ORIGINAL RESEARCH article

Front. Plant Sci.

Sec. Plant Bioinformatics

Volume 16 - 2025 | doi: 10.3389/fpls.2025.1556332

Super-Large Record-Breaking Mitochondrial Genome of Cathaya argyrophylla in Pinaceae

Provisionally accepted
Kerui HuangKerui Huang1*Wenbo XuWenbo Xu2Haoliang HuHaoliang Hu1Jiang Xiao-LongJiang Xiao-Long3Lei SunLei Sun4Wenyan ZhaoWenyan Zhao1Binbin LongBinbin Long1Shaogang FanShaogang Fan1Zhibo ZhouZhibo Zhou1Ping MoPing Mo1Xiaocheng JiangXiaocheng Jiang5Jianhong TianJianhong Tian4Aihua DengAihua Deng1Peng XiePeng Xie1Yun WangYun Wang1
  • 1Hunan University of Arts and Science, Changde, China
  • 2China Pharmaceutical University, Nanjing, Jiangsu Province, China
  • 3Central South University, Changsha, Hunan Province, China
  • 4Huaihua University, Huaihua, China
  • 5Hunan Normal University, Changsha, Hunan Province, China

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Mitochondrial genomes (Mitogenomes) in Pinaceae are notable for their large size and structural complexity. In this study, we analyzed the mitogenome of Cathaya argyrophylla, a critically endangered and endemic "plant panda" in China, uncovering a record-breaking size of 18.99 Mb. To understand the drivers of this exceptional genome expansion, we performed comparative analyses with other Pinaceae species of varying mitogenome sizes and other gymnosperms. We examined repeat sequences, long interspersed nuclear elements, long terminal repeats, RNA editing events, chloroplast-derived sequence transfers (mtpts), and nuclear genome homology. Our results indicate that while C. argyrophylla and other extremely large Pinaceae mitogenomes possess substantial repeat sequences and elevated transposon activity, these factors alone do not explain the genome size. Significant incorporation of chloroplast-derived sequences was observed, underscoring the importance of plastid-to-mitochondrial DNA transfer. Additionally, large mitogenomes exhibited distinct RNA editing patterns and reduced nuclear homology compared to smaller genomes. These findings reveal that massive mitogenomes in Pinaceae are characterized by a combination of features, including substantial repeat content, elevated transposon activity, and extensive plastid sequence integration, alongside distinct RNA editing and nuclear homology patterns. This comprehensive mitogenome analysis not only enhances our understanding of plant mitogenome evolution but also lays a genomic foundation for the conservation and potential industrial applications of this valuable relict species.

Keywords: Cathaya argyrophylla, Super-large mitochondrial genome, Pinaceae, RNA-editing, MTPTs

Received: 06 Jan 2025; Accepted: 28 May 2025.

Copyright: © 2025 Huang, Xu, Hu, Xiao-Long, Sun, Zhao, Long, Fan, Zhou, Mo, Jiang, Tian, Deng, Xie and Wang. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.

* Correspondence: Kerui Huang, Hunan University of Arts and Science, Changde, China

Disclaimer: All claims expressed in this article are solely those of the authors and do not necessarily represent those of their affiliated organizations, or those of the publisher, the editors and the reviewers. Any product that may be evaluated in this article or claim that may be made by its manufacturer is not guaranteed or endorsed by the publisher.

Supplementary Material