乏会阻碍通过核线粒体相互作用而产生花粉的其他蛋白质或蛋白质复合物。恢复因子可以通过激活其他代谢途径和提高能量产生复合物中蛋白质的翻译后加工效率来恢复花粉繁殖，从而促进能量的产生。我们的发现可能有助于详细的分子分析，并有助于更好地了解玉米CMS-C的恢复和不育。恢复因子可以通过激活替代代谢途径和提高能量产生复合物中蛋白质的翻译后加工效率来恢复花粉繁殖力，从而促进能量产生。我们的发现可能有助于详细的分子分析，并有助于更好地了解玉米CMS-C的恢复和不育。恢复因子可通过激活替代代谢途径和提高能量产生复合物中蛋白质的翻译后加工效率来恢复花粉繁殖力，从而促进能量产生。我们的发现可能有助于详细的分子分析，并有助于更好地了解玉米CMS-C的恢复和不育。